Background:This article describes eight flaws that occur in impact evaluations.Method:The eight flaws are grouped into four categories on how they affect impact estimates: statistical imprecision; biases; failure of impact estimates to measure effects of the planned treatment; and flaws that...

Background:Impact evaluations draw their data from two sources, namely, surveys conducted for the evaluation or administrative data collected for other purposes. Both types of data have been used in impact evaluations of social programs.Objective:This study analyzes the causes of differences in...