This chapter introduces a research design to study the effects of community policing. The chapter introduces the Metaketa model of multi-site trials, which are used to answer questions relevant to policy using coordinated experiments in which the same intervention is randomly assigned to units in multiple contexts and the same outcomes are measured to estimate effects. In specific, the chapter introduces how the six countries were selected for study and describes their characteristics in terms of crime and policing and then how the interventions were selected and harmonized across the settings and how they compare to community policing policies in the world. The remainder of the chapter details the experimental design, from how police beats and units are sampled, how community policing intervention was randomly assigned, how outcomes were measured and harmonized, how effects were estimated for each site and then averaging across sites, and how we planned to address threats to inference.

In an effort to assess the generalizability of treatment effects across contexts, scholars (or teams of scholars) are increasingly conducting experiments around the same research questions in multiple country and subnational contexts. In this chapter, we categorize recent and ongoing efforts to conduct cross-context experiments into three types: “uncoordinated,” “coordinated, sequential,” and “coordinated, simultaneous.” We discuss some practical trade-offs across these types, arguing that coordinated cross-context designs offer the most promise for meta-analyses. We then draw attention to four areas in which the current approaches arguably all fall short in facilitating cumulative learning about treatment effects and treatment effect heterogeneity across contexts. We conclude by proposing some ways forward to continue improving our approach to learning about generalizability across contexts.