Table.
Characteristics of reports of controlled trials published in five general medicine journals in 1998
| Characteristic of trial reports | Annals of Internal Medicine (n=20) | BMJ (n=48) | JAMA (n=47) | Lancet (n=82) | New England Journal of Medicine (n=83) |
|---|---|---|---|---|---|
| Parallel group trials | 18 (90.0) | 46 (95.8) | 45 (95.7) | 78 (95.1) | 78 (93.9) |
| Randomised individuals | 19 (95.0) | 42 (87.5) | 45 (95.7) | 81 (98.8) | 83 (100) |
| Tested pharmacological intervention | 13 (65.0) | 15 (31.3) | 30 (63.8) | 55 (67.1) | 61 (73.5) |
| Median total sample size (range) | 88 (35 to 1283) | 214 (11 to 17 187) | 197 (24 to 6605) | 382 (15 to 19 193) | 400 (20 to 10 948) |
Differences were significant for unit of randomisation (individuals v other, P=0.003), type of intervention (drugs v other, P<0.001), and sample size (P=0.004). Probability from χ2 and Kruskal-Wallis tests.