Appropriate research designs for evaluating community-level alcohol interventions: what next?

AIM The aim of this study was to explore the logistical and methodological strengths and weaknesses of some of the more common research designs which can be used to evaluate the impact of system- or population-level approaches for reducing alcohol-related harms. METHOD This paper identifies studies that have evaluated system or population approaches to reduce alcohol-related harms. It highlights the tension caused by a desire for the most rigorous research designs, such as randomized controlled trials (RCTs), the most potentially efficacious interventions and the practical problems in applying the RCT to population-level research. Alternative research designs, which possess methodological rigour and are more feasible, are identified and described. The design with the strongest methodological characteristics and feasibility in allowing the evaluation of population interventions is considered to be the multiple baseline. RESULTS The multiple baseline design addresses potential problems of sample sizes, selection bias, the suitability and baseline stability of outcome measures, statistical analyses and the practicalities of conducting rigorous research in system- or population-level settings. CONCLUSION The multiple baseline design has the capacity to allow methodologically and statistically stringent evaluations with relatively small sample sizes, low cost and fewer of the complications imposed by RCTs. Like all research designs it has limitations, but arguably represents the most practical and methodologically rigorous approach to the evaluation of system- or population-level strategies.