How to increase diversity in the police is an unanswered question that has received significant political and media attention. One area of intervention is the recruitment process itself. This study reports the results of a randomized controlled trial (RCT) in a police force that was experiencing a disproportionate drop in minority applicants during one particular test. Drawing on insights from the literatures on stereotype threat, belonging uncertainty and values affirmation exercises, we redesigned the wording on the email inviting applicants to participate in the test. The results show a 50 per cent increase in the probability of passing the test for minority applicants in the treatment group, with no effect on white applicants. Therefore, the intervention closed the racial gap in the pass rate without lowering the recruitment standard or changing the assessment questions.