Will increasing the number of minority and women police officers make law enforcement more effective by drawing on abilities that have gone untapped and creating better contact with communities and victims? Or will standards have to be lowered too far before large numbers of minorities and women can be hired? Using cross-sectional time-series data for U.S. cities for 1987, 1990, and 1993, I find that hiring more black and minority police officers increases crime rates, but this apparently arises because lower hiring standards involved in recruiting more minority officers reduces the quality of both new minority and new nonminority officers. The most adverse effects of these hiring policies have occurred in the areas most heavily populated by blacks. There is no consistent evidence that crime rates rise when more women are hired, and this raises questions about whether norming tests or altering their content to create equal pass rates is preferable. The article examines how the changing composition of police departments affects such measures as the murder of and assaults against police officers. (JEL J72, K14, H42)
Using preferential standards to aid minority groups is frequently justified as rectifying past wrongs. Yet, since Richmond v. Croson Co. ,  the U.S. Supreme Court has held that these preferences must pass the difficult "strict scrutiny test" and will be invalidated unless they promote a "compelling" governmental interest. Correcting "societal discrimination" was not viewed as a compelling interest. Remedial efforts to rectify past discrimination will only be approved if narrowly tailored to correct specific instances of discrimination. The question of what goals constitute a sufficiently "compelling" interest has never been clearly specified by the Supreme Court, though in a very closely decided case it reversed its own past decision that Federal Communication Commission (FCC) allocation of licenses by race is acceptable to promote diversity in entertainment and news programming and applied these high standards of strict scrutiny and "compelling" interest to federal building projects. 
The standards set by the Supreme Court in Richmond and Adarand were motivated by the desire that "The [strict scrutiny] test also ensures that the means chosen 'fit' this compelling goal so closely that there is little or no possibility that the motive for the classification was illegitimate racial prejudice or stereotype."  One can hypothesize what compelling goals would meet these standards where there is "little or no possibility" that an ulterior race-based motive might be the true motivation behind an affirmative action rule, but the most obvious case would be when the racial preferences actually help to further the central purpose of the governmental agency.  In the case of police, this means that minority police officers are being employed not because diversity is intrinsically valued but because it is believed to help lower the crime rate.
The potential law enforcement advantages from multiracial or female officers seem obvious. Minority police officers may be more effective in minority areas simply because residents could be more forthcoming about information that will lead to arrests and convictions or because of the officers' ability to serve as undercover agents. Trust is also important for other reasons, as reports of riots erupting after white police officers have shot a black man may attest.  Officers from a community may also be better at understanding the behavior of criminals in those areas or even something as basic as understanding the language of immigrants.  In any event, police efforts to reduce crime are surely dependent on the help that they receive from the community (Wilson ).
Rape victims or women abused by their spouses plausibly find it easier to discuss the traumatic events with women officers. Without female officers, many attacks against women may go undetected--thus lowering the expected penalty from attacking women and resulting in even more attacks. …