Prospective Evaluation Methods: The Prospective Evaluation Synthesis

Published by the Government Accountability Office on 1990-11-01.

Below is a raw (and likely hideous) rendition of the original report. (PDF)

                   United States General Accounting Office

GAO                Program Evaluation and Methodology

November 1990
                   Evaluation Methods
                   The Prospective
                   Evaluation Synthesis


          GAO assists congressional decisionmakers in their
          deliberative process by furnishing analytical
          information on issues and options under
          consideration. Many diverse methodologies are
          needed to develop sound and timely answers to the
          questions that are posed by the Congress. To provide
          GAO evaluators with basic information about the
          more commonly used methodologies, GAO’s policy
          guidance includes documents such as methodology
          transfer papers and technical guidelines.

          This methodology transfer paper on prospective
          evaluation synthesis focuses on a systematic method
          for providing the best possible information on, among
          other things, the likely outcomes of proposed
          programs, proposed legislation, the adequacy of
          proposed regulations, or top-priority problems. The
          paper uses a combination of techniques that best
          answer prospective questions involving the analyses
          of alternative proposals and projections of various
          kinds. As GAO receives more requests for
          assessments about the implications of future
          occurrences, evaluators should find this systematic
          approach a beneficial tool to facilitate them in their

          The present transfer paper is one of a series of papers
          issued by the Program Evaluation and Methodology
          Division (PEMD). The purpose of the series is to
          provide GAO evaluators with guides to various
          aspects of audit and evaluation methodology, to
          illustrate applications, and to indicate where more
          detailed information is available. This paper was
          originally authored by Lois-ellin Datta. This reissued
          version supersedes the July 1989 edition.

          Page 1          GAO/PEMD-10.1.10 Prospective Evaluation

We look forward to receiving comments from the
readers of this paper. They should be addressed to
Eleanor Chelimsky at 202-275-1854.

Werner Grosshans
Assistant Comptroller General
Office of Policy

Eleanor Chelimsky
Assistant Comptroller General
for Program Evaluation and

Page 2          GAO/PEMD-10.1.10 Prospective Evaluation
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Preface                                                                  1

Chapter 1                                                                8
What Is a
Chapter 2                                                               17
The Need for
Methods for
Chapter 3                                                               20
                    When the PES Is and Is Not Appropriate              23
Prospective         The PES and the Recommendations GAO                 26
Methods and the       Makes
Synthesis Broadly
Chapter 4                                                               29
                    Defining the Problem                                30
The PES: Initial    Selecting Alternatives to Evaluate                  34
Chapter 5                                                               41
                    The Conceptual Analysis                             41
The PES: Middle     The Operational Analysis                            48
and Final Steps     Testing the Model                                   54

                    Page 4          GAO/PEMD-10.1.10 Prospective Evaluation

                  Presenting the Results                              70

Chapter 6                                                             78
                  Targeted PES                                        78
Variants of the   Variants Using Other Sources of Information         85
Appendixes        Appendix I: A Brief History of the PES and          90
                    Some Other Prospective Methods
                  Appendix II: Data Quality Judgment Models           94
                  Appendix III: A Project Evaluation Profile         104
                  References                                         109
                  Papers in This Series                              115

Tables            Table 1.1: Types of Forward-Looking                 11
                    Questions and What We Are Asked to Do
                  Table 1.2: Features of Retrospective and            16
                    Prospective Methods
                  Table 3.1: Some Prospective Methods                 22
                  Table 3.2: Illustrations of Where a PES Might       27
                    Strengthen Our Recommendations
                  Table 3.3: Situations in Which a PES Should         28
                    and Should Not Be Considered
                  Table 4.1: Steps in the Basic PES Approach          29
                    and Persons Involved
                  Table 4.2: Step 1: Defining the Problem             32
                  Table 4.3: Step 2: Selecting Alternatives to        36
                  Table 5.1: Step 3: Conceptual Analysis              42
                  Table 5.2: Step 4: Operational Analysis             50
                  Table 5.3: Step 5: Testing Key Assumptions          56
                    Against Existing Evidence
                  Table 5.4: Step 6: Presenting Results               71
                  Table 6.1: Targeted PES and Related Critical        78
                  Table II.1: Advantages and Disadvantages of         95
                    Four Data Quality Judgment Models
                  Table II.2: Example of a Fatal Flaws Analysis      100

                  Page 5          GAO/PEMD-10.1.10 Prospective Evaluation

Figures   Figure 3.1: The Triad of Analysis                   23
          Figure 5.1: Underlying Conceptual Model of          45
             the First Bill
          Figure 5.2: Underlying Conceptual Model of          46
             Program A in the Second Bill
          Figure 5.3: Underlying Conceptual Model of          47
             Program B in the Second Bill
          Figure 5.4: Underlying Operational Model of         53
             Program B in the Second Bill
          Table 5.5: Example of Presenting PES                74


          GAO      U.S. General Accounting Office
          PES      Prospective evaluation synthesis

          Page 6          GAO/PEMD-10.1.10 Prospective Evaluation
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Chapter 1

What Is a Prospective Question?

             Why should a GAO evaluator read a paper on the
             prospective evaluation synthesis (PES)? GAO
             evaluators must know about methods such as the PES
             because the changing nature of our work requires us
             to be familiar with the strengths and limitations, and
             the applicability, of ways to answer questions dealing
             with the future. The PES is one these methods.

             GAO is increasingly being asked to answer questions
             about the future that involve analyses of alternative
             proposals and projections of various kinds. To
             support GAO’s capacity to answer these questions
             well, our policy and project manuals have been
             expanded to discuss, for example, different types of
             forecasting and formal modeling approaches and our
             standards for carrying these out. This is because
             systematic methods for dealing with questions about
             the future can be more efficient and yield sounder,
             better-documented answers than more informal
             methods do.

             Many methods exist to deal with forward-looking,
             future-oriented questions. Collectively, they are
             referred to as prospective methods to distinguish
             them from approaches designed to answer questions
             about what is happening now or what has happened
             in the past—that is, retrospective methods.

             Among the prospective methods, we have chosen to
             focus here on the prospective evaluation synthesis.
             GAO developed the PES as a systematic method for
             meeting congressional requests for analyzing
             proposed legislation and helping identify top-priority
             problems. Other applications of the PES might be in
             the analysis of recommendations in draft GAO reports
             and in assessing the adequacy of proposed

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Chapter 1
What Is a Prospective Question?

This paper shows how the tools of evaluation
methodology can be applied in order to provide the
best possible information prospectively on the likely
outcomes of proposed programs. A PES may be
conducted through the comparison of policy or
program alternatives, although it is also useful when
focused on a single policy or program. It is easiest to
perform when an adequate data base already exists.
Fortunately, data bases concerning proposed
programs frequently do exist, primarily because
problems are rarely new. Often they have been
addressed by past programs whose experiences can
be drawn upon for the PES.

In essence, a PES is a combination of the following
activities: (1) a careful, skilled textual analysis of a
proposed program, designed to clarify the implied
goals of that program and what is assumed to get
results, (2) a review and synthesis of evaluation
studies from similar programs, and (3) summary
judgments of likely success, given a future context
that is not too different from the past. In this respect,
the PES resembles the evaluation synthesis approach,
except that the focus of the PES is on how evaluation
studies cast light on the potential for success of the
proposed programs, as opposed to reaching
conclusions about the actual performance of existing

Three other points emerge from the experience with
PES. First, the PES may call for a greater selectivity
than the evaluation synthesis. The latter involves a
comprehensive review of all existing studies, which
can allow us to generalize quite broadly. The
time-driven nature of PES may restrict it to a
narrower focus and the use of strategies, such as
sampling, to balance resources and the need for
external validity. Second, legislators and
congressional staff who have received a PES view it

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Chapter 1
What Is a Prospective Question?

as a useful tool. From the congressional perspective,
a PES means that expert design assistance is available
for a new program at the point when it is most needed
and when it can help convince others of the basic
logic and likely success of the program. Third, from a
public policy perspective, providing understanding
ahead of time about how a program is likely to work
renders an important service by validating the basic
soundness of what is to be undertaken and thereby
increasing its chances for success.

To understand prospective questions, it can be helpful
to begin with some examples of GAO reports. GAO
reported that the passage of a proposed bill, S. 581,
would probably open some jobs to women that were
currently closed and that might otherwise remain
closed after the review required by the secretary of
the Department of Defense was finished. (U.S.
General Accounting Office, 1988h) GAO also informed
the Congress about difficulties with specific Food and
Drug Administration forecasts. These forecasts
predicted the increase in the number of
medical-device problems that would be reported by
hospitals and the number of agency staff that would
be necessary to analyze the reports of those problems
under the proposed Medical Devices Improvement
Act of 1988. We concluded that these forecasts were
biased and not representative of what would be
generated from data obtained from U.S. hospitals in
general. (U.S. General Accounting Office, 1988g) And
GAO found in yet another study that the Internal
Revenue Service needed to review its entire
revenue-estimating process in order to validate the
assumptions used to better reflect actual historical
trends. (U.S. General Accounting Office, 1988k)

These reports illustrate the prospective, or
forward-looking, questions that GAO is often asked to

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                        Chapter 1
                        What Is a Prospective Question?

                        deal with.1 As table 1.1 shows, at least four kinds of
                        forward-looking questions can be identified in reports
                        we have issued already, requests that have been met
                        in ways other than through reports, and our own
                        policies regarding our recommendations.

Table 1.1: Types of
Forward-Looking                                          What we are asked to do
Questions and What We                                Critique
Are Asked to Do                                      others’              Do analyses
                        Question type                analyses             ourselves
                        Anticipate the future        1. How well has      3. What are
                                                     the                  future needs,
                                                     administration       costs, and
                                                     projected            consequences?
                                                     future needs,
                                                     costs, and
                        Improve the future           2. What is the       4. What course
                                                     potential            of action has
                                                     success of an        the best
                                                     administration       potential for
                                                     or                   success and is
                                                     congressional        the most
                                                     proposal?            appropriate for
                                                                          GAO to

                         GAO does not normally make forecasts, although we have done so
                        on special request (for example, in response to our assigned duties
                        under requests related to Gramm-Rudman-Hollings). We do often
                        evaluate the forecasting process and the methodology used. Our
                        past work has indicated, for example, that agencies can improve
                        forecast accuracy by using better techniques and validating
                        predictions. The same points apply to modeling. It should also be
                        noted that other agencies are frequently called upon for
                        forward-looking analysis. The Office of Management and Budget
                        requires regulatory impact analysis before any major new
                        regulation is put into effect. And the Congressional Budget Office is
                        required to “price out” all new legislation. Thus, there are many
                        applications and methods in this prospective area.

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    Chapter 1
    What Is a Prospective Question?

    The use of the PES described in this paper is
    consistent with GAO’s policy on forward-looking
    questions and on the methodology to be used in
    developing recommendations. This policy is set forth
    in the General Policy Manual, chapter 10.0, and in
    chapters 12.10 and 12.18 of the Communications
    Manual. These latter chapters specify, for example,
    the procedures that are to be followed when dealing
    with programs and policies under legislative
    consideration or recommendations asserting the
    possibility of budgetary savings. Particularly relevant
    in the General Policy Manual are the sections on
    formal modeling, economic optimizing, and

    1. How well has the administration projected or
    estimated the future needs, costs, and consequences?
    In responding to such a forward-looking question,
    GAO may need to address issues such as the

•   How well has it anticipated, for example, revenues or
    staff needs or emerging problems?
•   Are the methods for projection sound?
•   Are the data bases reliable and adequate?
•   Are the assumptions explicit?
•   Are they reasonable?
•   Have the projections been overgeneralized?
•   Are there feasible improvements to the procedures or
    the reporting?
•   Are better estimates, or better-reported estimates,

    In the case of repeated or regular forecasts, we may
    have to examine whether the relevant agency
    systematically evaluates their accuracy and, if so,
    whether the error rates are acceptable and without
    bias. Further, when the administration publishes
    claims about the likely consequences of its own

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    Chapter 1
    What Is a Prospective Question?

    proposed activities, we may examine whether claims
    are methodologically sound and properly presented.
    And, when the administration has sought to block or
    prevent action, using projections or estimates of
    future costs or consequences, we may determine
    whether these projections, too, are sound and
    accurately reported.

    2. What is the potential for the success of a
    congressional or administration proposal? In
    answering this type of inquiry, GAO could look at the
    following questions:

•   Given the characteristics of new or amended
    legislation being considered by the Congress, how
    likely is it that a bill will achieve its stated objectives?
•   What features might be modified to improve its
    chances of success?
•   Are there side effects or pitfalls known from past
    experience that could be remedied prospectively?
•   When the administration initiates a new policy or new
    legislation by proposing a set of activities, how likely
    is it that these will work?
•   What changes that might be made before the proposal
    is put into effect would better achieve the intended
•   What unidentified dangers should be considered
    before action is taken?

    3. What are future needs, costs, and consequences? In
    many areas, GAO is asked to anticipate the future in
    analyses such as the costs of future illegal
    immigration, the flow of future legal immigrants, the
    future costs of the AIDS epidemic, military personnel
    needs, and the adequacy of stockpiles of materials
    critical to the national defense. According to our
    policies, we are expected to use state-of-the-art
    methods for making any quantitatively based
    forecasts or projections and to use due professional

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Chapter 1
What Is a Prospective Question?

care in applying qualitative approaches, such as
expert panels. We could check on whether we have
used the technically most solid procedures, fully
considered alternative methods, and applied and
reported properly the ranges of uncertainty inevitable
in any prediction, using approaches such as
sensitivity analyses to test systematically the effects
of different assumptions.

4. What course of action should we recommend as
most likely to succeed in addressing the problems we
identify? Our policies require us to carefully consider
alternative actions resulting from our findings and to
weigh the costs of these alternatives and their
likelihood of success before we present them as
matters for consideration or as recommendations.
This requirement distinguishes GAO from other
congressional support agencies. They follow the
policy analysis approach of presenting options but do
not make recommendations. GAO goes through the
analytic steps and makes its choice of the preferred
solution. Further,

GAO systematically follows up and reports on the
acceptance of the recommendations it makes in its
reports. In this context, procedures for developing
alternatives and selecting recommendations can be
seen as the most crucial part of our work. Have we
used the most methodologically sound procedures for
identifying alternative actions and for making and
documenting the analyses required in our policy and
procedures manuals?

