This chapter presents the results of a survey experiment testing cooperation interventions in Baltimore. It describes existing efforts in the city to promote cooperation with the police and how police rely on information from witnesses. The survey experiment entails respondents viewing and responding to a professionally produced fictional news report of a shooting with experimental variations to test the various interventions. The results show police encouraging cooperators to call an anonymous tip line (as opposed to a non-anonymous line) as well as creating awareness of cooperation norms both increase information sharing. The police commander portrayed in the news report being the same race as the respondent does not change the amount information that they are willing to share. The chapter also discusses the mechanisms of how support for cooperation exists in Baltimore despite distrust of the police.

This chapter theorizes how interventions employed by police and community safety advocates might promote cooperation. The evaluation focuses on two interventions that plausibly reverse cycles of silence: facilitating cooperator anonymity to reduce the risk involved in information sharing and creating awareness of support for cooperation to strengthen the perceived norms favoring information sharing. Given that these interventions do not address distrust in the police, which places a ceiling on cooperation support, the evaluation also includes the trust-based intervention of exposing citizens to police officers of the same race or ethnicity. The chapter concludes with enumerating principles that should be considered when evaluating the appropriateness of implementing interventions to promote cooperation.