This page and its subpage principally address the mistaken belief that generally reducing adverse criminal justice outcomes (included adverse interactions with the police) will tend to reduce (a) relative racial differences in rates of experiencing the outcomes (as commonly presented in terms of the ratio of the Black rate to the white rate) and (b) the proportion Blacks make up of persons experiencing the outcomes (compared with the proportion Blacks make up of the population potentially experiencing the outcomes). As I have explained in many places since 1996, the opposite is the case.
That is, as I have explained in scores of places with respect to any favorable or adverse outcome since 1987, when two groups differ in their susceptibility to an outcome, generally reducing the outcome, while tending to reduce relative differences in rates of avoiding the outcome (i.e., experiencing the opposite outcome), tends to increase relative difference in rates of experiencing the outcome itself. Correspondingly, reducing the outcome, while tending to increase the proportion the more susceptible group makes up of persons avoiding the outcome (thus reducing all measures of difference between the proportion the group makes up of the population and the proportion it makes up of persons avoiding the outcome), tends also to increase the proportion the group makes up of persons experiencing the outcome itself (thus increasing all measures of difference between the proportion the group makes up of the population and the proportion it makes up of persons experiencing the outcome).
But most people, including most statisticians and other data analysts, are unaware that it is even possible for the relative difference in a favorable outcome and the relative difference in the corresponding adverse outcome to change in opposite directions as the prevalence of an outcome changes, much less that such pattern tends to occur systematically. And most persons who specialize in the analysis of demographic differences – whether regarding criminal justice, school discipline, borrowing, or voter requirement – mistakenly believe that reducing an adverse outcome will tend to reduce, rather than increase, (a) and (b) for the outcome.
The failure to understand that it is even possible for the relative difference in a favorable outcome and the relative difference in the adverse outcome to change in opposite as the prevalence of the outcomes change is close to universal regardless of the type of outcome at issue. In fact, so far as the published record reveals, no one has ever recognized such possibility save as a result of my work (though, inasmuch as the pattern is evident in so many kinds of data, I assume that some observers have recognized the pattern on their own even if such recognition as not been reflected in a published work). The extent to which observers mistakenly believe that reducing an adverse outcome will tend to reduce (a) and (b) for the outcome (as distinguished from simply having no view on the matter) varies. In general, the more an observer specializes in the analysis of demographic differences – and the more an observer is exposed to discussion of patterns of demographic differences (which commonly reflect the mistaken view) – the more likely the observer is to believe that reducing an adverse outcome will tend to reduce (a) and (b) for the outcome.
Criminal justice is an area where the mistaken belief that reducing adverse outcomes will tend to reduce (a) and (b) for the outcomes is pervasive. The fact that a person is a criminologist or studying criminology almost certainly means that the person mistakenly believe reducing adverse outcomes will tend to reduce (a) and (b) for the outcomes.
There exists a small industry comprised of expert monitors and persons seeking to be expert monitors of consent decrees arising from claims of discriminatory policing. One can find online the applications of various entities seeking to monitor decrees in U.S. v. City of Ferguson and the U.S. v. Baltimore Police Department, both of which decrees are premised on the mistaken belief that generally reducing adverse criminal justice outcomes will tend to reduce (a) and (b) for the outcomes. The applications commonly emphasize the expertise the applicant entity can provide with respect to the analysis of data. One can take for granted, however, that all the persons providing that expertise are unaware that generally reducing adverse criminal justice outcomes will tend to increase (a) and (b) for the outcomes and most or all mistakenly believe that reducing the outcomes will tend to reduce (a) and (b) for the outcomes. Otherwise, one can expect the application to reflect the correct understanding.
The cost of the monitoring is not insubstantial. The Venable applicant that was accepted for monitoring the Baltimore decree calls for a maximum yearly fee of 1.475million, which is apparently the average amount being charged. In the case of the Ferguson decree, the application of the Patton Boggs firms that secured the monitor role indicates that the parties had agreed to a budget not to exceed $1.25 million over the first five years or $350,000 for any single year. I have not looked into what has actually been charged for the Ferguson monitoring.
In the Ferguson case, the monitor is schedule to give status report that is viewable by the public on October 7, 2021, and comments regarding the matter may be submitted by October 5. Time permitting, I may submit a comment requesting to address whether generally reducing adverse outcomes should reduce or increase (a) and (b) for the outcomes and to discuss available data showing what in fact has occurred.
It remains to be seen whether, in the event that data become available in either case that show that general reductions in adverse criminal justice outcomes were accompanied by increases in (a) and (b) for the outcomes, those increases will be discussed as something that occurred despite the general reductions or some that, contrary to the original expectations of the parties, the courts, and the monitors, the increase were something that numerate observers should have expected to happen.