While these illustrations do not exhaust the range of
prospective questions, what they say is that we are
effectively in the futures business, both through the
implications of our own policies and because the
Congress is asking us to make or examine estimates

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Chapter 1
What Is a Prospective Question?

of and projections about the future.2 This may be
expected to continue (1) as the effort required for
members of the Congress to push new legislation
through the Congress and to amend existing
legislation becomes greater, (2) as evaluations of past
programs demonstrate problems that could have been
prevented in existing programs, and (3) as the
methodology and the motivation to get smarter about
the future improve and increase. That is, we have an
important role in helping prevent future problems and
in helping promote greater success before action is
taken and before program actors and stakeholders
become entrenched.

This role complements our mission to report
objectively, but in retrospect, on what is happening
now and on what has occurred in the past. It is quite a
different one, with distinctive methods of its own. As
table 1.2 indicates, retrospective and prospective
methods differ on such features as the source of the
evaluation questions, where we get our information,
and techniques for analyzing the evidence. Each
method has its own requirements and its own
strengths and limitations for our work. Those of the
PES will be discussed in detail in this transfer paper.
The requirements of retrospective methods have been
presented in other transfer papers.

 The Kansas City Regional Office maintains a comprehensive
review and bibliography of all GAO reports involving relatively
innovative methodologies, providing easy access to these earlier
applications, for job planning purposes. This list includes many
reports dealing with forward-looking questions, some of which are
included in our references to help illustrate further the range and
history of this aspect of our work.

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                         Chapter 1
                         What Is a Prospective Question?

Table 1.2: Features of
Retrospective and        Feature               Retrospective       Prospective
Prospective Methods      Source of questions Criteria and          Ideas and
                                             issues in existing    assumptions
                                             programs,             about problems,
                                             regulations, and      probable causes,
                                             policies              and possible
                         Primary sources of    Documents,          Prior research,
                         information           administrative      theory, and
                                               data, interviews,   evaluations; pilot
                                               observations,       or experimental
                                               opinion surveys     tests of proposed
                                                                   approach; expert
                         Primary types of      Qualitative         Simulations,
                         analysis              approaches to       modeling, and
                                               empirical data,     information
                                               quantitative        syntheses in
                                               approaches to       relation to
                                               empirical data,     conceptual and
                                               information         operational
                                               synthesis in        assumptions of
                                               relation to         proposals (PES);
                                               program criteria    Delphi
                                               and issues          techniques;
                                                                   analyses of likely

                         We have already discussed the nature of
                         forward-looking questions, described the types of
                         methodological issues they raise, and summarized
                         when a PES would and would not be appropriate.
                         Subsequent chapters present a definition of the
                         prospective evaluation synthesis, a detailed example
                         of how to carry it out, and some of its variants.
                         Special attention is given to the crucial issues of
                         judging the quality of the information being
                         synthesized and models for aggregating results across
                         many prior studies.

                         Page 16            GAO/PEMD-10.1.10 Prospective Evaluation
Chapter 2

The Need for Systematic Methods for
Answering Forward-Looking Questions

            In doing our work, we should use the methodology
            appropriate to the complexity of the question and to
            the level of effort required by the situation. Either
            overkill or underkill in design would be a mistake in
            job management. The first wastes scarce resources;
            the second fails to meet the need adequately.

            For some questions and some circumstances, the use
            of highly systematic methods of dealing with
            forward-looking questions would be overkill. For
            example, we may be asked about one provision of
            proposed legislation in an area in which we have had
            many years of experience and in which we have
            published reports whose recommendations bear
            directly on the provision. Further, the idea may be
            one among several at early stages of consideration
            and it may be unclear that the legislation will move
            forward in the current session. Here, the evaluator
            might adequately satisfy methodological and
            customer concerns by drawing on our cumulative
            experience to discuss the issue as we have already
            seen it and, subject to our usual reviews for bill
            comments, comment informally on it. That is, we may
            use professional judgment and opinion.

            Where the questions are controversial, far-reaching,
            and sensitive, more systematic methods may be called
            for. For example, our analyses of the savings and loan
            problems, and of various bailout proposals, called for
            more than informal methods, because of the
            sensitivity and long-term consequences of how this
            issue is resolved.

            Among the advantages of using systematic methods
            are the following.

            1. The full range of existing information may be
            efficiently brought to bear on the question. Rather
            than relying, in a somewhat happenstance way, on an

            Page 17         GAO/PEMD-10.1.10 Prospective Evaluation
Chapter 2
The Need for Systematic Methods for
Answering Forward-Looking Questions

individual’s memory, we identify, consider, and apply
the body of available knowledge to answering the
question. Data that were costly to collect in the past
and are still relevant but that might otherwise be
neglected can be used. The risk of overlooking
contradictory evidence may be notably reduced.

2. The degree of confidence we have in our own
answers—whether analyses of other people’s
forecasts, conclusions regarding the success of
proposed legislation, or our own
recommendations—can be stated more precisely than
less-formal methods permit. When we deal with the
future, uncertainty is part of any analysis, no matter
how sound, but the more precisely we state the
degree of uncertainty, the more complete, and the
more useful, our prediction will be. Saying, “We are
95-percent confident that the number of competitively
awarded contracts will increase by between 10,000
and 15,000 for each of the next 4 years” provides more
precise information to a decisionmaker about
likelihood than does the statement “More contracts
will be awarded competitively in the future.”

3. One method for promoting the quality of
prospective work is independent replications. When
we use systematic methods to review other people’s
projections or to make our own, we are better able to
replicate the analyses and thus promote quality. That
is, when independent analysts obtain the same
results, confidence in findings rises. In the physical
sciences, such replication in independent laboratories
is often required before a result is accepted as sound.
However, replication requires precision in describing
and carrying out the analytic procedures. Similarly, in
the social sciences, of which program evaluation is a
part, using systematic methods permits replication
and helps distinguish robust findings from artifacts of
differences in technique.

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Chapter 2
The Need for Systematic Methods for
Answering Forward-Looking Questions

4. Systematic methods can help us follow high-quality
standards of evidence and analysis in documenting
the basis for answers about the future. Much of our
work requires an element of judgment. Prospective
jobs inherently involve a greater degree of uncertainty
than retrospective questions and, consequently, a
greater element of judgment. In all such jobs, we must
be scrupulous in identifying sources of uncertainty
and, consequently, the need for alternatives and
options. However, using systematic prospective
methods can reduce the qualifications we have to add.
Fewer caveats may be necessary if we apply
state-of-the-art methodology.

In short, systematic prospective methods hold great
promise for strengthening our ability to speak well to
emerging issues.

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Chapter 3

Prospective Methods and the
Prospective Evaluation Synthesis
Broadly Defined

             Prospective questions deal primarily with what will
             happen in the future. However, most prospective
             methods rely heavily on information about what has
             happened in the past, primarily empirical and
             evaluative data. Judgments—that is, assumptions and
             interpretations—enter in, particularly when we
             speculate on future conditions or alternative
             scenarios. Methodologically, answers to these
             questions require approaches that meet special
             challenges, compared with retrospective methods.

             For example, almost all evaluations have to take
             context into account if the ability to generalize is an
             issue. In retrospective methods, one approach that
             permits generalization is simple random sampling
             from a properly defined population. Another such
             approach is stratified random sampling, in which
             relevant subgroups are considered, such as urban and
             rural or rich and poor states. Where there is reason to
             expect that the results of a program will depend on
             different circumstances—the economy, the culture,
             human resources—stratified random sampling is
             typically used. For retrospective studies, what is
             relevant is usually clear, and how the characteristics
             of entities we could sample vary is usually known.

             Not so for prospective studies. What the relevant
             characteristics of the future will be, and how entities
             will vary, encompasses a wide range of possibilities.
             For example, whether participants in a proposed
             job-training program will be likely to find employment
             in a given period may be influenced more by overall
             trends in the economy than by instructional or
             targeting nuances. But perhaps economic conditions
             will be relatively unchanged, so that other
             characteristics of the context will be more important
             to consider.

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Chapter 3
Prospective Methods and the
Prospective Evaluation Synthesis
Broadly Defined

Putting this distinction somewhat more technically,
generalizations in retrospective studies are fairly
straightforward, empirically based statements in
which one moves logically from a sample to a
population. Extrapolations in prospective analyses, in
contrast, require one to move logically and
conceptually, as well as empirically, by taking into
account how a particular finding might operate under
varying conditions and situations. We thus have to
make economic and other assumptions explicitly;
otherwise, we are implicitly accepting the
continuation of the present unchanged into the future.
(See Cronbach, 1982, for a more detailed discussion.)

Despite this and other challenges, a set of prospective
evaluation methods has been developed. As table 3.1
illustrates, these include actual, empirical, logical,
judgmental, and mixed approaches.1

 Economists have developed many quantitative methods for
projecting the future, particularly those involving economic
forecasting, modeling, and simulations. These have in common the
specification of a theory (conceptual model in PES terms) of what
is influencing relevant outcomes, the identification of key
assumptions, quantification—on the bases of theory and past
experience—of these assumptions, and running often very complex
quantitative analyses of most likely outcomes under different
assumptions about how the future will be similar to and different
from the present and the past. For example, the Social Security
Trustees Report is based on quantitative models whose key
assumptions include more and less optimistic estimates of
economic conditions. Our policy manuals describe some of these
techniques and suggest appropriate uses. The PES can include the
results of these modeling and simulation studies but differs from
them in its greater reliance on prior empirical work on related
programs in the past or on basic and applied research.

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                      Chapter 3
                      Prospective Methods and the
                      Prospective Evaluation Synthesis
                      Broadly Defined

Table 3.1: Some
Prospective Methods   Type                 Illustrative technique
                      Actual               Experimental tests;
                                           Demonstration programs
                      Empirical            Simulation;
                      Logical              Front-end analysis;
                                           Risk assessment;
                                           Systems analysis;
                                           Scenario building;
                                           Anticipatory analysis
                      Judgmental           Delphi techniques;
                                           Expert opinion
                      Mixed                Prospective evaluation synthesis

                      The prospective evaluation synthesis, or PES, is a
                      new member of the class of prospective methods
                      (Chelimsky, 1988). It was adapted by GAO from the
                      evaluation synthesis in order to answer questions
                      about the future more systematically than informal
                      methods and more rapidly than some other
                      prospective methods such as experimental programs.
                      (U.S. General Accounting Office, 1983) (Appendix I
                      also gives a brief history of the PES.)

                      Conceptually, the PES provides a way in which the
                      logic of evaluation methodology and its procedures
                      can be appropriately used in assessing the potential
                      consequences either of an individual proposal or of
                      alternative and competing policy proposals. It
                      combines (1) the construction of underlying models
                      of proposed programs or actions as developed by
                      Wholey for evaluability assessment with (2) the
                      systematic application of existing knowledge as
                      developed in the evaluation synthesis methodology.
                      (Wholey, 1977) That is, a PES is a prospective analysis
                      anchored in evaluation concepts. It involves logical,
                      conceptual, and empirical analyses, taken in the
                      context of the future.

                      Page 22          GAO/PEMD-10.1.10 Prospective Evaluation
                           Chapter 3
                           Prospective Methods and the
                           Prospective Evaluation Synthesis
                           Broadly Defined

                           As figure 3.1 illustrates, the conceptual analyses
                           results help focus the operational analyses and
                           answer the question, “Logically, should the proposal
                           work?” The operational analyses further scope the
                           search for empirical findings and answer the question,
                           “Practically, could the proposal work?” The empirical
                           analyses can open both new conceptual and
                           operational possibilities and answer the question,
                           “Historically, have activities conceptually and
                           operationally similar to the proposal worked in the
                           past?” Finally, the PES takes into account ways in
                           which the past is and is not likely to be similar to
                           plausible future conditions.

Figure 3.1: the Triad of

                           As noted, the PES can be used either for examining
When the PES Is            an individual proposal or for comparing two or more
and Is Not                 policy alternatives. In examining an individual
Appropriate                proposal, the PES requires a criterion, or a hoped-for
                           good that needs to be made explicit. Developing
                           explicit criteria is a task familiar to GAO evaluators.
                           Nonetheless, it is often difficult, since legislative

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              proposals can result from greater agreement on
              actions than on aims or goals. Assessing two or more
              proposals may be somewhat easier, because the
              points of “common cause” can serve as a proxy for
              the hoped-for good. Further, it is generally simpler to
              make comparative judgments (“Which is better?”)
              than absolute ones (“Is it good at all? How good?”).

The PES and   Additional conditions affect the use of the PES.
Timeliness    Although the PES has the promise of being among the
              most timely evaluation methods, obviously it cannot
              operate instantaneously. While times vary, an analysis
              of two or more bills might require about 3 months on
              the part of at least two evaluators in order to provide
              for adequate reviews of published and unpublished
              literature, consultation with technical experts, and
              the thorough assessment of the resulting information.
              However, a PES may take longer than 3 months,
              especially when the competing legislative proposals
              are quite complex, when there is little prior
              experience with issues, or when most of the literature
              is unpublished.2

              This time constraint indicates that a PES should be
              started as soon as possible after a customer’s inquiry,
              in order to ensure that the assigned evaluators have
              the requisite time for their work. For less-complex
              issues, or situations such as analyses of possible GAO
              recommendations, where a separate report does not
              have to be written, less time may be required. As
              noted earlier, a greater level of effort would be

               The unpublished literature can include reports prepared under
              contract to the government, work in progress that has been
              presented as draft material or in speeches, and other relevant
              material that may not have appeared yet in print. Searching for
              these materials usually involves reviewing federal contracts and
              grants, contacting project managers and principal investigators,
              and canvassing other experts in the field.

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                   allocated to controversial, sensitive, and far-reaching

The PES and Data   Another point affecting timeliness is that when an
Availability       issue becomes extremely popular or extremely
                   controversial in the legislature, it may happen that
                   many different bills on the same subject are
                   introduced within a short time. This can cause such
                   logistical and other problems that a PES may not be
                   the appropriate method. But if this situation should
                   develop in the middle of the PES effort, then the
                   evaluator would either have to resist expanding the
                   scope of the study or obtain an extension of time.

