Table 3.
Example of assessment of the risk of bias: Quality measures of the randomised controlled trials that failed to fulfil any one of six markers of validity. Adapted from Devereaux et al96
| Trials | Concealment of randomisation | RCT stopped early | Patients blinded | Healthcare providers blinded | Data collectors blinded | Outcome assessors blinded |
|---|---|---|---|---|---|---|
| Liu | No | No | Yes | Yes | Yes | Yes |
| Stone | Yes | No | No | Yes | Yes | Yes |
| Polderman | Yes | Yes | No | No | No | Yes |
| Zaugg | Yes | No | No | No | Yes | Yes |
| Urban | Yes | Yes | No | No, except anaesthesiologists | Yes | Yes |
RCT = randomised controlled trial.