BMC Public Health 2005, 5:75 http://www.biomedcentral.com/1471-2458/5/75 tn100% e n it 80% s b a 60% s y ad 40% t en 20% c r eP 0% 12 0 1 Pre-treat Follow-up PFeigrcuernet 1days abstinent at follow-up Percent days abstinent at follow-up. Percent days abstinent at pre-treatment and follow-up for patients who received 0, 1 or 12 treatment sessions. The 0 treatment dropout group showed great improvement from pre-treatment to follow- up. The 1 session attendance dropout group had worse scores than did the 0 treatment group. These data suggest that most of the improvement in the full 12 session attend- ance group cannot be due to treatment. See also Figure 2. Figures 1 and 2 show pre-treatment and follow-up out- come data for the 0, 1 and 12 session groups. The figures shows large improvements in percent days abstinent (Fig- ure 1) and drinks per drinking day (Figure 2) for partici- pants who attended either 0, 1 or all 12 treatment sessions. The improvement in both measures is highly sig- nificant for all groups (Table 6). Participants who received either 0, 1 or 12 treatment sessions are displayed. Shown are the raw score means and the statistical tests and effect size estimates which were calculated using the Project MATCH transformed scores. Participants in the 0 and 1 treatment session groups dropped out and received little or no treatment. The participants who dropped out after one session (the 1 session group) had worse scores than the other groups at pre-treatment as well as follow-up on both measures. Additionally, at baseline the 0 treatment group's scores were noticeably worse than the 12 treatment group's scores on drinks per drinking day (t = 3.26, 395 df, p = .001). Effect sizes for all groups are also shown in Table 6. For percent days abstinence, those who dropped out before receiving any treatment had an effect size of 1.50, and those who attended all 12 sessions had an effect size of 2.04. For drinks per drinking day, there were effect sizes of 1.53 for the zero treatment group and 2.49 for the full y ad25 g in20 k n ir 15 d r e10 p s k 5 n i r D 0 1 0 12 Pre-treat Follow-up FDirginukrsep2er drinking day at follow-up Drinks per drinking day at follow-up. Drinks per drinking day at pre-treatment and follow-up for patients who received 0, 1 or 12 treatment sessions. The 0 treatment dropout group showed great improvement from pre-treatment to follow- up. The 1 session attendance dropout group had worse scores than did the 0 treatment group. These data suggest that most of the improvement in the full 12 session attend- ance group cannot be due to treatment. See also Figure 1. treatment group. The estimated no-treatment effect sizes as proportions of the full treatment response was .73 (1.50/2.04) for percent days abstinent and .61 (1.53/ 2.49) for drinks per drinking day. Figures 3 and 4 show the data for the 12 weeks of the treat- ment period. Improvement from pre-treatment to week 1 was statistically highly significant for all groups for both measures (Table 6). The estimated no-treatment effect sizes as proportions of the full treatment response was .85 (1.98/2.32) for percent days abstinent and .72 (2.10/ 2.91) for drinks per drinking day. Only the 12 session group showed significant improvement from week 1 to week 12 (Table 6). Change from week one to follow-up showed deterioration for the zero and full treatment groups for both measures. There were no significant differences between the zero treatment dropout group and the full treatment group from week 1 to follow up in percent days abstinent (t = .25, 395 df, p = .800) or in drinks per drinking day (t = 1.22, 395 df, p = .222). Discussion The results suggest that treatment was not particularly effective. The following lines of evidence point to this con- clusion. Correlations between treatment attendance and outcome were very small (as shown in Table 2). A median Page 6 of 11 (page number not for citation purposes)