                   As indicated above, the PES relies heavily on the
                   knowledge—basic and applied—already produced by
                   evaluators and researchers. The PES can be used
                   effectively on topics for which a body of relevant
                   literature exists. For some mature issues that have
                   long attracted the attention of evaluators and
                   researchers, the existing literature may be abundant,
                   containing many studies and theories concerning the
                   basic mechanisms involved. For others that are new
                   or have not yet stimulated much investigation and
                   scholarship, PES evaluators may not be able to find a
                   great deal that is relevant.

                   As mentioned earlier, this outcome tells the
                   policymakers that there is little empirical basis for
                   their decisions. They can then judge the merits of
                   moving ahead, not moving forward, or limiting the
                   types of actions they take (targeting, demonstrations,
                   and so on). It may also be an important opportunity to
                   present to policymakers the research and data needs
                   that would have to be filled in order to make firm
                   judgments. The case of the PES that includes
                   recommendations for demonstration, experimental,
                   or pilot projects may, therefore, be relatively frequent,

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                  Prospective Methods and the
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                  Broadly Defined

                  since such approaches can be useful alternatives to
                  across-the-board changes in national policies.

                  In many situations, a full PES would be overkill as we
The PES and the   prepare recommendations. For example, finding a
Recommendations   lack of accepted internal controls or finding a failure
GAO Makes         to report honestly information unfavorable to costly
                  weapon systems leads quite directly to well-supported
                  recommendations. In other circumstances, however,
                  our findings are more complex, our sense of
                  alternatives is broader, the results are more uncertain.
                  In some cases, these could be presented as matters
                  for consideration. In others, particularly those
                  involving controversial, sensitive, or far-reaching
                  conclusions, our recommendations—derived perhaps
                  through other methods—could themselves properly
                  be the subject of a PES.

                  Table 3.2 illustrates some of these circumstances,
                  which include, for example, situations in which the
                  federal role may be relatively complex, our
                  recommendations would pose notable costs or
                  burdens, and major structural or management
                  changes might be involved. In such circumstances,
                  investing some time in a PES might permit us to be
                  even more hard-hitting and convincing and to have a
                  solid effect, leading in turn to greater savings and
                  nonmonetary benefits. These and other
                  considerations about when an evaluator should
                  consider a PES are summarized in table 3.3.

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                              Chapter 3
                              Prospective Methods and the
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Table 3.2: Illustrations of
Where a PES Might             General circumstance Specific example
Strengthen Our                Involves complex          What is the best way for the
Recommendations               federal, state, and local federal government to encourage
                              relationships             state and local governments to
                                                        serve handicapped persons who
                                                        are older and younger than
                                                        regular school age?

                                                       What would be the best strategy
                                                       to strengthen results from federal
                                                       funds in child abuse prevention?
                              Nontrivial costs or      How many Internal Revenue
                              burdens                  Service agents should be added
                                                       to current staff or redirected from
                                                       current tasks to go after
                                                       unreported income not caught by
                                                       computer matching?
                              Major structural or      How should the responsibilities
                              management changes       and roles of the Office of
                                                       Management and Budget and
                                                       other agencies be restructured to
                                                       better identify low-quality
                              Very high national       What are the optimum ways of
                              stakes are involved      dealing with the
                                                       savings-and-loan crisis?

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                           Prospective Methods and the
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Table 3.3: Situations in
Which a PES Should and                            Consideration of PES as a method
Should Not Be                                                     Probably should
Considereda                Situation              Probably should not
                             Data base            High, moderate       Low
                             Proposal             Complexity low or High complexity;
                               complexity         moderate and      little time
                               relative to time   time short or
                               available          moderate; or,
                                                  complexity high
                                                  and time long
                             Proposal             High, moderate       Low
                             Degree of            Moderate, high       Low
                             National stakes      Moderate, high       Low
                             Consequences   Far-reaching               Restricted in
                              of our                                   scope
                             These considerations apply to the PES. Other prospective
                           methods could be useful when it would not be appropriate to
                           do a PES.

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Chapter 4

The PES: Initial Steps

                          As table 4.1 shows, there are six steps in the basic
                          PES approach, three of which closely involve the
                          persons who request the job or are likely to use the
                          results to make decisions—the customer. The six
                          steps are defining the problem, selecting the options
                          or alternatives to evaluate, analyzing the conceptual
                          underpinnings of the selected alternatives, analyzing
                          the operational logic of the selected alternatives,
                          testing the key conceptual and operational
                          assumptions against existing evidence, and presenting
                          the results in relation to the key assumptions.

Table 4.1: Steps in the
Basic PES Approach and    Step                               Persons involved
Persons Involved          Defining the problem               Customer, evaluatora
                          Selecting alternatives to          Customer, evaluator
                          Conceptual analysis                Evaluator
                          Operational analysis               Evaluator
                          Testing key assumptions
                              Check on assumption            Customer, evaluator
                              Test against existing          Evaluator
                          Presenting results                 Evaluator
                           For GAO, the customer is the congressional requester for the
                          job. Other persons helpful at this step might include
                          stakeholders and experts in the field. In the catastrophic health
                          insurance PES, for example, health provider and consumer
                          organizations provided useful input in defining the problem.
                          Input is, of course, received in the context of the usual GAO
                          guidance on ensuring our independence and objectivity.

                          While these steps are essential in using the PES for
                          commenting on proposed congressional or
                          administration actions, they also apply to the analysis
                          of possible recommendations, with two

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                Chapter 4
                The PES: Initial Steps

                modifications. First, generating alternative
                recommendations involves either usual GAO
                procedures or the application of techniques such as
                forecasts, assessment of likely effects, and
                scenario-building. Second, we need to use judgment
                with regard to how extensively we can involve the
                customer in selecting options and in checking
                assumption centrality while maintaining our essential
                independence at this stage of our work.

                In this chapter, we discuss the first two steps shown
                in table 4.1. The others are described in chapter 5. For
                each step, we first present what that step means, why
                it is important, what its role is, and the kind of
                activities that would fulfill the requirements. Then we
                illustrate how to do the step through its application in
                a GAO report. The applications in both chapters
                center on a specific example, a PES conducted on
                competing legislative proposals dealing with the
                problem of teenage pregnancies. (U.S. General
                Accounting Office, 1986b)

Defining the

Detailed        Table 4.2 shows the key elements of this important
Specification   first step. Here the evaluator works with the client to
                draw the target that the proposal is to hit, trying to be
                as clear as possible on the size and nature of the
                concerns that the proposal is intended to solve. In the
                PES, the evaluator is trying to see if the proposed
                program will work to solve not a generic problem,
                necessarily, but a specific one. Thus, a program that
                may be well-aimed at one target may miss another
                widely. For example, many programs can involve
                providing food supplements, nutrition education, and
                health screening. Some, however, may be aimed at

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The PES: Initial Steps

solving the problem of low birth weight babies among
low-income women and teenage mothers; others may
be aimed at promoting age-appropriate progress in
height and weight among preschoolers. Hence, the
pivotal question of this first step: What’s the target?

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                       The PES: Initial Steps

Table 4.2: Step 1:
Defining the Problem   Aspect                        Definition
                       What “defining the problem”   Detailed specification of
                       means rules                   the concern that rules in
                                                     and out what will be
                                                     considered part of the
                                                     problem. This creates the
                                                     “target” to be “hit”
                                                     successfully by the
                       Why this step is important    Different people may define
                                                     an apparently “clear”
                                                     problem broadly or
                                                     narrowly. Unless customer
                                                     and evaluator agree on
                                                     what is to be considered
                                                     part of the problem,
                                                     analyses aimed at
                                                     determining whether
                                                     proposals will work can
                                                     themselves be off-target
                       The role of this step         As the start of the PES, it
                                                     helps determine the scope
                                                     of the work and lays the
                                                     foundation for the use of
                                                     the results
                       Activities that fulfill the   (1) Discussions with the
                       requirements for this step    customer and review of
                                                     hearings (if any) on the
                                                     proposal with regard to the
                                                     size and nature of the
                                                     problem. (2) Independent
                                                     analysis of the evidence
                                                     regarding the size and
                                                     nature of the problem. (3)
                                                     Identification of points that
                                                     require agreement and
                                                     decisions. (4) Discussions
                                                     with the customer and
                                                     others as necessary to
                                                     reach closure on the
                                                     definition of the problem

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               The PES: Initial Steps

Illustration   In 1984, there were about a million pregnancies and
               500,000 births to women under 20. In response came
               bipartisan congressional efforts to increase the
               federal effort in this area. More than a score of bills
               were introduced into the Congress in 1986.

               Concerned about the best way to assess the proposed
               legislation, a congressional requester asked us two
               questions: (1) How effective had prior efforts been to
               address the problem? (2) What implications for
               structuring future legislation might be drawn from
               existing knowledge about teenage pregnancy?

               The first step of the PES was to clarify the problem in
               order to focus the scope of the PES properly. In this
               example, the GAO staff determined that “teenage
               pregnancy” per se was not the problem, because
               policymakers were not concerned about births to
               married women under 20. Rather, two problems were
               posed in debates: (1) births to teenagers without the
               resources to support themselves or their children and
               (2) the negative health and social consequences for
               both mothers and infants associated with births to
               unwed and poor teenagers.

               Faced with a subject that has been defined in more
               than one way, one can, of course, decide to restrict
               the focus of the PES to one definition or another.
               Following discussion with the customer, we chose to
               deal with both problems. In effect, this decision
               meant enlarging the scope of the PES to a review of
               the literature addressing both the prevalence of
               teenage motherhood and the consequences of that
               prevalence. Fortunately, the literature on teenage
               pregnancies was not ordinarily restricted to one or
               the other issue: most sources contained information
               relevant to both. Certain topics that could have been
               included with the teenage pregnancy problem had
               received little or no attention. The excluded topics

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                  The PES: Initial Steps

                  also helped define the policy space.1 For example,
                  congressional concern was expressed not about all
                  pregnancies but only about those resulting in live
                  births. Ignored in the discussion were the estimated
                  50 percent of the teenage pregnancies terminated by
                  spontaneous or induced abortion.2 Furthermore,
                  interest centered largely on the pregnant women and
                  not on the presumably teenage males who had
                  impregnated them.3 Whether correct or not, the
                  implicit legislative definition of teenage pregnancy in
                  1986 was as a problem primarily affecting the young
                  women and their children.

                  Another aspect of defining the problem centered on
                  who is to be considered a teenager. Clearly, women
                  18 or younger were included by everyone. But some
                  discussions included all women under 25, while
                  others restricted the definition to persons under 20.
                  By agreement with the customer, we focused
                  primarily on women 20 or younger.

                  The PES does not generate proposals at the
Selecting         beginning: that is, a proposal has already been made,
Alternatives to   and the issue is whether it is likely to hit the target, as
Evaluate          we said earlier. Not all proposals are good or equally
                  good candidates for a PES, however. This step does
                  two things. First, it screens out proposals in which a
                  PES is not the right evaluation tool. Perhaps, for

                   “Policy space” is within the boundaries of politically acceptable
                  policies. Thus, the set of policies enclosed within the policy space
                  of any given period consists of all the policies that are acceptable to
                  one or another of the principal political partisans.
                   It seemed obvious that a policy of promoting induced abortions as
                  a solution to adolescent pregnancies was clearly outside the 1986
                  policy space.
                   There was some concern in one proposal with teenage fathers, but
                  this was never an important center of attention, although the
                  problem could also be phrased as lack of family formation or of
                  responsibility on the part of the young men. A PES could, at this
                  stage, compare alternative target definitions in terms of precision,
                  Page   34 and so on.GAO/PEMD-10.1.10 Prospective Evaluation
Chapter 4
The PES: Initial Steps

example, the proposal seems to change daily or
perhaps we have already reviewed similar proposals
and can quickly draw on our corporate knowledge to
provide comments on likely success.

Second, of the proposals for which the PES is the
right evaluation tool, this step selects the optimum
ideas for review. “Optimum” can include the
consideration of a variety of factors. One is, of course,
the specific interest of the customer. Others may
include variations among proposals in cost, target
groups, or the governmental means
proposed—regulatory, categorical, tax policy, block
grant. For example, proposals to provide long-term
nursing care to the elderly could vary notably in cost,
depending on such factors as the copayments
required, the conditions covered, and the duration of
care authorized. Some proposals could cost millions
annually; others, billions. Selection on the basis of
variation among the proposals could in turn reflect
such factors as maximum ranges, special interests,
and similarity to existing pilot work. The PES should
be explicit about the basis to be used, because the
choice made at the end of this step notably affects the
scope of the work and the utility of the results. Table
4.3 describes this step.

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                            The PES: Initial Steps

Table 4.3: Step 2:
Selecting Alternatives to   Aspect                        Definition
Evaluate                    What “selecting policy A PES usually begins with a
                            alternatives to evaluate” specific proposal whose likely
                            means                     success is to be evaluated. What
                                                      is actually evaluated may differ,
                                                      however, as a result of activities
                                                      conducted during this step.
                                                      “Selection” means that at the end
                                                      of the step, the proposal to be
                                                      assessed will have been
                                                      determined and alternatives, if
                                                      any, will have been selected
                            Why this step is              Not all proposals are good
                            important                     candidates for a PES. And
                                                          among the good candidates, not
                                                          all may be equal in optimum use
                                                          of time: it may be more useful to
                                                          policy to analyze some proposals
                                                          rather than others
                            The role of this step         It helps ensure that the evaluator
                                                          will not be wasting time, and it
                                                          gives the analyses optimum value
                            Activities that fulfill the   (1) Identification of the politically
                            requirements for this         viable alternatives. (2) Screening
                            step                          to be sure there are no reasons,
                                                          such as rapidly moving changes
                                                          or an adequate body of analyses
                                                          of similar prior proposals, to
                                                          reject these as PES candidates.
                                                          (3) Examination of the proposals
                                                          that would be optimum to review
                                                          in depth through the PES,
                                                          according to criteria such as
                                                          maximum differences in proposal
                                                          characteristics. (4) Selection of
                                                          the PES proposals

Why the PES Begins          For any problem, a large number of potential policies
With Existing               and programs may be relevant. However, assessing
Options                     the full range of possible alternative policies is not the

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Chapter 4
The PES: Initial Steps

concern of a PES. The PES task is constrained by two
principles. (1) The task must be restricted to one that
can be examined by posing the evaluation question,
“Is there evidence that a particular program or policy
will or will not be likely to meet its stated objectives?”
(2) The PES begins with the options that
policymakers are already considering in order for
PES findings to be useful to them. Thus, this is a
process that starts with the alternatives under
consideration, then looks for any evidence
concerning the potential efficacy of those
alternatives, and, only if necessary, generates other

It is important to understand the implications of
centering the PES on existing alternative policies.
Another way to proceed would be to make a
comprehensive review of all the research and
evaluation literature relevant to the problem in
question, attempting to infer the implications it has
for policy and designing alternatives ourselves.
However, this alternative is rejected in the PES
method for two main reasons.

