Table 3.
Quality of Study Methodology and Reporting
| 1980–1998 | 1999–2005 | All | ||||
|---|---|---|---|---|---|---|
| n | % | n | % | n | % | |
| Sample description | ||||||
| Reported number approached to participate | 88 | 36.5 | 112 | 45.3 | 200 | 41.0 |
| Reported number initially participating* | 210 | 87.1 | 232 | 93.9 | 442 | 90.2 |
| Compared characteristics of participants to eligible non- participants | 17 | 7.1 | 19 | 7.7 | 36 | 7.4 |
| Reported number dropping out of treatment | 101 | 41.9 | 116 | 47.0 | 217 | 44.5 |
| Research Design | ||||||
| One group post test only | 10 | 4.1 | 7 | 2.8 | 17 | 3.5 |
| One group pre and post test | 36 | 14.9 | 58 | 23.5 | 94 | 19.3 |
| Nonequivalent control group without matching or statistical control | 26 | 10.8 | 13 | 5.3 | 39 | 8.0 |
| Nonequivalent control group with matching or statistical control | 9 | 3.7 | 4 | 1.6 | 13 | 2.7 |
| Randomized experiment | 150 | 62.2 | 157 | 63.6 | 307 | 62.9 |
| Other design/design not indicated | 10 | 4.1 | 8 | 3.2 | 18 | 3.7 |
| Quality of randomization, for randomized experiments (n = 307)*b | ||||||
| Randomization implied but not stated | 2 | 1.3 | 1 | 0.6 | 3 | 1.0 |
| Method only stated to be randomized | 88 | 58.7 | 81 | 51.6 | 169 | 55.0 |
| Randomization procedure described but no measures to prevent subterfuge included | 42 | 28.0 | 37 | 23.6 | 79 | 25.7 |
| Randomization procedure described and measures to prevent subterfuge included | 18 | 12.0 | 38 | 24.2 | 56 | 18.2 |
| Intervention provision and specification | ||||||
| Manuals used to guide treatment (where applicable, n = 607 intervention conditions) | 87 | 27.3 | 93 | 32.5 | 182 | 30.0 |
| Intervention implementation assessed | ||||||
| Intervention monitoreda*** | 116 | 48.1 | 159 | 64.4 | 275 | 56.4 |
| Assessed immediate effects of interventiona | 26 | 10.8 | 28 | 11.3 | 54 | 11.1 |
| Additional intervention monitored | 37 | 15.3 | 41 | 16.6 | 78 | 16.0 |
| Contamination monitored (where applicable, n =368) | 20 | 8.2 | 25 | 10.1 | 45 | 12.2 |
| Process analyses conducted | ||||||
| Linked intervention elements or duration to outcomea | 38 | 15.7 | 37 | 15.0 | 75 | 15.4 |
| Examined mediating factorsa | 29 | 12.0 | 25 | 10.1 | 54 | 11.1 |
| Data Analyses | ||||||
| Groups compared for equivalence at baseline (where applicable, n = 375)** | 155 | 79.0 | 163 | 90.5 | 317 | 84.5 |
| Interaction between treatment condition and dropout status (re: study treatment or follow-up on pretreatment variables examined, where applicable n = 365) | 4 | 1.1 | 9 | 2.4 | 13 | 3.6 |
| Intent-to-treat analyses conducted** | 21 | 8.7 | 44 | 17.8 | 65 | 13.3 |
a
Categories not mutually exclusive.
b
df = 3.
*
p < .05.
**
p < .01.
***
p < .001.