It has been suggested that PFIs may have a greater effect for heavier drinkers than for lighter drinkers because feedback for the former group is more extreme (Walters & Neighbors, 2005). However, studies have been inconsistent in their findings among non-mandated students (Larimer et al., 2007; Murphy et al., 2001). Murphy et al. compared the efficacy of a PFI within the context of a BMI and an educational intervention to an assessment-only control on weekly alcohol consumption and binge drinking among 84 volunteer high-risk students. They found that the PFI contributed to greater reductions in alcohol use and heavy drinking at the 3-month and 9-month follow-ups among those students who were heavier drinkers at baseline. This finding needs to be interpreted with caution because Murphy et al. did not formerly test the interaction between baseline drinking and PFI conditions, and used α = .15 as the Type I error rate due to a small sample size. In contrast, in a large sample of volunteer students, Larimer et al. did not find that severity of baseline drinking moderated the efficacy of
