Program Evaluation and Impact Assessment

Program evaluation is the systematic collection and interpretation of information about a health promotion program to judge how well it was delivered and what effects it produced. It distinguishes process evaluation, which examines whether the program was implemented as planned and reached its intended audience, from outcome and impact evaluation, which assesses changes in behaviour, health, and other targeted outcomes.

Definition

Program evaluation is the systematic assessment of a program's design, implementation, and outcomes using defined criteria and evidence; impact assessment is the component that estimates the changes in behaviour, health, or other outcomes attributable to the program.

Scope

The topic covers the purposes and main types of evaluation, the difference between process and outcome or impact assessment, evaluation frameworks used in health promotion, and the methodological challenges of attributing change to a program. It is a reference-educational overview of how programs are evaluated, not a protocol for evaluating a specific program.

Core questions

• What is the difference between process, outcome, and impact evaluation?
• How can changes in outcomes be attributed to a program rather than to other influences?
• What dimensions matter when judging a program's real-world public health impact?
• How are reach and sustainability assessed alongside effectiveness?

Key concepts

• Process versus outcome and impact evaluation
• Reach, effectiveness, adoption, implementation, maintenance (RE-AIM)
• Attribution and counterfactual comparison
• Formative and summative evaluation
• Sustainability assessment
• Mixed-methods evaluation

Key theories

RE-AIM framework

An evaluation framework assessing Reach, Effectiveness, Adoption, Implementation, and Maintenance, designed to capture a program's real-world public health impact beyond efficacy alone.

Mechanisms

Evaluation matches its questions to its methods. Process evaluation documents what was actually delivered, to whom, and with what fidelity and reach, which helps interpret whether a program failed in theory or in execution. Outcome and impact evaluation estimate the changes in behaviour and health that followed, ideally against a comparison condition so that change can be attributed to the program rather than to secular trends or other influences. Frameworks such as RE-AIM broaden the lens from effectiveness alone to reach, adoption, implementation, and maintenance, recognising that population impact depends on how many people a program reaches and whether its effects are sustained. Mixed-methods designs combine quantitative outcome measures with qualitative insight into how and why effects occurred.

Clinical relevance

Evaluation evidence determines which preventive and educational programs are judged worth continuing or scaling, and understanding it supports the critical reading of program reports. The topic describes how programs are assessed; it characterises evidence generation and is not a basis for individual clinical decisions.

Evidence & guidelines

The RE-AIM framework (Glasgow et al., 1999) is a widely used reference for evaluating real-world public health impact, and Green and Kreuter's planning text integrates evaluation into the PRECEDE-PROCEED model. Reviews of community intervention trials (Sorensen et al., 1998) discuss attribution challenges, work on sustainability (Shediac-Rizkallah & Bone, 1998) addresses maintenance, and Palinkas et al. (2019) review mixed-methods evaluation approaches.

History

Evaluation became central to health promotion as funders and practitioners sought accountability for program investments. Planning frameworks such as PRECEDE-PROCEED built evaluation into program design from the outset, and the introduction of RE-AIM in 1999 shifted attention from efficacy in controlled settings toward reach and impact in real-world conditions. Later work broadened evaluation to include sustainability and mixed-methods approaches that combine measurement of outcomes with understanding of process.

Debates

Attribution and the right comparison

Establishing that a program, rather than concurrent influences, caused observed change requires an appropriate counterfactual, which is difficult in community settings where randomisation is often impractical; the choice of comparison remains a central evaluation challenge.

Key figures

• Russell E. Glasgow
• Lawrence W. Green
• Marshall W. Kreuter
• Glorian Sorensen
• Lawrence A. Palinkas

Seminal works

• glasgow-1999
• sorensen-1998

Frequently asked questions

What is the difference between process and outcome evaluation?

Process evaluation examines whether a program was delivered as planned and reached its intended audience, while outcome and impact evaluation assess the changes in behaviour, health, or other targeted outcomes that followed.

Why is attribution difficult in program evaluation?

Observed changes may be due to the program or to other influences such as secular trends; without an appropriate comparison or counterfactual, it is hard to conclude that the program itself caused the change.