Mechanisms of change in control group drinking in clinical trials of brief alcohol intervention: Implications for bias toward the null

Reductions in control group consumption over time that are possibly related to research design affect the impact of brief alcohol interventions (BAI) in clinical settings.We conducted a systematic review to identify research design factors that may contribute to control group change, strategies to limit these effects and implications for researchers. Studies with control group n > 30 were selected if they published baseline and outcome...