Table 2.
Effect sizes and homogeneity statistics for college drinking interventions vs. controls, over four follow-up intervals.
| Outcome | k of interventions | Weighed mean d (and 95% confidence interval) | Homogeneity of effect sizes | Variation due to heterogeneity I2 index (and 95% uncertainty interval) | ||
|---|---|---|---|---|---|---|
| Fixed effects | Random effects | Q | P | |||
| Immediate Posttest (≤ 3 weeks) | ||||||
| Quantity | 18 | 0.19 (0.07, 0.32) | 0.20 (0.06, 0.33) | 20.53 | .36 | 9% (0%, 45%) |
| Quantity, specific intervals/drinking daysa | 19 | 0.03 (-0.05, 0.11) | 0.03 (-0.05, 0.11) | 13.92 | .73 | 0% |
| Maximum quantity | 6 | 0.05 (-0.12, 0.23) | 0.04 (-0.19, 0.28) | 8.96 | .11 | 44% (0%, 78%) |
| Frequency of heavy drinkinga | 13 | 0.17 (0.03, 0.31) | 0.18 (0.02, 0.35) | 15.04 | .24 | 20% (0%, 58%) |
| Frequency of drinking daysa | 5 | -0.08 (-0.26, 0.10) | -0.08 (-0.26, 0.10) | 3.14 | .53 | 0% |
| Peak BAC | 5 | 0.41 (0.26, 0.57) | 0.36 (0.03, 0.69) | 11.66 | .02 | 66% (10%, 87%) |
| Problems | 9 | 0.02 (-0.08, 0.12) | 0.02 (-0.08, 0.13) | 8.91 | .35 | 21% (0%, 64%) |
| Short-term Follow-up (4 – 13 weeks) | ||||||
| Quantitya | 38 | 0.13 (0.06, 0.19) | 0.14 (0.07, 0.22) | 44.98 | .17 | 18% (0%, 45%) |
| Quality, specific intervals/drinking days | 22 | 0.13 (0.05, 0.21) | 0.15 (0.06, 0.21) | 23.17 | .33 | 9% (0%, 44%) |
| Maximum quantity | 8 | 0.08 (-0.04, 0.20) | 0.07 (-0.07, 0.21) | 8.74 | .27 | 20% (0%, 62%) |
| Frequency of heavy drinkinga | 27 | 0.18 (0.10, 0.26) | 0.21 (0.12, 0.30) | 31.03 | .23 | 16% (0%, 48%) |
| Frequency of drinking days | 13 | 0.02 (-0.07, 0.10) | 0.08 (-0.06, 0.22) | 19.68 | .07 | 39% (0%, 68%) |
| Peak BACa | 15 | 0.13 (0.04, 0.21) | 0.13 (0.04, 0.21) | 7.36 | .92 | 0% |
| Composite alcohol consumption | 10 | 0.03 (-0.07, 0.12) | 0.04 (-0.10, 0.18) | 16.72 | .06 | 46% (0%, 74%) |
| Problems | 33 | 0.15 (0.08, 0.21) | 0.16 (0.08, 0.25) | 46.31 | .05 | 31% (0%, 55%) |
| Intermediate Follow-up (14 – 26 weeks) | ||||||
| Quantitya | 19 | 0.11 (0.02, 0.20) | 0.11 (0.02, 0.20) | 14.60 | .69 | 0% |
| Quantity, specific intervals/drinking days | 8 | 0.19 (0.08, 0.31) | 0.20 (0.06, 0.34) | 10.02 | .19 | 30% (0%, 69%) |
| Frequency of heavy drinking | 12 | 0.11 (0.01, 0.22) | 0.11 (0.01, 0.22) | 11.08 | .44 | 1% (0%, 11%) |
| Frequency of drinking days | 5 | -0.03 (-0.16, 0.10) | -0.03 (-0.16, 0.10) | 0.25 | .99 | 0% |
| Peak BAC | 12 | 0.10 (-0.01, 0.20) | 0.11 (-0.01, 0.22) | 11.93 | .37 | 8% (0%, 46%) |
| Composite alcohol consumption | 5 | 0.06 (-0.08, 0.19) | 0.06 (-0.08, 0.19) | 0.92 | .92 | 0% |
| Problems | 12 | 0.22 (0.12, 0.32) | 0.22 (0.12, 0.32) | 8.04 | .71 | 0% |
| Long-term Follow-up (27 – 195 weeks) | ||||||
| Quantitya | 14 | 0.06 (-0.04, 0.16) | 0.06 (-0.04, 0.16) | 8.32 | .74 | 0% |
| Quantity, specific intervals/drinking days | 7 | 0.07 (-0.05, 0.19) | 0.07 (-0.05, 0.19) | 3.99 | .68 | 0% |
| Frequency of heavy drinking | 8 | -0.04 (-0.16, 0.08) | -0.04 (-0.16, 0.08) | 6.98 | .44 | 0% |
| Frequency of drinking days | 5 | 0.16 (0.03, 0.30) | 0.16 (0.03, 0.30) | 3.06 | .55 | 0% |
| Peak BAC | 10 | 0.09 (-0.02, 0.20) | 0.09 (-0.02, 0.20) | 10.53 | .31 | 15% (0%, 56%) |
| Typical BAC | 5 | -0.01 (-0.16, 0.14) | -0.01 (-0.16, 0.14) | 3.50 | .48 | 0% |
| Composite alcohol consumptiona | 5 | 0.11 (-0.05, 0.27) | 0.11 (-0.05, 0.27) | 1.00 | .91 | 0% |
| Problemsa | 16 | 0.14 (0.06, 0.22) | 0.12 (0.01, 0.23) | 24.19 | .06 | 38% (0%, 66%) |
Note. BAC = blood alcohol concentration
a
Outliers were excluded.