Table 2 power to detect a specified difference for a fixed sample size
From: CORONIS - International study of caesarean section surgical techniques: the follow-up study
Outcome examples | Event rate in 1st group e.g. single layer closure | Event rate in 2nd group e.g. double layer closure | Absolute risk difference | Power available to detect this difference |
|---|---|---|---|---|
For all women (number estimated to be ~7,400) | ||||
Involuntary infertility | 3% | 4.5% | 1.5% | 92% |
Subsequent pregnancy | 48% | 44% | 4% | 93% |
Dyspareunia | 19% | 16% | 3% | 92% |
For women who have a subsequent pregnancy (number estimated to be ~5,900) | ||||
Uterine rupture or dehiscence | 4% | 5.9% | 1.9% | 92% |
Preterm birth | 10% | 7.5% | 2.5% | 93% |