Despite the billions of dollars spent on development assistance each year,
there is still very little known about the actual impact of projects on the
poor. There is broad evidence on the benefits of economic growth, investments
in human capital, and the provision of safety nets for the poor. But
for a specific program or project in a given country, is the intervention
producing the intended benefits and what was the overall impact on the
population? Could the program or project be better designed to achieve
the intended outcomes? Are resources being spent efficiently? These are
the types of questions that can only be answered through an impact evaluation,
an approach that measures the outcomes of a program intervention
in isolation of other possible factors.
Many governments, institutions, and project managers are reluctant to
carry out impact evaluations because they are deemed to be expensive,
time consuming, and technically complex, and because the findings can be
politically sensitive, particularly if they are negative. Many evaluations
have also been criticized because the results come too late, do not answer
the right questions, or were not carried out with sufficient analytical rigor.
A further constraint is often the limited availability and quality of data.