Evidence-based health promotion and prevention in settings: Which types of study designs are needed?

Health promotion and health prevention are cornerstones of public health. In Germany, a draft health prevention law was rejected in 2013, partly because it almost exclusively focused on measures at the individual level. Many health promotion and prevention measures, by contrast, (also) address the societal level and the environment, but there are few robust studies on their effectiveness, not least because of a lack of resources, the complexity of the measures, or randomisation problems. For example, regulations that protect non-smokers from smoke are subject to political processes where the majority of decision-makers would decline consent for randomisation. In a workshop at the 15th Annual Meeting of the German Network for Evidence-based Medicine (DNEbM) two case studies on controlled before-and-after studies (CBA) and interrupted time series (ITS) were developed by the audience as possible alternatives to randomised controlled trials for the evaluation of health promotion and health prevention programmes. The suggestions made by the audience were compared to the study designs chosen in published studies, and the strengths and weaknesses of the different study designs were discussed. The wide array of suggestions for effectiveness studies illustrated the potential of evidence based health promotion and prevention, but also the specific challenges to be faced.