Heather Mac Donald, National Review, March 3, 2015

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Justice’s Ferguson report allegedly will rest on a “disparate impact” analysis of Ferguson’s police practices. Disparate-impact analysis obviates the need to find intentional discrimination in a civil-rights case; a policy or practice can be wholly color-blind, but if, in its application, it falls more heavily on a particular racial group, it is illegal under certain federal regulations. {snip}

The Obama administration’s aggressive use of disparate-impact theory against schools for their disciplinary practices has been a disaster for classroom safety and order. That school-discipline crusade has meant that schools cannot remove unruly black students from the classroom under neutral behavioral codes without triggering potential legal liability, simply because more black students violate those codes. But as destructive as the application of disparate-impact theory to school authority has been, applying it broadly to law enforcement is a recipe for anarchy. There are few criminal laws that do not have a disparate impact on blacks, because the black crime rate is more elevated than the white crime rate. Black males between the ages of 14 and 17, for example, die from homicide nationally at nearly ten times the rate of white and Hispanic males of the same ages combined, because the black youth homicide rate is similarly skewed. Blacks commit property crimes at about three times the rate of their presence in the national population, according to arrest data. And although the topic has been virtually taboo in research circles, the few studies that have looked at driving behavior, including in New Jersey and North Carolina, suggest that black drivers violate traffic laws at a higher rate than whites do.

In Ferguson, blacks accounted for 86 percent of traffic stops in 2013 but make up 63 percent of the population, reports the New York Times. Such numbers are meaningless as a measure of police behavior, unless one considers the underlying rate of traffic offenses. If blacks are disproportionately represented among speeders, red-light runners, and drivers without updated vehicle registration, say, then their higher rate of being stopped simply means that the police are applying the traffic laws neutrally to lawbreakers. Do not expect the Justice Department to have performed such an analysis of driving behavior, however. And discovering the underlying rate of driving offenses is just the beginning of the analysis. The demographics of roadways can differ enormously from the residential population surrounding those roadways and even vary according to the time of day and the day of the week. Using a residential-population benchmark to evaluate traffic enforcement–which the Justice Department is certain to do–is illegitimate as either a research or a legal strategy.

The New York Times also notes that black drivers in Ferguson were twice as likely to be searched, even though searches of white drivers were more likely to turn up contraband. Again, such a statistic is meaningless unless one knows the underlying rate at which black and white drivers had outstanding warrants–which will trigger a search–and what their behavior was upon being stopped.

The absence of a valid benchmark for evaluating traffic enforcement undercuts any intentional-discrimination claim against the police. But the use of disparate-impact analysis could make it irrelevant to know whether blacks violate the traffic laws at a higher rate; the neutral application of those laws would nevertheless be a form of discrimination if blacks are disproportionately penalized under those laws. If that is in fact the tack that the Justice Department takes in the case, the Department is nevertheless certain to imply that the Ferguson police department is also deliberately discriminating against black drivers, because that is what the Democrats’ base demands.

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