Should the police use race as one of the characteristics upon which they make decisions about stopping and searching motorists or pedestrians? (The question assumes, of course, that the police are not operating from a description of a specific individual believed to be involved in a crime.) Among those who have answered “no” to a question of this sort is our nation’s Attorney General. Others think that the practice is OK, as long as it is consistent with efficient policing: after all, you wouldn’t want to focus lots of law enforcement on groups that are rare offenders, such as elderly women. But is it right that a black driver on I-95 in Maryland in the late 1990s was five times more likely to be subject to a search than was a white driver?
Those who take the “efficient policing” position often say that the disproportionate number of stops is OK, as long as the probability that a searched motorist is carrying contraband (in the case of anti-drug enforcement, the aim of most of the highway searches) is about the same for blacks as for whites. (This probability is sometimes called the “hit rate.”) By this reckoning, if only 5 percent of the blacks who are searched are found to be carrying drugs, while 20 percent of the whites searched are carrying, then the racial disparities in searches are not consistent with efficient policing and should be curtailed, eliminated, or reversed. On the other hand, if the hit rate for searches is about 20 percent for both groups, then the use of race as an indicator might be acceptable.
But I and my co-author, Michael Alexeev of Indiana University, think that this standard “efficient policing” story is mistaken, for reasons that I will mention after the “Continue reading…” link.