First, there may be only a loose fit between research
findings and policy. It is possible for two reviewers to
draw different policy implications from the same
research evidence.4 Unless some obvious logical error
has been made, neither reviewer would be correct
and neither would be incorrect in his or her

 For example, given the existence of a large number of teenage
pregnancies, one policy alternative would be to conduct campaigns
to convince teenagers to have abortions. Another policy that fits
the data is to conduct campaigns stressing sexual abstinence
among teenagers. Still a third would be to provide cash bonuses
and ongoing subsidies to men who would marry and support
pregnant teenage women, since the underlying problem could be
conceptualized as lack of family formation. None of these policies
is “incorrect” in the sense of misinterpreting the basic finding of the
existence of a widespread problem, but, also, none would have
been relevant to the policy formation process in 1986.

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               Chapter 4
               The PES: Initial Steps

               projection of policy implications. But contradictory or
               even equivocal recommendations are difficult to use
               in decisionmaking.

               Second, the PES approach allows the reviewer to
               make definite statements that are subject to
               verification. The outcome of a PES review is an
               assessment of whether the policy or policies under
               consideration are supported or not supported by the
               existing evidence. If a PES concludes that proposal A
               is justified by the evidence and some other
               commentator asserts that it is not, then it is possible
               to compare the analytic procedures used by each of
               the disagreeing parties to determine the position that
               is justified by the research evidence.

               What about a situation in which none of the options
               already on the table is likely to work? To be
               maximally helpful, the PES relies on prior research
               and evidence as a way of refining the policy options.
               If the prior research did not support the options
               under consideration, then the PES would try to
               identify the policy options that were within the most
               realistic range of the research, when the questions
               were considered at appropriate levels of complexity.
               For example, proposed legislation on housing for
               physically handicapped adults might focus on
               increasing independence for single persons, but the
               literature might consistently place greater emphasis
               on group homes or family units.5

Illustration   As stated earlier, the PES is intended to weigh how
               closely the research and evaluation evidence supports
               a proposed policy or one or another of several

                Care must be taken in using prior research to assess its technical
               quality, including the independence and objectivity of the
               researcher. See our discussion on recognizing threats to objectivity
               in our transfer paper entitled Case Study Evaluations (U.S. General
               Accounting Office, 1987c).

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Chapter 4
The PES: Initial Steps

alternative policies. In the case of the teenage
pregnancy project in 1986, several alternatives could
be compared. Twenty-two separate bills regarding
teenage pregnancy had been introduced in the
Congress, twice the number proposed the year before.
For the PES, which had to be completed within 4
months, the selection of proposals to consider took
on some importance. Clearly, full consideration of all
22 proposals was out of the question.

To aid in the selection of proposals to assess, GAO
staff performed a content analysis of each program
proposal, listing its program requirements, including
such items as criteria for client eligibility, allowable
and required services, and any required administrative
arrangements. (U.S. General Accounting Office,
1982) This information was presented in tabular form
to facilitate identifying the elements that were similar
and those that were different across proposals and
how each bill resembled or differed from the others.

With a few exceptions, most of the 22 congressional
bills proposed national programs of assistance
services exclusively for pregnant and parenting young
women. However, the bills differed on the scope of
the services to be provided, the types of clients who
would be served, and the administrative and financing
arrangements that would be required. Therefore,
rather than attempt to assess the feasibility and
promise of all possible program options, the decision
was made, in consultation with the customer, to focus
the PES on those apparently key, congressionally
relevant dimensions of difference between the
proposals—that is, the choices presented to the
Congress regarding scope of services, clients, and
administrative arrangements. Picking alternatives that
differed widely also would help in the evaluation of
other proposals that differed along the same

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Chapter 4
The PES: Initial Steps

In order to further narrow the focus of the PES, GAO
staff, again in consultation with the customer,
selected two proposals that embodied these choices
by differing substantially on each of these key
dimensions.6 The first proposal was targeted to
pregnant and parenting teenagers, flexible regarding
the services that should be provided, and
administratively straightforward. Grants would be
provided directly to local agencies that would design
and deliver services. In contrast, the second proposal
was more broadly targeted to include economically
disadvantaged women up to age 25, was highly
prescriptive about services to provide, and was
administratively complex, requiring coordination with
five other federal programs. This bill also included a
proposed program for preventing teenage pregnancy,
permitting the PES to address both of the problems
for policymakers that had been identified at the start.

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Chapter 5

The PES: Middle and Final Steps

                   After narrowing the focus of the problem, we have the
                   remaining tasks of analyzing the chosen bills in terms
                   of conceptual and operational models of the proposed
                   programs; identifying from those models the target
                   populations and the program features of interest;
                   selecting the appropriate evidence; arraying that
                   evidence against the models to assess whether these
                   proposed programs are likely to meet their stated
                   objectives; and reporting the results.

The Conceptual

Underlying Logic   The key elements of this step are presented in table
                   5.1. At this point, the evaluation aims at revealing the
                   underlying logic of the proposal: why, in theory, the
                   proposer thinks it will work. For example, a proposal
                   aimed at reducing urban congestion by subsidies for
                   satellite location of offices and businesses probably is
                   based on the assumption that a dispersion of people is
                   possible and desirable and that for a given
                   community, the primary centralization comes from
                   commercial or governmental requirements. A
                   proposal aimed at reducing urban congestion by
                   increasing mass transit and reducing individual
                   parking facilities probably is based on the
                   assumptions that dispersion of businesses attracting
                   people centrally is not possible or desirable and that
                   what will most motivate people to use mass transit is
                   aversion to high parking-lot prices and having to walk
                   long distances from parking lots to businesses,
                   relative to cheaper, more readily accessible mass

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                      Chapter 5
                      The PES: Middle and Final Steps

Table 5.1: Step 3:
Conceptual Analysis   Aspect                        Definition
                      What “conceptual analysis”    Identification of the
                      means                         assumptions, beliefs,
                                                    values, and theory
                                                    underlying the proposal:
                                                    why, in principle, it is likely
                                                    to work or not work
                      Why this step is important    Two reasons. First, it helps
                                                    set up criteria for figuring
                                                    out what prior research or
                                                    program evaluation is
                                                    relevant: it is the research
                                                    on the underlying theories
                                                    or the program whose
                                                    underlying assumptions
                                                    were similar. Second, this
                                                    step can identify gaps (or
                                                    strengths) in logic that
                                                    could lead to uncertainty
                                                    about program success
                      The role of this step         In scoping, this step
                                                    increasingly targets the
                                                    research that will and will
                                                    not have to be examined,
                                                    and it increases the
                                                    efficiency of the job
                      Activities that fulfill the   Content analysis of the
                      requirements for this step    proposed bill or idea.
                                                    Graphic techniques are
                                                    helpful in efficiently
                                                    displaying the conceptual
                                                    models and checking the
                                                    accuracy and
                                                    completeness of our
                                                    interpretation. Can be
                                                    supplemented by
                                                    interviews with sponsors of
                                                    the proposals or
                                                    academicians who have
                                                    worked on the ideas

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               Chapter 5
               The PES: Middle and Final Steps

               Making the underlying assumptions or beliefs as
               explicit as possible helps identify gaps in the logic and
               helps focus the subsequent literature search on
               relevant prior research or program evaluations.1 In
               the urban congestion example, the literature in the
               first instance might focus on evidence regarding the
               dispersion assumption and factors affecting business
               relocations. The second instance might focus our
               attention on research on individual incentives and
               disincentives involving money, convenience, safety,
               and so on in relation to using mass transit versus
               individual cars.

Illustration   To assess both the promise and the feasibility of the
               two teenage pregnancy bills, it was necessary to
               break them down into components that could be
               addressed as subquestions. This required analyzing
               the texts of the two bills to develop two types of
               model for each proposal: (1) a conceptual model and
               (2) an operational model. The strategy here was

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similar to that of developing an evaluation design,
except that a PES reviews existing evidence instead
of collecting new data.

The conceptual models would answer the following
questions: What was the problem to be addressed?
What was the treatment? (Or what actions would be
brought about by the program?) And what was the
intended outcome of those actions? Figures 5.1, 5.2,
and 5.3, from GAO’s report, contain the results of that
disaggregation. (U.S. General Accounting Office,
1986b) These models helped determine the previously
studied programs that should be considered similar to
those proposed and the outcomes that should be
examined when judging their effectiveness. As can be
seen from figure 5.1, the first bill had the objective of
reducing the number of unintended repeat
pregnancies, while the second bill, whose structure is
shown in figures 5.2 and 5.3, articulated a fairly
detailed theoretical model. It proposed to aid young
mothers to avoid welfare dependence by allowing

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                          them to complete school and gain employment and,
                          thus, the bill specified additional intermediate

Figure 5.1: Underlying
Conceptual Model of the
First Bill

                          Source: U.S. General Accounting Office, Teenage Pregnancy:
                          500,000 Births a Year but Few Tested Programs,
                          GAO/PEMD-86-16BR (Washington, D.C.: July 1986), p. 16.

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Figure 5.2: Underlying
Conceptual Model of
Program a in the Second

                          Source: U.S. General Accounting Office, Teenage Pregnancy:
                          500,000 Births a Year but Few Tested Programs,
                          GAO/PEMD-86-16BR (Washington, D.C.: July 1986), p. 17.

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Figure 5.3: Underlying
Conceptual Model of
Program B in the Second

                          Source: U.S. General Accounting Office, Teenage Pregnancy:
                          500,000 Births a Year but Few Tested Programs,
                          GAO/PEMD-86-16BR (Washington, D.C.: July 1986), p. 16.

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The Operational

Underlying        The operational model of a proposed program shows
Operations        how to accomplish the goals of the program. Like the
                  conceptual model, it is constructed by a careful
                  textual analysis of the legislation, but it answers the
                  following question: Who is to be served, by whom,
                  and under what financial and operational
                  arrangements or constraints? An operational model
                  defines the target populations, the intended service
                  providers, the funding sources and amounts, and the
                  administrative structures that should be the focus of
                  the PES.

                  The details of the fourth step—operational
                  analysis—are described in table 5.2. Here the
                  emphasis is not on the “why” of the proposal. It is on
                  the “how” of the proposal: how the proposed program
                  would be carried out and how it would operate. The

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methods of operations research come into play in this
step. The proposals are analyzed to determine who is
doing what, when, and under what circumstances to
whom in order for the proposal to be carried out. This
step can identify the operational complexities (or
simplicities) in the proposal, the number of
decisionmakers, and how contingent the final results
will be on the agreement and coordination of many
(or relatively few) actors.

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Table 5.2: Step 4:
Operational Analysis   Aspect                        Definition
                       What “operational analysis”   Identification of the
                       means                         mechanics of the proposal:
                                                     how it is supposed to be
                                                     carried out
                       Why this step is important    Two reasons. First, it sets
                                                     up criteria for determining
                                                     the relevant prior research
                                                     or programs or the prior
                                                     experience with operations
                                                     similar to those of the
                                                     proposal. Second, this step
                                                     can also identify gaps (or
                                                     strengths) in the proposed
                                                     procedures that could lead
                                                     to more or less certainty
                                                     about program success
                       The role of this step         It sets limits within which
                                                     the search for relevant prior
                                                     research or program
                                                     evaluations takes place,
                                                     increasing job efficiency
                                                     and completeness
                       Activities that fulfill the   Operations analysis of the
                       requirements for this step    proposal. The techniques
                                                     of operations
                                                     research—using the
                                                     content of the proposal to
                                                     identify the design
                                                     elements- -are appropriate.
                                                     Graphic presentation of the
                                                     operation helps check the
                                                     accuracy and
                                                     completeness of our
                                                     interpretation. Interviews
                                                     with proposal sponsors or
                                                     developers provide final
                                                     assurance of the
                                                     operational model’s quality

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The analysis in itself can reveal likely sources of
success or failure for the proposal: gaps, for example,
in authority for making decisions or assumptions
about the availability of resources other than those to
be provided directly through the proposed program.
The operational analysis also serves another function:
it focuses the literature review on the relevant
operational issues that could affect the success or
failure of the new program. Finding, for example, that
the operation of one proposal would require
establishing local stakeholder groups while that of the
competing proposal would involve using elected
officials would turn attention to relevant prior
experience of the efficiency and effectiveness of these
contrasting modes of program management and

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Illustration   Figure 5.4 shows the operational model constructed
               for the second teenage pregnancy bill.

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Figure 5.4: Underlying Operational Model of Program B in the Second Bill

                                                              (Figure notes on next page)

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                    Source: U.S. General Accounting Office, Teenage Pregnancy:
                    500,000 Births a Year but Few Tested Programs,
                    GAO/PEMD-86-16BR (Washington, D.C.: July 1986), p. 19.

Testing the Model

Two Substeps        Testing the model involves two substeps. The first
                    substep—checking the centrality of the assumptions
                    to be examined in depth—means reviewing with the
                    customer the assumptions selected as the focus of the
                    review of prior evidence. The conceptual and
                    operational models usually involve many steps, and it
                    may not be valuable to delve into them all. The

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evaluator selects those that seem to be most pivotal
or to offer the most useful contrasts between
competing proposals. Discussion with the customer
(or the developers of the idea or knowledgeable
academic sources) is a final check that the best points
of entry into tests of key assumptions have been

The second substep—testing key assumptions against
existing evidence—is summarized in table 5.3. This
step uses the evaluation synthesis methodology but
with two differences. The first difference is that what
is relevant has been determined through the process
of specifying the conceptual and operational models
and through checking the importance of the
assumption to the customer. A second difference is

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                              that the evaluations are synthesized with respect only
                              to the chosen assumptions.

