Analysis of baseline by treatment interactions in a drug prevention and health promotion program for high school male athletes

This paper investigates baseline by treatment interactions (BTI) of a randomized anabolic steroid prevention program delivered to high school football players. Baseline by treatment interactions occur when a participant's score on an outcome variable is associated with both their pretreatment standing on the outcome variable and the treatment itself. The program was delivered to 31 high school football teams (Control=16, Treatment=15) in Oregon and Washington over the course of 3 years (Total N=3207). Although most interactions were nonsignificant, consistent baseline by treatment interactions were obtained for knowledge of the effects of steroid use and intentions to use steroids. Both of these interactions were beneficial in that they increased the effectiveness of the program for participants lower in knowledge and higher in intentions at baseline.