Statistical considerations for the design, conduct and analysis of the efficacy of safe community interventions

In injury research, the use of community-level intervention trials is quite common. Often, it is the only practical method for assessing the efficacy of countermeasures or preventive interventions. ‘Safe Community’ is an intervention concept aimed at establishing community-level programs and policies to ensure the safety of inhabitants in a community. The methodological considerations in evaluating the efficacy of such interventions need to be well understood by injury researchers and policy makers. This paper presents various statistical issues that need to be considered in the design, conduct and analyses of community-level intervention trials. Only with an understanding of the statistical issues will such studies have the appropriate design, conduct and analysis, and thus be appropriately well-received, with the implication that they will indeed help to build safer communities.