Table 5.3: Step 5: Testing Key Assumptions Against Existing Evidence
Aspect                                    Definition
What “testing key assumptions against        A complex body of evidence from prior
existing evidence” means                     research and program evaluation is
                                             collected, and the key conceptual and
                                             operational assumptions are compared
                                             with the findings from prior studies to
                                             determine the likelihood of new program
Why this step is important                   The conceptual and operational analyses
                                             can reveal gaps in logic that are likely to
                                             affect program success. This direct test
                                             against prior experience, however, is the
                                             major criterion for deciding whether the
                                             idea will work. If relevant prior research
                                             and experience indicate that the key
                                             assumptions have worked in the past,
                                             then, if conditions are similar, they are
                                             likely to work in the future (similarly, if they
                                             have not worked in the past and conditions
                                             are to work in the future)
The role of this step                        It completes the triad of analyses
                                             (conceptual, operational, empirical) to give
                                             a conclusion on the proposal’s success
                                             that is as solid as possible
Activities that fulfill the                  (1) Complete identification of relevant prior
                                             research and program evaluation, (2)
                                             assessment of the quality of this evidence,
                                             (3) synthesis of credible findings. The
                                             evaluation synthesis method is applied.
                                             Systematic tabular or graphic comparison
                                             of the evidence against each key
                                             conceptual or operational assumption aids
                                             the efficiency and completeness of this
                                             analysis. Thus, techniques of meta-
                                             analysis and multiple case study
                                             comparisons are applicable

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In table 5.3, step 5 is described as completing the triad
of analyses. As noted earlier, a central methodological
point in the PES is that the results of three different
types of analyses— conceptual, operational, and
empirical—are all compared and otherwise taken into
account in reaching conclusions, thus strengthening
what can be said with some confidence about the
future. When all three approaches give the same
answer, we can be more confident about its
soundness. When they differ, as seen from
conceptual, operational, or empirical perspectives, we
must qualify our results in terms of that lack of
reinforcing agreement. Finally, we need to consider
ways in which the future may differ from the past,
identifying, for example, more or less optimistic
scenarios for relevant factors. Where the future is
likely to be similar to the past on key dimensions, we
can have more confidence about the appropriateness
of the PES to judge the likely success of proposals. As
the scenarios differ from past or present experience,
our certainty necessarily decreases, although we can
still specify conditions under which a proposal is
more or less likely to work.

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Illustration        The review of evidence in the teenage pregnancy
                    example we are following started with a basic
                    question: How many people would be eligible for the
                    programs in the proposed legislation? This was a
                    relatively easy question to answer because of the
                    excellent demographic data collected by the Bureau
                    of the Census and the National Center for Health
                    Statistics concerning the number of teenage women
                    at present, in the past, and in the near future, as well
                    as birth statistics. Less definitive data were available
                    on births by socioeconomic level, although several
                    surveys were the basis for our estimates. The next
                    sections give further detail for the illustration.

Estimating Target   Good estimates of the size of the target population for
Population Size     a proposed program are important for projecting

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program costs. However, the target population is not
identical to client population, since few programs are
ever able to reach all the eligible members of a target
population. In general, the more complex the
eligibility requirements are, the less precise the
estimates of client participation can be. An important
data source can be experience with similar existing
programs. If the clients of an existing program are
identical (or nearly so) with the target population of
some proposed program, a good basis for such
estimates can be the existing program’s current
number of participants. For example, data from states
with catastrophic illness insurance programs
provided important insights for the PES on the
proposed national system. More usually, it is
necessary to synthesize population estimates,
combining numbers from census and administrative
data, for example, with information from population
surveys and research data on the degree of
association between eligibility characteristics.

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In this illustration, no existing program served all
pregnant and parenting teenagers. It was necessary to
rely on published tables from the National Center for
Health Statistics on the characteristics and numbers
of women giving birth each year by age, marital
status, years of school completed, and number of
previous births. It was possible to add up the number
of first births to women under age 18 over several
years to calculate the number of young unmarried
mothers who constituted the target population.
However, this target population is too inclusive, since
some of the young mothers are not poor and, hence,
would be ineligible for program participation under
the first proposal.

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Unfortunately, the National Center for Health
Statistics collects no information on the incomes of
mothers. To estimate the number of poor young
mothers required using sample survey data and
applying survey findings to the vital statistics. Of
course, the potential client populations of proposed
programs are always problematic. Clients should not
exceed in number the total target population, but
participation rates can vary considerably, as
suggested earlier.3

Some information on participation rates can be
obtained by examining existing programs of a similar

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nature. The next task in the PES was to identify the
existing federal programs with related objectives and
target populations. This is important for several
additional reasons. First, there is always an implied
alternative to the proposals being considered, and
that is the status quo, consisting of all the federal
programs already in place. Second, in this instance,
information on existing programs would also address
the feasibility of both the proposed coordination of
existing services and the proposed funding level.

For example, if a proposed program relies on
coordinating services provided under another

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program or programs, whether those services are in
fact available becomes crucial information. It is
crucial because if the services funded by these other
programs are not available, or if the providers are
already operating at capacity and cannot take on new
clients, then the new program has to find another way
of providing those services, and it will need additional
funds to provide them. Further, if existing services
were apparently underutilized, a new program might
not be needed.

The review of existing programs provided little
information on what could be expected as

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                      participation rates in either of the two proposed
                      programs. The main reason for this disappointing
                      outcome was that the existing programs were, with
                      one exception, not exclusively targeted at teenage
                      pregnancies but included other target groups as well.

Finding the Studies   The next task was to conduct a search for all studies
                      published in the recent past (5 years, in the
                      illustration) that evaluated pregnancy prevention
                      programs and comprehensive service programs for

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pregnant and parenting young women.4 The search
included formal publications, such as professional
journals and monographs, as well as computerized
data bases, usually containing bibliographic citations,
4              and informal
  Publication dates   in journals (or  so-called
                                   can follow         fugitive)
                                               the time   of data collection
by several years. including
                    The studies reports
                                  covered up oftolimited
                                                   a decadecirculation
                                                              of research
and   monographs.
previous   to the time ofItthe
                                     This timeimportant        that every
                                                 restriction recognizes
that applied
effort         social research
         be made       to obtainhascoverage
                                     only recentlyof been   used category
                                                      the last    extensively
in the evaluation of programs and that the credibility of remote
as  wide    as  possible,    since   informal      publications
data is slight for reason of age alone. For example, data on the      often
contain     the  latest   studies,   and    to collect
effectiveness of the Great Depression programs, such as theand   note
negative     findings, Corps,
Civilian Conservation      sincearestudies   showing
                                      not likely           positive
                                                  to be viewed    as relevant
to similarare
results     contemporary
                more likely  programs.
                                 to be However,
                                         published   forthan
                                                         some those
      restrictions may be much looser. For example, in a PES on job
training, studies that are a decade or two old may not be seen as
irrelevant, especially if studies over time are quite consistent in
their findings.

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To obtain information on all relevant evaluation
studies, it is usually necessary to rely on personal
contacts with knowledgeable persons. This can
normally be accomplished by sending out lists of
publications already located and asking for the list to
be supplemented by other publications known to the

In this case, all the studies—whether containing
outcome evaluations or not—were reviewed for
analysis of program costs, their sources of funding,
and implementation problems. The information on
where individual projects gained their funds also
augmented the information on existing programs and
services collected earlier on the federal level. Articles
about program failures can provide invaluable
information that gives balance and perspective to the
information gained from successes. For example, they
may give clues as to the staff, public relations, client
recruitment, or support services required for the
proposed programs to operate as intended.

Special attention was paid to publications containing
outcome evaluations. Each publication was read
carefully to ascertain how closely the programs in
question resembled the proposed programs, and a
succinct summary of each program was prepared.
The outcome variables used in the evaluation were
noted separately, particular attention being paid to
the quality of the “impact assessment” data. The end
result of this careful examination was a profile for
each evaluated program, recorded in tabular form,
containing the crucial information on program
description, outcomes, and ratings of data quality.
Appendix III gives an example of one such profile.

As mentioned earlier, it is important to bring to bear
on the literature the same conceptual framework used
in examining the proposed programs. For each article

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                     describing a program and its evaluation, a profile
                     form was filled out, characterizing that project’s
                     clients, services, and administrative arrangements.
                     The categories were the same as those developed in
                     the analysis of the two legislative proposals, in order
                     to ensure that the derived information was directly
                     relevant to the consideration of the proposed

Quality Assessment   The most technically demanding aspect of the review
                     of each evaluation was assessing the quality of the
                     information. Since this task is essentially identical to
                     that confronted in the evaluation synthesis, GAO staff
                     borrowed from criteria employed in previous
                     syntheses. Each evaluation outcome, as defined by
                     the conceptual models of the programs being
                     examined, was treated separately. The evidence on
                     each objective was rated separately. An evaluation
                     might provide evidence of adequate quality on one of
                     the outcomes of interest but not on another, because,
                     for example, of the use of different data collection
                     methods. Other outcomes that were not of direct
                     concern in the conceptual models of the programs
                     under scrutiny in the PES were also noted, along with
                     assessments of the quality of the evaluation evidence

Criteria             The quality-rating criteria used in the assessment of
                     effectiveness evidence have to be tailored to some
                     extent to the issues involved in the PES. Nevertheless,
                     the criteria are largely the same from PES to PES. In
                     this case, criteria centered primarily on the internal
                     validity of the research design used in arriving at

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effectiveness estimates.5 Most of the evaluation
studies had used longitudinal comparison group
designs, making the composition of the comparison
group critical. (Appendix II presents more detail on

The criteria included (1) appropriateness of the
comparison (or control) group; (2) sample size
adequacy, including attrition among clients and
comparison group; (3) standardization of data
collection, including measures of data reliability;
(4) validity of measures used to represent outcome
variables; and (5) appropriateness of statistical
methods used, especially those used to enhance the
internal validity of effectiveness estimates, by testing
for competing explanations of estimates.

The assessment of data quality requires some training
in evaluation design, measurement, and statistics as
well as some understanding of the substantive area.
Several readings are often required. For example,
sometimes the fact that there is anything wrong with
a particular measure of a variable is not obvious until
another study has been examined that is more careful
and accurate in its measurement strategy. It may

 Internal validity refers to the attribution of cause and effect;
external validity, to the ability to generalize. An “ideal” design
would offer strong evidence that effects, if any, stemmed from the
program (or event being studied) and would be obtained from
groups and in situations as similar as possible to the whole range of
circumstances in which the program was being applied. Further,
this ideal design would be appropriately sensitive, able to detect
effects of a size believed worth the costs of the program. Some
experts believe the controls necessary for internal validity severely
limit external validity, and they argue that for policy purposes,
external validity, with its implications for extrapolation, is most
important in judging quality. Other experts are more sanguine
about optimizing both or place heavier emphasis on internal
validity. We thought the question with top priority for this
particular PES was evidence of any effects, and so we focused on
that aspect of design. For some other PES, different criteria might
be weighted more heavily, a point discussed in more detail in
appendix II.

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              often be necessary to read the set of evaluation
              studies several times before a final quality reading can
              be arrived at.

Reliability   As in other rating tasks, it is necessary to test the
              reliability of the ratings (that is, their replicability, or
              likelihood that our reviewers will reach the same
              rating conclusions) by ensuring that there will be at
              least two readers for at least a subset of evaluation
              studies. If a subset is used, the reliability check
              ratings should be done early, midway, and late in the
              coding process to avoid rater-drift and general
              fatigue. Discussion among raters concerning their
              disagreements on the subset often brings to light
              critical characteristics of studies that were not
              immediately discerned.

Aggregation   Although it is possible to arrive fairly easily at a
              reliable and credible rating for each criterion, arriving
              at an overall quality rating is usually more difficult.
              Much of the problem encountered in developing
              overall assessments for the teenage pregnancy study
              arose because many reports did not provide
              information with which to judge the adequacy of the
              evaluation on one or more of the criteria. In the
              absence of direct evidence, it is possible to judge the
              evidence only questionable, unless some other piece
              of information suggests that the absence of
              information stems from some serious flaw.

              In addition, many evaluation studies provide data on
              several evaluation outcomes, each outcome varying in
              the quality of evidence presented. It would be a
              mistake to discount entirely a study that contains an
              acceptable evaluation of one outcome and a poor
              evaluation of another. For these reasons, rather than
              overall quality ratings for each evaluation study, each
              outcome was presented separately along with quality
              assessments of each outcome.

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Presenting the

Product Type     Presenting the results of a PES differs from
                 presenting the results of an evaluation synthesis. In a
                 PES, the underlying conceptual and operational
                 models have to be identified, the key assumptions
                 have to be highlighted, and the evidence has to
                 summarized in relation to these assumptions. In
                 contrast, an evaluation synthesis arrays the evidence
                 in relation to the questions to be answered, and the
                 underlying models need not be explicated. Table 5.4
                 summarizes the elements of step 6.

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Table 5.4: Step 6:
Presenting Results   Aspect                         Definition
                     What “presenting results”      Presentation of the
                     means                          conceptual and operational
                                                    models (usually in graphic
                                                    form) and of the results of
                                                    the comparison of key
                                                    assumptions and evidence
                                                    concisely and clearly
                     Why this step is important     The PES involves an
                                                    uncommonly detailed
                                                    analysis of a proposal. The
                                                    credibility of the results
                                                    depends in part on the
                                                    reader’s being able to
                                                    follow the PES procedures
                                                    easily and to see in detail
                                                    how the findings have
                     The role of this step          Promoting credibility and
                                                    making our conclusions as
                                                    simple, clear, and
                                                    accessible as possible
                     Activities that fulfill the    Development of
                     requirements of this step      appropriate graphics and
                                                    tables; preparation of
                                                    necessary technical
                                                    appendixes (for example,
                                                    details on procedures used
                                                    to rate the quality of prior
                                                    evidence and to aggregate

                     Table 5.4 emphasizes the value of tabular and graphic
                     techniques. The result of a PES might look more like a
                     briefing report than a chapter report. This would vary,
                     of course, in terms of length, depth, whether or not
                     recommendations are provided, and our other usual
                     criteria for deciding on product type.

