Table 2 Sample size assuming 5 % level of significance, 90 % power, 50 % relative risk reduction
Incidence of primary outcome in ‘no decision-support’ group | Incidence of primary outcome in ‘decision-support’ group | Relative risk | Total sample size required |
|---|---|---|---|
3 per 1000 | 1.5 per 1000 | 0.5 | 46,000 |
4 per 1000 | 2 per 1000 | 0.5 | 34,000 |
5 per 1000 | 2.5 per 1000 | 0.5 | 27,000 |
6 per 1000 | 3 per 1000 | 0.5 | 22,000 |