Impact Evaluation

What is impact evaluation?

The World Bank is committed to monitoring and evaluating the impact of its projects. Impact evaluation is a policy tool that helps discern the causal impact of a project or a policy initiative. Impact evaluation techniques compare the impact on the beneficiaries of a certain policy intervention or project with a counterfactual group that has not been exposed to the same intervention or project. The results from impact evaluations can help inform policy makers on where to allocate scarce resources and can also provide evidence on whether current policies are working or not. The economics of education cluster collaborates closely with the Development Economics Research group, the Human Development Chief Economists office and with country task teams to help project teams design and integrate impact evaluation components in education projects.

Conceptually, impact evaluation seeks to estimate the effect of a given intervention on a critical indicator (e.g., educational enrollment, standardized tests, etc) by comparing with and without the intervention on the same unit of observation. Of course observing the same individual with and without the program creates a fundamental problem given that we will never observe the same individual in two different states at the same time. Therefore, impact evaluation tries to asses the impact of programs trought techniques such as randomization of benefits, regression discontinuity analysis, differences in differences and propensity and matching estimators, among others.

Why is impact evaluation important?

Under limited budgets and scarce resources, public policy requires evidence of what works, and what does not. A rigorous impact evaluation can show if things work, and why they work. Effective evaluation will inform policy makers and permit improvements in policies and program implementation. Evaluation can inform program design (for example eligibility and types of benefits) and can improve operations and efficiency. Additionally, the information generated by impact evaluation may be useful for program sustainability and can be a valuable asset in the negotiation of budgets and in the provision of reliable information to inform public opinion. The lack of reliable information on the effects of many education projects is an area with important information gaps and merits the highest priority for future research.

The World Bank's Chief Economist has initiated a program to coordinate impact evaluations for projects and programs supported by World Bank lendings. Supported by the Human Development Network Chief Economist unit, the economics of education group works in close collaboration with the Development Economics unit on developing and designing impact evaluations for education projects. The World Bank Impact Evaluation website provides an up-to-date and comprehensive collection of materials on this topic including methods & techniques, key reading and selected evaluations on impact evaluation.