An impact evaluation is a systematic assessment that seeks to determine the changes or “impacts” caused by a specific intervention, such as a project, program or policy.
Unlike routine monitoring, which tracks outputs or activities, impact evaluation aims to establish a causal link between the intervention and its observed outcomes: the positive or negative, intended or unintended, short- and long-term effects on individuals, communities, or systems.
Purpose and Meaning of Impact Evaluation #
The main purpose of an impact evaluation is to answer key questions about effectiveness and causality: Did the intervention produce the intended results? Were those results a direct consequence of the program or caused by other external factors?
When and Why Conduct an Impact Evaluation #
An impact evaluation should be carried out when there is a clear decision to be informed, for example, whether to expand a successful pilot, justify funding, or compare alternative interventions. Timing also matters: if done too early, impacts may not have had time to materialize; too late, the evaluation may miss the critical window for informing decisions.
How Impact Evaluation Works #
- Define Key Evaluation Questions (KEQs)
- Use a Theory of Change
- Establish a Counterfactual.
- Collect Data and Analyze
- Synthesize Findings and Draw Conclusions
Why Impact Evaluation Matters #
Impact evaluation is a core part of monitoring and evaluation (M&E) because it moves beyond tracking inputs and activities to uncover real change. It provides credible, evidence-based answers to what works (or doesn’t), helping policymakers and implementers make informed decisions, optimize resource allocation, and improve program design.
By offering clear, transparent knowledge about the effects of interventions, impact evaluation supports learning, accountability, and smart development practice, making it an indispensable tool for anyone concerned with meaningful, measurable change.
List of recommended resources #
For a broad overview #
This video by the World Bank provides an introduction to the concept of impact evaluation and discusses how impact evaluation helps in determining how effective a program has been.
Understanding impact evaluation
This article by What Works Growth gives a broad understanding of impact evaluation. The article discusses why impact evaluation is important, the different types of evaluation, as well as its different methodologies.
For in-depth understanding #
Demystifying impact evaluation: an impact evaluation framework
This paper by Janet Michel and Kimon Schneider discusses the importance of impact evaluation in the current global landscape and proposes an impact evaluation framework with seven central tenets namely; Theory of change (TOC) or program theory, Stakeholder engagement including beneficiaries, Use of mixed method indicators, Baseline of outcome of interest, Midline assessment of outcome of interest, Endline assessment of outcome of interest and Validation/Co-creation.
This guide by INTRAC gives a comprehensive understanding of impact evaluation. The guide discusses the meaning of impact evaluation, when to use it and its different approaches along with its challenges.
Case study #
Impact Evaluation of “Invest in Pomerania” (2011-2020)
This report by the World Bank assesses the impact, that is conducts an impact evaluation, of Invest in Pomerania (IiP) on Pomerania’s economic performance in the period from 2011 to 2021. Upon reaching its ten-year anniversary, IiP seeks to better understand its contributions to attracting FDI and to the region’s economic development objectives.
Integrating Value for Money and Impact Evaluations: Issues, Institutions, and Opportunities
This mixed methods study by Elizabeth D. Brown and Jeffery C. Tanner probes into the issue of why fewer than one in five impact evaluations integrates a value-for-money analysis of the development intervention being evaluated.
References #
Impact Evaluation: What It Is and How It Strengthens Social Programs
Understanding Impact Evaluation: Definition, Benefits, and Best Practices
