When the principal's future alcohol consumption behavior, controlling for age, gender, education, and exam was regressed on the number of heavy drinking, moderate drinking, and abstaining contacts, each additional heavy drinking contact was found to significantly increase the likelihood that a principal drinks heavily by 18% (95% CI: 11% to 25%, p<0.001) and decreases the likelihood principal abstains by 7% (95% CI: 2% to 12%, p=0.009), but has no effect on moderate alcohol consumption behavior (CI: –8% to 1%, p=0.113). Conversely, each additional abstaining contact significantly reduces the likelihood of heavy drinking by 10% (95% CI: 4% to 15%, p=0.001), increases the likelihood of abstaining by 22% (95% CI: 17% to 28%), and also decreases the likelihood of moderate drinking by 11% (95% CI: 8% to 14%). Finally, each additional contact that drinks moderately has no significant effect on heavy drinking (95% CI: –2% to 7%, p=0.214) but it significantly decreases the probability of abstaining by 5% (95% CI: 2% to 9%) and increases the likelihood of moderate drinking by 6% (95% CI: 2% to 9%).
