Table 1.

Outline of risk of bias assessment

Aspect of trial bias assessed	Type of risk of bias in trial and clarification
1. Random sequence generation	Selection bias
2. Allocation concealment	Selection bias
3. Blinding of participants and personnel	Performance bias
4a. Blinding of outcome assessment - subjective outcomes	Detection bias; e.g. depression symptoms measured on a standardized self-report questionnaire
4b. Blinding of outcome assessment - objective outcomes	Detection bias; e.g. depression remission measured by a structured clinical interview
5. Incomplete outcome data	Attrition bias
6. Selective reporting	Reporting bias
7. Other bias	e.g. when bias may seriously alter the results, such as improper adjustment for baseline imbalances or funding bias