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Illustration   The results of outcome evaluations are typically
               presented in tabular form, as shown in table 5.5,
               where some of the findings from the teenage
               pregnancy PES assessment are presented. Table 5.5
               was designed to draw the reader’s attention to several
               different things. Across the top are the explicit
               objectives of the legislation plus some others that
               were found to be important in the field. Along the side
               are program types generated by clustering studies
               according to similarity with regard to the services
               they provided. In the body of the table are the
               descriptions of the studies’ comparison groups and
               the results, expressed as whether the program group
               “did better” than the comparison group at a
               statistically significant level. The boxes represent
               findings we considered to be most methodologically
               credible. All this information was transcribed from
               the rating sheets.

               A summary table such as table 5.5 provides
               information on how many studies addressed each
               particular outcome, how much of those data are
               credible, and the types of programs that had effects
               compared to other conditions or programs. The
               information is presented in narrative rather than
               numerical form. While this was an appropriate way to
               present the findings, an alternative would be to report
               effect sizes. Where there are quite a few studies with
               relevant results—and particularly where the
               programs’ clients can be grouped by factors such as
               age, race, education, and family income, which would
               be expected to influence the outcome variables—a
               quantitative presentation can be efficient and

               Note that in table 5.5, comparison groups are
               described in detail. This is also critical information,
               because some evaluations compared the program to
               nothing more than ordinary prenatal health care,

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while other studies compared their program with one
that was only slightly different from it. The presence
and absence of effects under these types of test
condition are thus difficult to assess. That is, a
high-quality test of a program includes the essential
elements of a high treatment strength and a strong
basis for causal attribution. This point became a
conclusion of our illustrative PES: few programs had
been adequately tested, a wide variety of programs
appeared successful, and both comprehensive and
less-comprehensive programs appeared to have been

More specifically, the findings of the illustrative PES
with regard to the requester’s questions were
summarized as follows.

1. The pattern of credible results showed no clear
preference between the two proposed programs. A
variety of past programs appeared successful, but
there was little information on the components that
were responsible for their apparent success. And
there was no convincing evidence that the most
comprehensive service packages were more effective
than the least comprehensive.

2. Implementation analyses suggested that there were
certain avoidable operational problems associated
with the proposed administrative structures. For
example, program administrators as well as
evaluators frequently mentioned complex
coordination arrangements as a significant obstacle to
program success.

3. Therefore, if the Congress wanted to initiate a
nationwide program, then the administratively
simpler model might have a greater chance of
success. However, we concluded that the evidence
was most

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                           The PES: Middle and Final Steps

Table 5.5: Example of Presenting PES Findingsa

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  This is one segment of a longer table. It illustrates an
intermediate summary of findings by offered services. The
table included verbal and graphic material. The “C7” and the
other code numbers in the second column refer to full
bibliographic data for each comparison in the teenage
pregnancy report from which we have taken the table.

Source: U.S. General Accounting Office, Teenage Pregnancy:
500,000 Births a Year but Few Tested Programs,
GAO/PEMD-86-16BR (Washington, D.C.: July 1986), p. 47.

consistent with initiating a large-scale demonstration
program that would systematically test the feasibility,
costs, and benefits of different approaches to
reducing teenage pregnancy.6

In this particular instance, the conclusions did not
clearly favor the legislative proposal that was
prescriptive (given the lack of strong evaluative
knowledge) and relied on existing services (given past
experience with complex coordination processes). In
addition, the smaller, more flexible proposal had to
take into account the need to develop information
about which strategies work with which teenagers.
Thus, no clear advantage adhered to the one
compared to the other. This is not always the case for
a PES and, in fact, did not occur in another example
of the method dealing with catastrophic health

 Two options were suggested as consistent with the analyses. (1) If
expansion of available services is wanted, then it would make
sense to target services to the teenagers who are at highest
risk—young and unmarried teenagers—to allow flexibility in the
type of services provided and to have a simple administrative
structure. (2) In an alternative to a program of expanded services,
the federal government could take the role of promoting innovation
and ensuring both sound comprehensive evaluations of the
innovations and dissemination of the programs (or their
components) that have been shown to work.

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insurance proposals.7 However, the importance of the
teenage pregnancy example is real in that it saved
taxpayer resources, since neither proposal had been
introduced in a form that was likely to succeed.

 See U.S. General Accounting Office, 1987f. In this report, we
looked at six legislative proposals for protecting Medicare enrollees
from the financial hardships that often accompany catastrophic
illness. Our review, and in-depth analysis of two of these six,
determined that while protection would increase, some gaps would
remain. We further identified issues requiring additional
consideration, such as coverage of prescription drugs. Our
conclusions played a significant role in both hearings and the
subsequent configuration of the act.

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Chapter 6

Variants of the PES

                          Several variants of the PES are possible. They are of
                          two types. The first variant derives from targeting the
                          PES: customer interest in special aspects of a
                          proposal. The second variant involves combining the
                          PES with sources of information other than prior
                          written evaluations. Using multiple methods would, of
                          course, notably expand the range of the PES. Further,
                          it is typical of designs for many of GAO’s important or
                          controversial jobs that we use several methods, so
                          that the limits of one are offset by the strengths of

                          The basic model of the PES we described in chapter 3
Targeted PES              is appropriate when relatively well articulated
                          proposals have been developed. However, the PES
                          can be helpful in other, more limited situations, as
                          when a problem is being defined or when costs are of
                          particular interest. In essence, aspects of the full PES
                          discussed earlier become the target of more limited
                          work. Table 6.1 summarizes some of the variants of
                          the PES.

Table 6.1: Targeted PES
and Related Critical      Target                         Critical issue
Issues                    Problem definition             Determining the fit between
                                                         the perceived problem and
                                                         legislative proposals
                          Problem characteristics        Assessing data quality and
                                                         narrowing or resolving
                                                         contradictory estimates
                          Relation of proposal to        Clarifying underlying
                          prevailing scientific models   assumptions
                          Assessing projected costs      Checking sensitivity of
                                                         projections against varying

The PES and               For many issues that come before a legislative body,
Problem Definition        some critical problem has been identified by the

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Variants of the PES

proposers of legislation, along with suggested
measures expected to resolve the problem. If the
problem is a major one, it is rare that only one piece
of legislation will be proposed. Even in such cases, as
already noted, every proposal has an implicit
alternative—namely, not to enact any legislation at
all. In any case, before a judgment can be made about
whether the proposed measure will resolve the
problem, it is important to be clear about exactly
what the problem is.

Proposed legislation designed to address a particular
problem is necessarily based on some definition or
understanding of the issue involved. For example,
two contending legislative proposals may both be
addressed to the issue of homeless persons, one
identifying the homeless as needy persons who have
no kin upon whom to depend and the other defining
homelessness as the lack of access to conventional
shelter. The first definition centers attention primarily
on the social isolation of potential clients, while the
second focuses on housing arrangements. It is likely
that the ameliorative actions that follow will be
different, as well. The first might emphasize a
program to reconcile estranged persons with their
relatives, while the second might imply a subsidized
housing program. Thus, the two definitions lead to
different proposals.

Especially critical in problem definition is the fit
between what is perceived to be the problem by those
who have pressed for attention to the issue and the
definition in the legislative proposals. In this
connection, the PES evaluator would ordinarily refer
to legislative proceedings, including committee
hearings and floor debates, journals, newspaper and
magazine editorials, and other sources in which
discussions of the problem may appear. The purpose
of this review of sources is to examine how the

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                   problem has been formulated and to state as clearly
                   as possible the range of politically acceptable

Problem            To design a public program properly and to project its
Characteristics:   costs reasonably well, good information is needed on
Density and        the density, distribution, and overall size of the
                   problem. For example, in providing financial support
Distribution       for emergency shelters for homeless persons, it would
                   make a significant difference if the total homeless
                   population is 2.5 million or 250,000 (both estimates
                   have been advanced). It would also make a difference
                   whether the problem is located primarily in central
                   cities or can be found in equal densities in smaller and
                   larger places.

                   An identified problem is often a complex mixture of
                   related conditions; for planning purposes, specific
                   information is needed about that complexity. In the
                   example of homelessness, the proportions of the
                   homeless suffering from chronic mental illness,
                   chronic alcoholism, or physical disabilities has to be
                   known in order to appropriately design the relevant
                   mixture of programs.

                   It is much easier to identify and define a problem than
                   to develop valid estimates of its density and
                   distribution. For example, only a small handful of
                   battered children may be enough to establish that a
                   problem of child abuse exists. However, to know how
                   great a problem is and where it is located
                   geographically and socially involves detailed
                   knowledge about the population of abused children
                   and its distribution throughout the political
                   jurisdiction in question. Such exact knowledge is
                   ordinarily much more difficult to obtain with the kind
                   of precision that may be needed.

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To collate and assess whatever information exists on
the issues in question, evaluators need to use what
they have learned from the literature (consisting of
government reports, published and unpublished
studies, and limited-distribution reports) and their
understanding of the designs and methods that lead to
conclusive results. Equal emphasis is given in the last
sentence to “collate” and “assess.” Unevaluated
information can often be as worthless as no
information at all.

For some issues, existing data sources may be of
sufficient quality to be used with confidence. For
example, an issue on which measurements are
routinely taken by either the Current Population
Survey or the decennial census is typically an issue
about which accurate and trustworthy knowledge
ordinarily may be obtained from those sources. Data
from some other statistical series, such as those
published by the Bureau of Labor Statistics, also fall
into the trustworthy category. But when we deal with
data produced by other sources, it is necessary to
examine with care how the data were collected.

A rule of thumb is that for any subject, existing data
sources provide contradictory estimates. But even
chaos can sometimes be reduced to some order.
Seemingly contradictory data on the same topic
collected by opposing stakeholders can be especially
useful for assessment purposes. For example, both
the Coalition Against Handguns and the National Rifle
Association have sponsored sample surveys of the
U.S. population concerning their approval or
disapproval of gun-control legislation. Although the
two reports issued by the coalition and the
association differed widely in their conclusions, the
one finding much popular support for more-stringent
gun-control measures and the other the opposite, a
close inspection of the data showed that many of the

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                        Variants of the PES

                        specific findings were nearly identical in the two
                        surveys. The findings upon which both surveys
                        substantially agreed can be regarded as having the
                        greater credibility.

Relating Proposal       Whether explicitly intended or not, legislative and
Models and              other proposals are based on some set of ideas or
Prevailing Scientific   models of how the problem in question may have
                        arisen and how it is currently sustained. For example,
Models                  one welfare reform alternative suggests extending to
                        all states the coverage of public welfare to intact
                        families with unemployed parents in order to reduce
                        the number of households headed by women. This
                        proposal may be based on a model that sees current
                        welfare policies as penalizing marriage, since benefits
                        to a woman and her children would stop upon

                        An alternative welfare reform proposal might suggest
                        that benefits be continued upon marriage but reduced
                        by some proportion to avoid subsidizing parasitic
                        marriages. Both proposals involve extending benefits
                        to intact families, one to support such families when
                        both parents are unemployed and the other without
                        regard to the employment status of a new parent.
                        Each proposal is based on different models of how
                        payments might affect marriages of households
                        headed by women. In the first case, the proposal is
                        based on the idea that women will avoid marriage to
                        unemployed men because they would lose their
                        benefits, and it ignores the effects that marriage to an
                        employed man would have. The second proposal is
                        concerned with the possibility that the continuation
                        of benefits after the marriage of a woman head of
                        household might render the woman susceptible to
                        marrying a man who was primarily interested in
                        sharing her benefits.

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Both proposals are based on models that stress the
role of economic incentives in marriage formation, a
topic that has received considerable attention in
microeconomic theory, econometric research, and
social psychology and sociology. An appropriate
tactic for the PES would be to review this literature,
seeking to establish two things: (1) the extent to
which experts agree and (2) the existence of
empirical evidence concerning the intended effects of
either proposal. A thorough review of the existing
literature accompanied by consultation with
subject-matter specialists and knowledgeable
practitioners could determine that one of the
proposals has more support than the other, that there
is as much evidence for one as for the other, or,
alternatively, that neither proposal has much positive
backing in research and experience.

An important opportunity is presented when a PES
finds that there are very few or no previous
evaluations that are relevant because the proposed
program is a notable departure from programs
evaluated in the past. A clear message can be sent to
decisionmakers that their proposals go far beyond
firm knowledge and are, hence, subject to a
more-than-ordinary risk of failure.1 This advice need
not be an admonition to stick to the programs of the
past. For example, the advice may be to fund
demonstration projects incorporating the new
proposals rather than to fund fully operational
programs. Pointing out areas on which existing
knowledge has nothing to say may be as important for
the avoidance of public policy failures as gathering a
rich harvest of firm knowledge.

  We would need to take into account that not acting carries its own
risks of failure. For example, while we may have little certainty
about effective AIDS prevention measures, not making the best
efforts we can also incurs risks.

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Assessing Projected   Legislative proposals are often accompanied by
Costs                 projected costs. In fact, all the bills that are reported
                      out of committee include a Congressional Budget
                      Office cost estimate. Although any projection can be
                      easily upset by subsequent actual experience, it is
                      usually possible to make a viable assessment
                      concerning whether projected costs are based upon
                      reasonable and likely assumptions. For example, the
                      projected cost of a proposed measure that would
                      subsidize flood insurance for structures built on flood
                      plains can be profoundly affected by assumptions
                      made about the number of structures that are to be
                      covered and the participation rate among potentially
                      covered households.

                      If the flood plains are defined as areas within a
                      100-year flood zone—where a major flood is expected
                      at least once every century—coverage will be greater
                      but flood incidence will be lower than if the limits of
                      the flood plain were defined as a 20-year flood plain.
                      If all the applicable property owners participated,
                      anticipated costs might be more than if the
                      participation rate were much lower. But there are also
                      other complications that affect cost. If only the
                      property owners who were close to the source of
                      floods signed up, then the subsidy costs might be
                      greater than if participation rates were more uniform
                      over the flood plain.

