Impact measurement is probably the most challenging task when designing and implementing a specific project or policy. Regardless of the nature of the agent carrying out the program, it is critical to address its potential effect on the target population.
The following video by the World Bank explains the general process -and a widely accepted methodology- for conducting impact evaluation:
However, it is not always feasible to measure impact using the above-mentioned methodology (i.e., for programs that are already in place). Therefore, designing a framework for impact evaluation beforehand should be a priority for governments, enterprises and non-profit organizations.