Arguably the most aggressive affirmative action program ever implemented in the United States was a series of court-ordered racial hiring quotas imposed on municipal police departments.My best estimate of the effect of court-ordered affirmative action on workforce composition is a 14 percentage point gain in the fraction African American among newly hired officers.Evidence on police performance is mixed.Despite substantial black-white test score differences on police department entrance examinations, city crime rates appear unaffected by litigation.However, litigation lowers slightly both arrests per crime and the fraction black among serious arrestees.

Arguably the most aggressive affirmative action program ever implemented in the United States was a series of court-ordered racial hiring quotas imposed on municipal police departments. My best estimate of the effect of court-ordered affirmative action on work-force composition is a 14-percentage-point gain in the fraction African American among newly hired officers. Evidence on police performance is mixed. Despite substantial black-white test score differences on police department entrance examinations, city crime rates appear unaffected by litigation. However, litigation lowers slightly both arrests per crime and the fraction black among serious arrestees.

Using Electoral Cycles in Police Hiring to Estimate the Effect of Police on Crime: Comment by Justin McCrary. Published in volume 92, issue 4, pages 1236-1243 of American Economic Review, September 2002

This paper uses age-at-school-entry policies to identify the effect of female education on fertility and infant health. We focus on sharp contrasts in schooling, fertility, and infant health between women born just before and after the school entry date. School entry policies affect female education and the quality of a woman's mate and have generally small, but possibly heterogeneous, effects on fertility and infant health. We argue that school entry policies manipulate primarily the education of young women at risk of dropping out of school.

In the single-IV model, researchers commonly rely on t-ratio-based inference, even though the literature has quantified its potentially severe large-sample distortions. Building on Stock and Yogo (2005), we introduce the tF critical value function, leading to a standard error adjustment that is a smooth function of the first-stage F-statistic. For one-quarter of specifications in 61 AER papers, corrected standard errors are at least 49 and 136 percent larger than conventional 2SLS standard errors at the 5 percent and 1 percent significance levels, respectively. tF confidence intervals have shorter expected length than those of Anderson and Rubin (1949), whenever both are bounded.