Efficacy of web-based personalized normative feedback: a two-year randomized controlled trial

Abstract

Objective: Web-based brief alcohol interventions have the potential to reach a large number of individuals at low cost; however, few controlled evaluations have been conducted to date. The present study was designed to evaluate the efficacy of gender-specific versus gender-nonspecific personalized normative feedback (PNF) with single versus biannual administration in a 2-year randomized controlled trial targeting a large sample of heavy-drinking college students.

Method: Participants included 818 freshmen (57.6% women; 42% non-Caucasian) who reported 1 or more heavy-drinking episodes in the previous month at baseline. Participants were randomly assigned in a 2 (gender-specific vs. gender-nonspecific PNF) × 2 (single vs. biannual administration of PNF) + 1 (attention control) design. Assessments occurred every 6 months for a 2-year period.

Results: Results from hierarchical generalized linear models provided modest effects on weekly drinking and alcohol-related problems but not on heavy episodic drinking. Relative to control, gender-specific biannual PNF was associated with reductions over time in weekly drinking (d = -0.16, 95% CI [-0.02, -0.31]), and this effect was partially mediated by changes in perceived norms. For women, but not men, gender-specific biannual PNF was associated with reductions over time in alcohol-related problems relative to control (d = -0.29, 95% CI [-0.15, -0.58]). Few other effects were evident.

Conclusions: The present research provides modest support for the use of biannually administered web-based gender-specific PNF as an alternative to more costly indicated prevention strategies.

(c) 2010 APA, all rights reserved.

Figures

Figure 1

Participant flow chart. GSF = gender-specific feedback; bac = blood alcohol content; GNSF = gender-nonspecific feedback; mo = months.

Figure 2

Unadjusted means and standard deviations by condition for perceived norms and drinking outcomes. GNS = gender-nonspecific; GS = gender-specific; RAPI = Rutgers Alcohol Problem Index (used to assess alcohol-related problems); mos = months; DDQ = Daily Drinking Questionnaire (used to assess drinks per week); NSNORM = gender-nonspecific perceived norms; SSNORM = gender-specific perceived norms; HED = heavy episodic drinking.

Figure 3

Effect sizes (ds) and 95% confidence intervals for Treatment versus Control × Time interactions for drinks per week, alcohol-related problems, and heavy episodic drinking. GNS = gender-nonspecific; GS = gender-specific.

Figure 4

Effect sizes (ds) and 95% confidence intervals for Treatment versus Control × Time interactions for gender-specific (GS) perceived norms and gender-nonspecific (GNS) perceived norms.