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...

"It is well known that children reared in non-intact families on average have less favorable educational outcomes than children reared in two-parent families. Evidence from the United States and Sweden indicates that living in a non-intact family is correlated with lower educational attainment....

Perhaps it does. We propose a model in which workers with little education or in the tails of the age distribution the inexperienced and the old have more chance of job failure (mismatch). Recruits' average education should then increase and the standard deviation of starting age decrease when...

"When studying income differences and income distribution, the self-employed are often excluded from the population studied. There are several good reasons for this, for example that incomes from self-employment are not reported to the same extent as incomes from being an employee. On the other...