A massive experiment has been conducted with law enforcement during the last couple of decades, with more minority and women officers being hired. But does increasing the number of minority and women police officers raise effectiveness by drawing on new untapped abilities, or are standards lowered too far in order to hire large numbers of minorities and women? I have argued here that the effect depends on the type of crime. The evidence for rape is mixed, with most results implying essentially no difference between male and female officers, though some estimates indicate that the actual changes in the composition of police departments helped reduce the number of rapes. However, for all other crimes, more black officers are associated with more crime, not less. But it would be a serious mistake not to realize that this simple relationship is masking that the new rules reduce the quality of new hires from other groups.
This does not say that there are not large potential benefits from minority police officers, but only that the new rules under which new officers have been hired have costs that outweigh the benefits.
So why do we observe different findings for minority and female officers? At least part of the difference appears to arise from how the hiring rules have been altered for the two groups. Physical strength tests involve norming, whereas written tests have been altered so as to produce equal pass rates across different groups. Norming
may allow lower-quality applicants in the protected category, but it at least does not lower the quality of all new recruits. The results suggest that if affirmative action is to be practiced, norming is the less costly way to go.
This raises a question that economists have thus far ignored: why are different types of affirmative action used in different settings? Why does academia use norming for admissions but police forces choose to alter the testing?
Changes in the composition of police departments have been accompanied by changes in the organization of police departments. Some of these changes--such as an increasing movement away from single-officer patrol units--is likely due to the presence of more female officers with less physical strength. Women officers are more likely to be assaulted than men, though their overall probability of death on the job is the same. Some preliminary evidence indicates that white women officers are more likely to shoot civilians and that black male officers are the least likely. The evidence is not consistent with the hypothesis that black officers are more effective at dealing with crime in predominately black areas. Instead, surprisingly, the results suggest that it is the most heavily black communities that are the most at risk from the increased crime produced by affirmative action policies.
Other recent research confirms the basic finding in this paper. While Donohue and Levitt  examine the issue of how nonwhite and white officers impact crime by members of their own group and by the other group, taking their sensitivity estimates of "crime rates to racial composition of the police force" and instead asking what happens to the total crime rate when a white officer is replaced by a nonwhite officer implies a large increase in violent crime in eight of their ten specifications. While they claim that nonwhite officers relatively reduce white crime and white officers relatively reduce nonwhite crime, the perverse effect that they find of nonwhite officers on nonwhite crime dominates in eight of their ten violent crime specifications.
As a warning for anyone doing future research: the evidence suggests that a great deal of caution needs to be exercised in aggregating different racial and/or gender groups. Not all nonwhite racial groups are the same, and not all men and women in a particular group are the same. Blacks, Hispanics, and Asians do not have the same impact on crime. Many differences between men and women on crime also disappear once different racial groups are subdivided by sex. The different results obtained from aggregated and disaggregated classifications strongly suggest that the most disaggregated classifications should be used whenever possible.
This article was initially motivated by the Supreme Court's recent rulings on affirmative action. Prior to consent decrees, the "best" police officers might not always have been hired, but the imposition of consent decrees appears to have increased crime, and the longer the decree was in effect the greater was the increase in crime. The hiring of minority officers thus does not appear to meet the difficult strict scrutiny standard set forth by the Supreme Court. There may be strong moral arguments for affirmative action, but crime reduction is not one of them. The results do suggest that if preferential hiring is to be practiced, changing testing standards is much more costly than norming.
Wednesday, July 08, 2009
Lott on affirmative action and crime: I ran across an interesting study by John Lott (DOES A HELPING HAND PUT OTHERS AT RISK?: AFFIRMATIVE ACTION, POLICE DEPARTMENTS, AND CRIME. By: Lott Jr., John R., Economic Inquiry, Apr2000, Vol. 38, Issue 2). Here is the conclusion:
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