Social experiments are powerful sources of information about the effectiveness of interventions. In practice, initial randomization plans are almost always compromised. Multiple hypotheses are frequently tested. "Significant" effects are often reported with p-values that do not account for...

We study whether the combined significant reduction in the pupil-teacher ratio and increase in parental education observed in Italy between the end of World War II and the end of the 1980s have had a significant impact on the educational attainment and the labor market returns of a...