Methodological Challenges and Opportunities in Testing for Racial Discrimination in Policing

A large body of empirical research exists that attempts to determine whether or not police discriminate on the basis of race. We investigate whether the methods used typically produce valid inferences. We find that they often most likely do not and that results may diverge from reality in either direction, indicating discrimination when it is not present or alternatively indicating a lack of discrimination when it is in fact present. The reason for this is that tests make assumptions about police behavior that are often implausible. Because of this, the simplest forms of benchmark and outcome tests should not be used, although the problem is more general. We discuss several possible ways to improve inferences about the absence or presence of discrimination, such as employing matching or weighting techniques and using novel, computationally intensive methods.