My goal is to demonstrate the value of evidence-informed law through an examination of its influence upon issues that have been central to recent discussions about the police. The first advantage of evidence- informed law is that it draws upon social science theories to suggest possible alternatives to traditional legal frameworks. The second advantage is that through social science research the value of such alternative frameworks can be validated or falsified. Hence, when legal frameworks are implemented their consequences are known. In the case of the police empirical research has shown that the traditional deterrence model is not the only framework through which the police can operate. They can also exercise authority based upon their legitimacy, if and when they are legitimate. Further, research suggests that there are ways for the police to create and maintain their legitimacy while enforcing the law. The way for them to do so is to police in ways that people experience as procedurally just. This second factual statement is the focus of this paper. At this time, the statement that the police can heighten public trust during personal encounters if they act in ways people think are fair is contested. The results of a panel study of police-citizen interactions with young men in New York City are used to test whether experiences with the police change the perceived legitimacy of the police. In particular, does fair treatment increase trust? This question is central to arguing that the police can build trust if they change how they police.
(Author abstract provided.)