How do policymakers update their beliefs?

Abstract

We present results from experiments run in collaboration with the World Bank and Inter-American Development Bank on how policymakers, policy practitioners, and researchers update their beliefs in response to results from academic studies. Initially, policymakers both believe development programs will have more positive results and are more certain about it than policy practitioners and researchers, despite reporting less familiarity with the programs. When participants are presented with the results of impact evaluations, we find evidence they update more on good news and are relatively insensitive to confidence intervals. We do not observe significant differences in biases between groups, and these biases cannot fully explain differences in beliefs.