Table 1 Sample sizes with different treatment effects and control group quit rates
From: Protocol for the Proactive Or Reactive Telephone Smoking CeSsation Support (PORTSSS) trial
Control (reactive support, no offer of NRT) group quit rate at 6 months (%) | Comparison "group" quit rate at 6 months (%) | Intervention "group" quit rate at 6 months (%) | Odds ratio for each treatment effect (proactive vs reactive, NRT vs no NRT) | Power | Required sample size per group (total for 4 groups) |
|---|---|---|---|---|---|
12%* | 14% | 18.6% | 1.4 | 80% | 536 (2142) |
12%* | 14.5% | 20.3% | 1.5 | 80% | 355 (1420) |
12% | 14.5% | 20.3% | 1.5 | 90% | 468 (1872) |
8%** | 9.5% | 12.8% | 1.4 | 80% | 739 (2956) |
8%** | 10% | 14% | 1.5 | 80% | 489 (1956) |
8%** | 10% | 14% | 1.5 | 90% | 644 (2576) |