                      A PES can help assess cost projections by judging
                      whether the appropriate assumptions have been made
                      in their construction, as well as by proposing
                      alternative assumptions. Here the statistical analysis
                      tests how responsive the projections are to alterations
                      in the assumptions. It raises questions like how much
                      costs would be changed if participation rates were
                      changed by a given amount or if unit prices of
                      services were changed. Sensitivity analyses highlight
                      the assumptions concerning the costs that are the

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                     Variants of the PES

                     most critical to the overall cost estimate. Further, as
                     part of the PES analysis, estimates of the magnitude
                     and direction of the problems of under- or
                     overcosting that were identified could be applied to
                     existing information and synthesized into a
                     meaningful range.

                     The basic PES operational model uses prior
Variants Using       evaluations or research as the source of information.
Other Sources of     If, in reviewing this literature, tradeoffs should be
Information          made between timeliness and comprehensiveness,
                     strategies such as sampling and time-limited searches
                     could be adopted. There may be situations, however,
                     when available information must be supplemented
                     with some original data collection and when it may be
                     more efficient to tap into existing knowledge through
                     panels or expert judgments. Further, there may be
                     situations where the PES is combined with original
                     data collection and other audit work.

Combining the PES    The results of the PES may be supplemented with
With Some Original   some original data collection, such as examination of
Data Collection      agency records or surveys. That is, where existing
                     data are insufficient and where time and resources
                     permit, evaluators may want to use PES procedures
                     up to the point of matching evidence and key
                     assumptions. At this point, the PES could proceed on
                     dual tracks with some highly targeted new data being
                     collected while other, prior work is reviewed. Several
                     of the reports already mentioned, such as one on the
                     consequences of opening more combat support
                     positions and units to women, involved multiple
                     methods of data collection in answering a prospective
                     question. (U.S. General Accounting Office, 1988h)

                     For example, we were asked by the Congress to
                     determine what might be learned from state and local

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experience in addressing mandate burdens. A law
already in place since 1981 required the Congressional
Budget Office to estimate such costs for proposed
federal legislation. Similar requirements for reviewing
the costs of proposed state legislation exist in 42
states. New legislation proposed by the congressional
requesters would have required federal
reimbursement for additional costs. This approach
was already in use in 14 states that reimbursed local
governments for burdens imposed by new state laws.
(U.S. General Accounting Office, 1988n) The methods
for answering the prospective question included a
review of the literature, analysis of relevant bills, and
visits to 8 states selected by searching prior studies,
plus a telephone survey. Data from the 8 states were
supplemented by questionnaires for state officials,
state legislative leaders, and relevant interest groups.
Using evidence from these 14 states, we found that
estimating and reimbursing costs have had only a
limited effect on the burden of mandates, except in
some special circumstances.

When may such original data collection be
particularly valuable? One might expect that in areas
such as defense and tax policy, our unique access to
data is likely to mean we would have better
information than one could expect to find in the
published literature. In other areas, however, such as
certain aspects of health that require confidentiality in
dealing with patients’ records, physicians who are
also evaluators and researchers might have the
relative advantage and would find a richer data base
in published reports than we ourselves might be able
to collect. That is, combining the PES with other
forms of audit and evaluative work is consistent with
the multimethod approach we typically use. However,
evaluators planning a PES can also anticipate, to a
certain extent, where we may find a relatively rich
data base and where our unique authorization may

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                        Variants of the PES

                        suggest the need for new data collection to
                        supplement the PES.

Combining the PES       The evaluator supplementing other evidence with the
With Expert             views of experts must be aware of the requirements
Judgment                of systematic methods such as Delphi techniques.
                        Properly applied, these systematic methods yield
                        information that differs in some key ways from the
                        anecdotal evidence on which congressional testimony
                        is often based. First, the effects of “charisma” in
                        presenting testimony are ruled out. Second, since the
                        same questions are usually asked of many key
                        informants, it is possible to determine what opinion is
                        generally held. Third, the bases for opinions are
                        brought out and can be compared objectively with
                        available evidence. Fourth, the experts or key
                        informants can be selected primarily or solely by
                        considerations such as knowledgeability and
                        appropriate diversity.

                        We have used expert judgment and panels in a variety
                        of ways to answer prospective (and also
                        retrospective) questions. For example,

                    •   to assess major welfare reform proposals dealing with
                        case management, contracts between welfare
                        recipients and agencies, coordination of services, and
                        target populations, HRD contracted for two panels of
                        experts. One panel consisted of experts at the
                        national level and was convened by the National
                        Academy of Public Administration; the other panel
                        consisted of experts at the local level and was
                        convened by the Federation for Community Planning.
                        The findings of both panels were synthesized by GAO
                        and the numerous concerns, observations, and
                        recommendations were presented to the Congress as
                        the insights of expert panels. (U.S. General
                        Accounting Office, 1988b)

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•   to examine the probable effects of legislation that
    would change the conditions for legal immigration,
    we identified (in consultation with the customer) the
    issues and we brought together a panel of experts.
    The experts identified the highest-quality data
    relevant to these issues and presented their own
    conclusions. We then independently assessed the
    conclusions, relative to our own judgment of the
    quality of the evidence, in order to report the
    soundest available statement on probable effects.
    (Chelimsky, 1989)

    The use of expert judgment to supplement our
    prospective work requires (1) clarity in presentation
    when we are relying primarily on the opinions of
    others and (2) careful planning when the experts are a
    significant source but our own, independent judgment
    is needed. In the instance of proposed immigration
    legislation, the experts helped sharpen the issue,
    identified relevant empirical data, and examined
    points of consensus and dispute in the interpretation
    of the data. We then independently reviewed the
    available information and reached our own
    conclusions by the usual standards of audit and
    evaluation work. (Chelimsky, 1989)

    In another instance, GAO had a problem-definition
    assignment—examining the nature and extent of
    sweatshops in the United States and identifying the
    policy options that might help control the problem.2
    In this study, which was clearly entitled opinions on
    the extent of the problem and possible enforcement
    options, we reviewed the relevant literature on
    sweatshops, particularly with regard to their origin
    and efforts at control; developed a working definition
    (since the term is not defined in federal statutes or
    regulations) in agreement with the customer;

     See U.S. General Accounting Office, 1988j. This was not formally a
    PES but illustrates a multimethod approach to analyzing a problem
    and possible action.

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interviewed federal, state, and local officials,
researchers, and union and management experts;
surveyed state labor departments and agency
officials; investigated possible sweatshops in New
York and Los Angeles; and analyzed federal
inspection reports. While this required more effort
than might usually be available for a PES, it illustrates
that for certain prospective questions, GAO can
negotiate with the congressional customer the time to
undertake quite extensive involvement of experts, as
well as site visits, to supplement the literature.

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Appendix I

A Brief History of the PES and Some
Other Prospective Methods

             This appendix helps place the PES in relation to other
             methods. Traditionally, the basic concepts of
             evaluation have been used primarily in the
             assessment of policies and programs that are already
             in place. This ex post application has become so
             commonplace that it is the one most frequently
             associated with evaluation. Less frequently,
             evaluation methodology has been used to assess ex
             ante the potential success of policies that are under

             The conventional approaches to prospective
             evaluations have ranged widely from relatively
             freewheeling “demonstrations” to highly controlled
             field experiments. However, most proposed programs
             are put into operation—often nationwide—with little
             evaluative evidence attesting to their potential for
             success. (Some of the unevaluated programs that
             have been put in place have to do with recent drug
             laws, various regulatory programs targeting improved
             health, “deinstitutionalization,” “the strategic defense
             initiative,” “pilot cities,” “impact cities,” “model
             cities,” “operation push,” and “operation

             But even when small-scale pilot efforts of an
             experimental sort are implemented—and most
             evaluators would agree that highly controlled field
             experiments yield the most credible results—the
             experiments have many practical drawbacks.1 In
             particular, three serious limitations must be taken
             into account when they are considered for use as the

              Pilot and experimental studies can provide crucial intellectual
             capital on which synthesis draws. They are among the primary
             sources of information which the PES relies. That is, a PES benefits
             from having available a good fund of knowledge based on
             evaluations of other programs, research knowledge, and so on.
             Thus, the PES does not replace the new data collection forms of
             program evaluation. Pointing out the limitations of pilot and
             experimental studies should not be misconstrued as arguing against
             this valuable prospective method.

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A Brief History of the PES and Some
Other Prospective Methods

only application of evaluation methodology to the
assessment of prospective public policies. Consider,
for example, three randomized public policy
experiments: the five income-maintenance
experiments, the housing allowance experiments, and
the several experiments on demand pricing of
electricity. First, they were costly. On this ground
alone, it would not be likely that more than a small
handful of experiments could be set under way during
any decade. That is, only a minute proportion of the
public policies and programs that are in any current
policy space could possibly be assessed through field

Second, these field experiments were limited to the
consideration of only a narrow band of alternative
policies. Indeed, none of the income maintenance
experiments came close to testing the actual public
welfare policies that were considered by the Congress
and the executive branch in the years since their
completion. Policy space tends to be occupied by
more contenders than can easily be accommodated in
the design of the typical field experiment.2
Furthermore, with every new administration or
session of the Congress, the contending policies and
programs, as embodied in various versions of
proposed legislation, are never a static body and may
in fact be constantly changing.

Third, public policy experiments take a long time to
complete. Legislative proposals are often decided
within the space of months and, at most, a few years.
Clearly, field experiments that take 5 years to run and
another 3 to analyze can rarely speak directly to any
set of specific, proposed laws for the many years that
typically pass before results appear. To some degree,

This does not mean that the field experiments were irrelevant.
Almost all the proposed welfare reform measures involved
work-leisure tradeoff issues, a topic about which the five income
maintenance experiments have much to contribute.

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A Brief History of the PES and Some
Other Prospective Methods

these deficiencies are also characteristic of other
prospective efforts.

Pilot demonstrations that call for the collection of
original observations in the field may take almost as
long to carry through to completion as field
experiments. Even cross-sectional surveys take
significant periods of time. For example, a national
household sample survey ordinarily takes from 6
months to up to 2 years to complete (depending on
the complexity of sampling and analysis). In short,
although “demonstrations” and quasi-experimental
trials of prospective policies may take less time to
conduct than the classical field experiments, they still
may require more than several years to complete. In
addition, they share the other drawbacks outlined
above, being expensive and subject to increasing
irrelevance with changes in the policy space.

In sum, the traditional ways in which evaluators have
faced the problem of providing information to
decisionmakers on the potential for success of
policies and programs that may be under
consideration at any time are not useful to a
decisionmaking process that may take no longer than
a year or two from proposal to definitive action. If
evaluations are to contribute to decisions about
proposed new programs, the contribution should be
accomplished through procedures that are relatively
inexpensive, speak to each of the variety of proposals
under consideration, and provide timely results.

There is nothing especially new or startling about this
idea, and many evaluators have given the problem
some thought. A relevant example is an application of
evaluative techniques to proposed legislation that
advocated the use of national health screening for
identifying abused children. (Light, 1973) The
American Evaluation Association has identified

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A Brief History of the PES and Some
Other Prospective Methods

front-end analysis as a major focus of attention.
(“Evaluation . . . ,” 1982) Indeed, even the more
extended forms of evaluation, such as randomized
field experiments, could benefit from a PES
conducted at the point of design. And there have been
other efforts in recent years to come to grips with the
problems of timeliness that are inherent in such
front-end analysis. Many of the specific elements of
PES have been advocated by others. In particular,
evaluability assessment as advocated by Joseph
Wholey emphasizes the construction of underlying
models of proposed programs in order to assess
whether a program or policy can be evaluated for
outcome effectiveness. (Wholey, 1977) In addition,
many others stress the importance of the theoretical
underpinnings of prospective programs. (Chen and
Rossi, 1983; Wang and Walberg, 1983; Gottfredson,
1984; Finney and Moos, 1984; Weick, 1980)

The main strength of the prospective evaluation
synthesis is that because it draws upon existing
knowledge and research to assess the potential
success of a new proposal, it can be timely enough to
be used within the policy development process. That
is, the PES will not necessarily provide the best
possible information that could be obtained under
optimal conditions, but it can provide in a timely
manner the best possible information that is currently

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Appendix II

Data Quality Judgment Models

              The PES relies primarily on the results of past
              evaluations of previous or existing programs. That is,
              the results of a PES could be notably different if
              different rules were used for including a given study.
              Because the weighing of criteria used to judge the
              quality of prior studies is so critical to the results of a
              PES, this appendix discusses in some detail a point
              not elaborated upon in our paper on the evaluation
              synthesis: how criteria are aggregated in reaching a
              decision of whether to use (or how much emphasis to
              give) a specific study. There are at least four different
              ways to assess the quality of prior evaluation studies.
              Table II.1 summarizes the advantages and
              disadvantages of these four approaches.1

               We also note the special case of where quantitative estimates are
              required as part of a PES. In this instance, careful attention should
              be paid to the adequacy of our estimates of values that go into the
              PES analysis, including an examination of the quality of the data
              and methods for checking their validity. If data are not of truly high
              quality, provisions for boundary or sensitivity analyses should be
              made. Further, any time the functions we have to deal with are
              likely to be multiplicative rather than additive, the accuracy of
              values entered into the analysis is critical, particularly in going
              from local to national estimates. The PES could identify points at
              which data must be aggregated and could identify the vulnerability
              to multiplicative effects, where it is not possible as part of the PES
              to make these better estimates ourselves.

