Table 1 shows the means and standard deviations of the alcohol use outcome variables at the three time points for these two groups. The improved group reported significantly lower levels of HED and AP at baseline as well as the two follow-up assessments.11 Table 2 shows the within-person changes (mean changes, t values, and effect sizes) from baseline to 4 months, from 4 months to 15 months, and from baseline to 15 months post-intervention from paired t-tests. The improved group, compared to the non-improved group, showed reductions in the range of medium to large effect sizes (see Table 2; d = .68 - .77; d = .2, .5, and .8 for small, medium, and large effects; Cohen, 1988) from baseline to 4 months, followed by significant upward swings in the range of small to moderate effect sizes (d = .41 - .61). The initial reduction in AP was maintained over time for the improved group; however, the initial reduction in HED was not maintained over the long-term. When followed-up at 15 months post intervention, the improved group reported lower levels
