What is impact evaluation?

Impact evaluation is the systematic identification of the effects positive or negative, intended or not on individual households, institutions, and the environment caused by a given development activity such as a program or project. It is a type of evaluation which has received increasing attention in recent years. It is an important component of the armory of evaluation tools and approaches, albeit only one among a number. The purpose of this note is to provide an overview of impact evaluation, particularly of the more rigorous methods of impact evaluation. Lastly, its relevance to the work of the Independent Evaluation Group (IEG) is considered, and IEG ’s planned workplan in this area is then presented.

Role of IEG
IEG is an independent unit within the World Bank, and it reports directly to the Bank's Board of Executive Directors. IEG assesses what works, and what does not; how a borrower plans to run and maintain a project; and the lasting contribution of the Bank to a country's overall development. The goals of evaluation are to learn from experience, to provide an objective basis for assessing the results of the Bank's work, and to provide accountability in the achievement of its objectives. It also improves Bank work by identifying and disseminating the lessons learned from experience and by framing recommendations drawn from evaluation findings.

The World Bank’s operational staff conducts separate, self-evaluations of the Bank’s projects as soon as the project is completed; currently, about 270 new projects are completed each year. These self-evaluations are then assessed independently by IEG staff, using a rapid review approach based on standardized criteria.1 IEG ’s evaluation approach is termed objectives-based evaluation, focusing on whether a project’s actual outcomes are likely to achieve its stated objectives.

The specific criteria include:

• The relevance of the project’s objectives in relation to country needs and
institutional priorities;

• Its efficacy ― the extent to which its development objectives have been (or are
expected to be) achieved;

• Its efficiency ― the extent to which its objectives have been (or are expected to be)
achieved without using more resources than necessary;

• The sustainability of the project ― the likelihood that its estimated net benefits will
be maintained or exceeded over the life of the project;

• The institutional development impact ― the extent to which the project improves
the ability of a country to make better use of its resources; and

• The performance of the Bank and the borrower, focusing on how good a job each
partner has done at each stage of the project cycle.


More: IEG and Impact Evaluation -- A Discussion Note