Impact Evaluation: The Experiences of Official Agencies

Edited by: Howard White

January 2008
Volume 39 Number 1

Aid effectiveness has long been disputed, after decades of inconclusive macroeconomic analysis. Now there is a growing body of evidence from detailed, field level, microeconomic impact evaluations.

The articles in this IDS Bulletin show how the design of these studies increasingly address the various sources of bias for which previous projects were criticised. These later evaluations provide a firm basis on which to draw conclusions on aid effectiveness. Generalisations – bearing in mind specific contexts in which interventions have or have not worked – will come from further evaluations. This volume presents examples of these studies from a number of agencies: AFD, ADB, IDB, JBIC, the Netherlands Ministry for Foreign Affairs, USAID and the World Bank.

Challenges – such as enlarging study scale and technical skill, and resistance to new techniques – remain. While the situation is changing, deliberate action is required, specifically greater understanding of the scope and limitations of quantitative impact evaluation. Greater use of well-designed, theory-based, rigorous impact evaluations will enhance the likelihood of achieving international poverty reduction targets.

Impact evaluation design should ensure policy relevance and be able to answer not only what works but why, or why not. Qualitative fieldwork can lead to further quantitative analysis, resulting in clear and focused policy conclusions. While impact evaluations can be perceived as more expensive, within tight budgets the money must be best spent to ensure most effective learning and accountability. Local stakeholder involvement is another ingredient for the desired aim of policy impact.