Note: The ratio of ratios measures the difference between the coach group and the email group in change in binge drinking frequency from baseline to follow-up 1. If the ratio of ratios is 1, there is no difference between the groups. If the ratio of ratios is below 1, coach is better than email, i.e., the coach group had a smaller change in binge drinking frequency. If the ratio of ratios is above 1, email is better than coach. In this figure, a nonzero slope is evidence of effect modification by the proposed moderator. P-values are for the relevant interaction term.