Community-based Health Intervention Trials: An Overview of Methodological Issues

Health interventions applied on a community-wide basis have come into increasing use in public health and epidemiologic research over the past several decades. With the promise of community-based interventions as a means of increasing the generalizability of health program benefits, providing information to health policy-makers beyond that obtained by individual-based clinical trials, and improving health in a cost-effective manner (1), researchers have forged ahead to expose numerous communities to large-scale health interventions. The emergence of community health intervention trials represents a shift in health research from investigations that focus primarily on the individual to those that focus on larger community groups. This emphasis on interventions focusing on communities has created distinct methodological challenges for researchers. In this paper, we provide an overview of major methodological issues pertaining to community-based intervention trials as compared with the more traditional, individualbased clinical intervention trials. Although the boundaries distinguishing community-based research from individualbased research are not always easily discernable (2), the well-established literature on individual-based clinical trials can stand as a useful point of comparison against the relatively recent development of community-based health trials. The methodological issues we focus on here include randomization, statistical power, cohort versus cross-sectional assessments, secular trends, outcome measurement, and the role of conceptualization in methodological design. Furthermore, the balance between scientific methodology and other practical issues (e.g., economic and sociopolitical issues) is discussed.