In-group Favoritism and Peer Effects in Wrongful Acquittals: NBA Referees as Judges (with Naci Mocan)

NBER Working Paper No. 29860

IZA Working Paper No. 15195

Media: Boston Globe

We provide the first analysis of racial in-group bias in Type-I and Type-II errors. Using player-referee matched data from NBA games we show that there is no overall racial bias or in-group bias in foul calls made by referees. Similarly, there is no racial bias or in-group bias in Type-I errors (incorrect foul calls). On the other hand, there is significant in-group favoritism in Type-II errors. These are wrongful acquittals where the referee did not blow the whistle although a foul was committed. We also analyze peer effects and find that black referees’ proclivity to make Type-II errors in favor of black players exists as long black referees have at least one black peer referee on the court, and that the bias disappears only if black referees have two white peers. In case of white referees, in-group favoritism in Type-II errors emerges if white referees have two black peers with them on the court. We provide evidence showing that the results are not attributable to skill differences between referees. We also show that a higher Type-I error rate during the season lowers referees’ probability to be selected to officiate a game in the playoffs, whereas variations in the rate of Type-II errors have no impact on the likelihood of a playoff assignment. These results indicate that in-group favoritism takes place in a domain which is not costly (making Type-II errors), and that bias is eliminated when it is costly to the decisionmaker.


Saving Daylight, Losing Lives: The Impact of Daylight Saving Time on Deaths from Suicide and Substance Abuse

Forthcoming at Health Economics

This paper estimates the impact of Daylight Saving Time (DST) on deaths of despair (DoD) in the United States. Using Multiple Cause-of-Death Mortality Data from the National Vital Statistics System of the National Center for Health Statistics from 1979-1988, the effect is identified in two ways: a regression discontinuity design (RDD) that exploits discrete time changes in the Spring and Fall; and a fixed effects model (FE) that is identified with a policy change and a switching mechanism that introduces random variation to DST's start and end dates. This is one of the first attempts to estimate the impact of DST on DoD and is the first to use either identification strategy. The results from both methods suggest that the sleep disruptions during the Spring transition cause suicide rates to rise by 6.25 percent and all DoD to increase by 6.59 percent. There is no evidence for any change in suicide or all DoD during the Fall transition. The contrasting results from Spring to Fall suggest the entire effect can be attributed to disruptions in sleep patterns rather than changes in ambient light exposure.

The Effect of Minimum Wages on Time Allocation: Estimates Using Contiguous Counties

This paper estimates the impact of increases in the minimum wage on school enrollment, labor force participation, and idleness for people aged 16-19. Using the American Community Survey (ACS) for the years 2005 to 2016, the effect is identified by comparing state border-straddling county pairs in cases where one state unilaterally increases its minimum wage. This strategy represents an improvement over traditional methods used in minimum wage literature because it accounts for heterogeneous local employment trends and observations are not spatially or temporally correlated. The results suggest labor force participation falls while school enrollment rises.