Using an SRE median split, the student with the lowest LR was identified and a high LR participant with the same sex and similar ethnicity and recent alcohol quantities and frequencies was selected. With >80% of eligible students agreeing to participate, the process continued until 500 individuals were enrolled. As <2% of UCSD students are AAs and smaller proportions are Malay, Filipino, Middle Eastern or other minorities, these subjects were sometimes matched with participants of different minority ethnicities. High and Low LR pairs were randomly assigned to the LRB, SOTA, and Control Groups stratified by sex, alcohol quantities and frequencies, and ethnicity, with fewer assigned as controls to optimize power for comparisons of outcomes for LRB and SOTA groups.
