Implicit Bias Training for Police: Evaluating Impacts on Enforcement Disparities

Abstract

Objective: The purpose of this study was to estimate the behavioral impacts of training police officers in implicit bias awareness and management. Hypotheses: Training police in implicit bias reduces racial and ethnic disparities in stops, arrests, summonses, frisks, searches, and/or use of force. Method: A cluster randomized controlled trial using the stepped wedge design was applied to 14,471 officers in the New York City Police Department, with a 1-day training delivered to clusters of police commands between May 2018 and April 2019 and outcomes measured with police records of individual events from April 2018 to May 2019. Police records were supplemented with survey data on 1,973 officers matched to administrative data. For each type of enforcement action, the likelihood that the action involved or was taken against Black or Hispanic suspects, respectively, relative to White suspects was estimated, controlling for potential confounders. Additional analysis allowed for estimating training effects of different magnitudes for Black, Hispanic, and White officers and for officers with greater motivation to act without prejudice or greater concern about discrimination. Results: None of the estimated training effects achieved statistical significance at the.05 level. Conclusions: Isolated and weak evidence of behavioral impacts of the training was detected. Several explanations for the null findings are considered.