Measuring police effectiveness is a daunting task at both the agency and at the individual officer levels. At the macro level, studies indicate that some proactive policing strategies can lower crime rates, but there are many other factors that also affect crime so there is no one-size-fits-all answer to what police can do to lower incidents of crime in any given area. On the individual officer level, departments usually measure tangible production—e.g., tickets issued, arrests made, individuals contacted via police stops—but that doesn’t say what effect, if any, those actions had on the community well-being. So, while departments want to lower crime rates and enhance community well-being, they usually evaluate officers on actions that have no proven bearing on either metric. Many officers are thus incentivized to make certain contacts with individuals irrespective of whether or not it will ultimately benefit the community. As a result, the costs of those encounters with the public are often ignored or overlooked as the police go about their business.

A new collaborative article in the Proceedings of the National Academy of Sciences measures the criminogenic effects of pedestrian stops among non-white* adolescent males. Put simply, the researchers measured whether police stops of male adolescents of color had an effect on their likelihood to commit crimes in the future (measured as “delinquency"). The study also measured whether the police encounters had the desired deterrent effect on future criminal behavior. What the study found is troubling, given that police agencies often employ proactive strategies like officer contact to deter crimes.

The research indicates that a pedestrian stop of an adolescent male of color slightly increased the likelihood of future delinquent behavior, regardless of the young man’s previous engagement in delinquent activities. The research also indicates that multiple pedestrian stops further increases the likelihood of future delinquent behavior. The research neither indicated that police stops had the desired deterrent effect on delinquency nor that delinquent behavior had an effect on the number of police stops. That is, these stops had a one-way effect on delinquency, and it was not the good way. This evidence suggests that certain common types of proactive policing amounts to what we at Cato have dubbed “self-defeating policing.”

One doesn’t have to believe that police act maliciously or in an intentionally racist manner to understand that policing can have unintended, negative effects on the communities officers try to serve. This article is important because it tries to quantify the psychological and other social costs of policing tactics on those who experience them. Kudos to the researchers and authors of this important article. More work like this could have a significant impact on the future of policing.

You can read the abstract and download the paper here.

 *N.B. Adolescent males of color were singled out because they are far more likely than white adolescent boys or females of any race to be stopped by police while on foot. It should be noted, however, that the reactions to stops did not vary among the races measured (black, Latino, and multi-racial).