              Page 94              GAO/PEMD-10.1.10 Prospective Evaluation
                         Appendix II
                         Data Quality Judgment Models

Table II.1: Advantages
and Disadvantages of     Model                 Advantages               Disadvantages
Four Data Quality        One criterion         Maximum number One strong report
Judgment Models                                of prior reports   may be a better
                                               brought to bear    guide than 20
                                                                  weak ones
                                               Large number of
                                               reports permits    One criterion is
                                               tests of           unlikely to be
                                               interactions       adequate, and
                                                                  interactions of
                                               Analysis may be data of mixed
                                               quicker since      quality may be
                                               time for multiple  misleading
                                               quality screens is
                                               not taken
                         Equally weighted      If all criteria are in
                                                                   When several
                                               fact equally        criteria are
                                               important, this     relevant, one may
                                               model may best      have little to
                                               represent the       analyze if a
                                               quality of the priorthreshold for all is
                                               evaluations         set, but not
                                                                   setting a
                                               Permits direct test threshold may
                                               of whether taking permit a modest
                                               quality into        strength to offset
                                               account would       a serious flaw in a
                                               make a difference study
                                               in the findings
                                                                   Rare to find all
                                                                   criteria equally

                         Page 95            GAO/PEMD-10.1.10 Prospective Evaluation
Appendix II
Data Quality Judgment Models

Model                   Advantages          Disadvantages
Unequally weighted Better represents        A modest
                   relative                 strength in one
                   importance of            significant
                   different criteria       criterion can still
                                            offset a serious
                        Permits direct test flaw in another
                        of whether taking criterion if there
                        quality into        are two or more
                        account would       heavily weighted
                        make a difference criteria
                        in the findings
                                            Can be
                                            cumbersome to
                                            assign and
                                            compute weights
                                            for each criterion
                                            for each study, as
                                            well as to make
                                            ratings on each
                                            criterion on each
Threshold or fatal      Efficient in      Must be sure the
flaw                    focusing on most  fatal flaw is
                        crucial criteria  sufficiently
                                          serious to be a
                        Ensures that a    screen ruling out
                        study with high   studies that
                        scores on several otherwise are
                        relatively minor  potentially useful
                        criteria but a
                        Ensures that a
                        study with high
                        scores on several
                        relatively fatal
                        weakness in one
                        or more crucial
                        criteria is not

Page 96              GAO/PEMD-10.1.10 Prospective Evaluation
                   Appendix II
                   Data Quality Judgment Models

                   In this method, the set of prior research and
One Criterion      evaluation studies on the general topic is
Only               developed—say, on food-stamp participation, military
                   base closings, the effectiveness of federal programs
                   aimed at disseminating knowledge, or the quality of
                   executive and managerial personnel. The set is
                   examined against a single criterion.

                   For example, a decision might be made that only one
                   criterion such as measure validity should be really
                   important for the job. This might be true if we are
                   asked to assess the probable cost of a certain type of
                   child care. Prior evaluations of child care that did not
                   have information on costs that we considered
                   complete and properly measured would be rejected.
                   Those with valid cost information would be retained.

                   Except for the one selected criterion, other aspects of
                   the quality of the relevant reports are not assessed in
                   this method of synthesis. Rather, “strength through
                   numbers” is the intention, with the notion that the
                   largest possible set of prior studies that meet the
                   selected criterion will offer the soundest guide to
                   answering the question. In a variant of this method,
                   the information in the entire set of reports can be
                   judged on the single criterion. The extent to which the
                   answer to the evaluation question would differ when
                   higher-quality and lower-quality studies (as judged by
                   the single criterion) are used can be determined.

                   Among advantages of this approach are that it draws
                   on a large possible body of data. A prime
                   disadvantage is that it is quite rare that only one
                   criterion of study quality would be important. The
                   evaluative question, as noted, would have to be quite
                   limited in scope.

                   In this approach, a set of criteria for selecting the
Equally Weighted   prior research to be synthesized is developed.
                   Page 97          GAO/PEMD-10.1.10 Prospective Evaluation
                    Appendix II
                    Data Quality Judgment Models

                    Typically, the set includes relevance, recency, context
                    similarity, and a variety of indicators of technical
                    adequacy including those appropriate to
                    measurement, design, analysis, and reporting.

                    Each of these criteria is given equal weight in
                    deciding whether or not to include the report, article,
                    or book in the set of material to be synthesized. That
                    is, a high score on relevance might offset a lower
                    score on technical adequacy when a “total” quality
                    score is derived and the cut-off established for
                    whether a study is included. Or, alternatively, a
                    threshold score in all criteria may be required for the
                    report to be used.

                    GAO has many examples of this approach, including
                    the criteria described in the reviews of the effect of
                    illegal aliens on legal workers and the effect of the
                    drinking-age laws on highway safety. (U.S. General
                    Accounting Office, 1986a, 1987b) An advantage to this
                    approach is that the effects of various aspects of
                    quality can be tested empirically. A disadvantage is
                    that particularly if a threshold is set for all criteria,
                    almost no studies may pass the quality screen.

                    In this approach, the criteria receive different
Unequally           weights. For example, technical quality may be seen
Weighted Criteria   as more important than recency in deciding whether
                    or not to include the study. Among the
                    technical-quality criteria, for some questions the
                    extent to which the design permits strong inference
                    about causality may be seen as much more important
                    than, say, the extent to which documentation of
                    measurement reliability exists. The weights are not
                    arbitrary but are guided by the theory underlying the
                    methods. Again, there are examples of this approach.
                    (U.S. General Accounting Office, 1984a)

                    Page 98          GAO/PEMD-10.1.10 Prospective Evaluation
               Appendix II
               Data Quality Judgment Models

               This approach has the advantage of better
               representing the importance of different criteria. It is
               still possible, however, that modest strength on
               several relatively less important criteria can offset a
               serious flaw on a significant criterion, if scores on
               each criterion are aggregated.

               In some situations, a report that does not pass muster
Threshold or   on a specific criterion is not considered at all, and
Fatal Flaw     other criteria come into play only after the “fatal flaw”
               test has been passed. For example, in a synthesis of
               studies on the homeless mentally ill, reports that did
               not attempt to estimate the size of the local
               population of the homeless were excluded from
               consideration. Further, within the useful studies, a
               fatal flaws criterion (sampling the range of settings)
               set a cap on rated quality. That is, among the studies
               that estimate population size, the quality of the report
               was judged against seven other criteria and the
               direction and extent of bias were judged. The
               technical-quality rating was the profile of whether the
               errors were likely to lead to an overestimate bias or
               an underestimate and the size of the bias. (U.S.
               General Accounting Office, 1988i, 1988d)

               This model is the most efficient way to ensure quality.
               The fatal flaw must be carefully examined, however,
               to be sure that no offsetting features are possible,
               since potentially informative studies that fail on only
               one criterion may be excluded from the review set.

               Table II.2 provides a detailed example of the criteria
               used and how they were applied with regard to the
               number of homeless mentally ill persons.

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                             Appendix II
                             Data Quality Judgment Models

Table II.2: Example of a Fatal Flaws Analysis
What we did              How we did it
Screening the studies   In defining our universe of studies for the evaluation synthesis,
                        we purposefully kept our inclusion criteria broad. We included
                        any study, regardless of methodological quality, that attempted
                        to estimate the size of the homeless or homeless mentally ill
                        population. We did, however, have some minimum inclusion
                        criteria. Of our universe of 83 studies, 27 were selected as
                        useful. Specifically, we included a study in our universe if it met
                        each of the following three criteria:

                        1. The study was in written form. Telephone conversations,
                        speeches, or conference proceedings without a written product
                        were not included.

                        2. The study provided a count or estimate (by whatever
                        method) of the homeless or homeless mentally ill persons or
                        assessed trends in a designated geographic area. This would
                        exclude case studies of individuals or studies describing
                        service needs without a count or estimate.

                        3. The method used to make the estimate of the number of
                        homeless or homeless mentally ill was sufficiently described to
                        permit us to evaluate its merits (or shortcomings). By
                        “sufficiently described,” we mean the study provided some
                        information on

                        — the data used to make the estimate (for example, expert
                        judgments or actual counts of persons in shelters);
                        — how those data were collected (for example, shelter-
                        providers were interviewed over the telephone, streets were
                        canvassed by car, and so on);
                        — how the estimate of the size of the homeless or homeless
                        mentally ill population was actually computed (for example, how
                        shelter and street counts were aggregated). That is, there was
                        some kind of link between the data collected and the final
                        population estimate.

                             Page 100           GAO/PEMD-10.1.10 Prospective Evaluation
                             Appendix II
                             Data Quality Judgment Models

What we did             How we did it
Assessing the studies   Next we rated the 27 relevant studies on two dimensions:
                        technical quality and soundness (that is, the extent to which the
                        chosen method would produce an underestimate or
                        overestimate of the size of the homeless population). We
                        discovered that many of the studies involved multiple methods
                        for counting the homeless, reflecting the various settings
                        (shelters, streets, institutions) in which the homeless and
                        chronically mentally ill can be found. We considered each of
                        these “nested studies” for how well it met survey methodology
                        standards for soundness. Criteria for methodological
                        soundness encompassed such issues as adequacy of universe
                        definition, coverage of sampling frame, implementation
                        procedures, and soundness of data analysis. We developed
                        and applied a coding form to extract data relevant to these
                        criteria. Finally, two staff members rated the full studies on
                        criteria related to their overall sampling, measurement,
                        implementation, and population estimation procedures.
Sampling design         Did the design cover the range of settings where homeless
                        persons were likely to be found (shelters, streets, other public
                        places, institutions)?

                        Was the sample of shelters and institutions representative in
                        terms of the area’s shelter size (that is, number of beds) and
                        type (public or private)?

                        Did the sample of streets and other public places (such as
                        census blocks) adequately cover the locations where the
                        homeless are known to congregate?

                        Did the sampling design account for seasonal variation in

                        Was the unit of analysis (such as municipality) clearly defined?
Measurement             Was the estimate of the number of homeless based on an
                        actual count rather than expert judgment?

                        Was a respondent’s homeless status determined on the basis of
                        screening questions?

                             Page 101          GAO/PEMD-10.1.10 Prospective Evaluation
                             Appendix II
                             Data Quality Judgment Models

What we did             How we did it
Implementation          Were survey procedures explicitly stated in the report?

                        Were interviewers trained to engage with and administer
                        interviews to homeless persons?

                        Were instruments pretested?

                        If a street survey was conducted, were canvassing procedures
                        consistently applied in areas searched? Were areas
                        enumerated before the actual street survey was conducted?

                        If a shelter-and-institutions survey was conducted, was the
                        count based upon administrative records rather than subjective
                        estimates? Were procedures developed to ensure an
                        unduplicated count of the homeless within shelters and
Deriving the population Was the estimate of the number of homeless based upon a
estimate                probability sample of areas (such as a national estimate based
                        upon a probability sample of cities)?

                        Were adjustments from the sample made to estimate the
                        population (for example, was the application of a
                        shelter-to-street ratio obtained from previous studies)
                        appropriate and justified?
Fatal flaws analysis    In applying these criteria, we gave a higher priority to the
                        sampling dimension. That is, if a study did not adequately
                        sample the range of settings where homeless persons stay,
                        there was a limit on how high the study could be rated, no
                        matter how strong the measurement, implementation, and
                        estimation procedures. To illustrate, a study that had a strong
                        sampling design (for example, surveyed many settings) but
                        used simple estimation procedures was rated higher than a
                        study that had a weak sampling design (for example, surveyed
                        only shelters) and used sophisticated statistical adjustments to
                        account for the fact that streets or institutions were not
                        surveyed. Accounting for sampling bias by using statistical
                        adjustments—in some cases the only option available—is
                        based on assumptions about the size of the homeless
                        population in the settings not included in the survey, not an
                        actual count. Applying the criteria in this manner, we rated each
                        study’s technical quality very high, high, moderate, low, or very
                             Page 102          GAO/PEMD-10.1.10 Prospective Evaluation
                   Appendix II
                   Data Quality Judgment Models

What we did   How we did it
              Our second rating helped us distinguish where on the
              technical-quality scale (very high to very low) studies could be
              considered sound enough to provide reliable estimates. The
              soundness of studies was determined by rating each study on
              the extent to which its methodology would produce, in our
              judgment, an underestimate or overestimate of the number of
              homeless persons. For example, a study that employed a
              design that relied solely on the estimates of service providers
              would be rated as having the potential for overestimating the
              size of the homeless population. Each study was assigned a
              rating on a 7-point scale that ranged from –3 (serious
              underestimate) to +3 (serious overestimate). A written
              justification was given for each bias rating.

              To determine a cutoff point for the methodological soundness,
              we selected studies that received a bias rating of –1, 0, or +1.
              In addition to providing a cutoff point, this second rating
              indicates the direction and likely magnitude of the bias in each

              We used the information from these ratings to get an overview
              of the current approaches and research designs that are being
              used to count homeless and homeless chronically mentally ill
              persons. This information formed the basis for a closer
              examination of the patterns of strengths and weaknesses that
              were evident in the various studies and was applied in
              developing our alternative approaches.

                   Page 103          GAO/PEMD-10.1.10 Prospective Evaluation
Appendix III

A Project Evaluation Profile

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Appendix III
A Project Evaluation Profile

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Appendix III
A Project Evaluation Profile

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A Project Evaluation Profile

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A Project Evaluation Profile

Page 108          GAO/PEMD-10.1.10 Prospective Evaluation

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Page 114       GAO/PEMD-10.1.10 Prospective Evaluation
Papers in This Series

              This is a flexible series continually being added to and
              updated. The interested reader should inquire about
              the possibility of additional papers in the series.

              The Evaluation Synthesis. Transfer paper 10.1.2,
              formerly methods paper I.

              Content Analysis: A Methodology for Structuring and
              Analyzing Written Material. Transfer paper 10.1.3,
              formerly methodology transfer paper 3.

              Designing Evaluations. Transfer paper 10.1.4,
              formerly methodology transfer paper 4.

              Using Structured Interviewing Techniques. Transfer
              paper 10.1.5, formerly methodology transfer paper 5.

              Using Statistical Sampling. Transfer paper 10.1.6,
              formerly methodology transfer paper 6.

              Developing and Using Questionnaires. Transfer paper
              10.1.7, formerly methodology transfer paper 7.

              Case Study Evaluations. Transfer paper 10.1.9,
              formerly methodology transfer paper 9.

              Prospective Evaluation Methods: The Prospective
              Evaluation Synthesis. Transfer paper 10.1.10, formerly
              methodology transfer paper 10.

(973317)      Page 115        GAO/PEMD-10.1.10 Prospective Evaluation
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