Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Gail L. Rose

Second Advisor

John E. Helzer


Introduction: Unhealthy alcohol use is a substantial problem among college students and can lead to a variety of negative consequences. Commercially available web-based brief alcohol intervention (WBI) programs have demonstrated efficacy in a range of student groups and have been widely disseminated to colleges to address this issue. However, the majority of published WBI studies required participants to complete baseline research assessments (RA) about their alcohol use before the WBI and reactivity to the RA may have inflated WBI efficacy estimates in these studies. The present study tested whether there was an additive effect of RA administered online plus a WBI on alcohol consumption, alcohol consequences, and protective behaviors related to alcohol used in the past month compared to the effects of only a WBI. It was hypothesized that participants randomized to the RA+WBI condition would have significantly lower alcohol consumption in the past month, fewer alcohol-related problems, and use more protective behaviors related to alcohol consumption in the past month than participants randomized to the WBI only condition.

Methods: Undergraduate students (n= 856) from universities in the United States and Canada were recruited for this online study. Seventy percent of the sample was female and 82% were Caucasian. The sample had a mean age was 20.0. Sixty four percent (n= 547) of participants who were randomized completed the WBI. Sixty-eight percent completed the one month follow up questionnaire.

Results: Multiple regression analyses using 20 multiply imputed datasets revealed that there were no significant differences in groups at follow up on alcohol use measures, alcohol related problems, or protective behaviors used when controlling for variables with theoretical and statistical relevance to the models. A repeated measures analysis of covariance indicated that there was a significant decrease in peak estimated blood alcohol concentration from baseline to follow up, but no differential effect by randomization group. The results suggested there was a moderate effect of the WBI consistent with studies of WBI efficacy in the literature and that there were no substantial assessment reactivity effects.

Discussion: The current study contributes to the literature by identifying an experimental condition under which assessment reactivity may not be present and does not appear to cloud the detection of WBI efficacy when measured within subjects. The results indicate that WBI researchers may be justified in conducting brief pretreatment research assessments online to collect information about participant alcohol use without biasing within subjects estimates of WBI efficacy. Universities using these programs may likely observe similar effect sizes to those reported in the literature, however effectiveness studies are warranted.



Number of Pages

147 p.

Included in

Psychology Commons