Table 3.
Means and Differences between Conditions on Drinking Variables across Time
| PFI Mean (SD) |
AO Mean (SD) |
PFI vs. AO Independent samples t-test for 1m and 9m |
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Measure | Base- line |
1m | 3m | 6m | 9m | Base- line |
1m | 3m | 6m | 9m | 1m Mean Diff |
t (d) | 9m Mean Diff |
t (d) |
| Quantity | 23.06 (20.17) | 14.34 (13.34) | 10.84 (12.36) | 10.28 (12.21) | 8.38 (12.88) | 25.50 (23.07) | 18.89 (15.18) | 17.21 (16.67) | 14.01 (13.56) | 14.40 (14.54) | 4.56 | 2.01* (2.93) | 6.22 | 1.50 (3.38) |
| Frequency | 4.07 (1.74) | 3.48 (2.39) | 2.99 (2.94) | 2.43 (2.94) | 2.01 (2.93) | 4.77 (2.02) | 4.35 (2.40) | 4.19 (3.11) | 3.56 (2.82) | 3.46 (3.19) | 0.87 | 1.83 (1.33) | 1.45 | 1.36 (1.59) |
| HD days | 2.12 (1.9) | 1.31 (1.84) | 1.16 (1.56) | 1.07 (1.82) | 0.58 (1.66) | 2.31 (2.24) | 1.92 (2.17) | 1.31 (1.70) | 1.14 (1.83) | 1.40 (1.77) | 0.61 | 1.87 (0.98) | 0.83 | 2.22* (1.27) |
| Prop HD days | 0.51 (.37) | 0.35 (.41) | 0.35 (.38) | 0.26 (.41) | 0.21 (.40) | 0.45 (.38) | 0.39 (.39) | 0.24 (.34) | 0.24 (.40) | 0.30 (.42) | 0.05 | 0.67 (0.25) | 0.09 | 1.22 (0.38) |
| Peak drinks | 8.06 (7.02) | 4.94 (3.83) | 4.15 (3.69) | 3.63 (4.08) | 3.79 (4.62) | 8.03 (7.90) | 6.09 (4.39) | 5.43 (4.62) | 4.25 (4.58) | 4.52 (5.110 | 1.06 | 1.04 (0.27) | 0.54 | 0.40 (0.58) |
| Typical BAC | 0.07 (.07) | 0.05 (.05) | 0.04 (.05) | 0.03 (.06) | 0.05 (.07) | 0.17 (.07) | 0.05 (.06) | 0.05 (.07) | 0.05 (.07) | 0.03 (.07) | 0.01 | 0.67 (0.07) | −0.02 | −0.70 (−0.13) |
| Problems | 7.66 (5.02) | 6.24 (6.05) | 5.30 (6.34) | 6.74 (7.87) | 6.13 (8.59) | 8.34 (5.70) | 7.74 (6.49) | 6.78 (7.67) | 6.04 (7.31) | 5.86 (8.75) | 1.50 | 1.30 (1.40) | −.270 | −0.12 (−0.18) |
Note. PFI = personalized feedback intervention group, AO = assessment only group, Diff = difference, Quantity = total number of drinks, Frequency = total number of drinking days, HD days = number of heavy drinking days, Prop HD days = proportion of heavy drinking days, Peak drinks = maximum number of drinks, Typical BAC = typical blood alcohol concentration, Problems = number of alcohol-related problems experienced, 1m = 1-month, 3m = 3-month, 6m = 6-month, 9m = 9-month, d = Cohen’s d. Also note that results reported for peak drinking at 1 month reflect sex-adjusted means. Other means were not adjusted because sex was not a significant predictor.