Table 1 Risk of bias assessment tool
Risk of bias | Rationale | Relevant points and relative scoring (1 = low risk; 2 = medium risk; 3 = high risk)a |
|---|---|---|
Funding bias | Potential tendency for the study to support the interests of the sponsor | What was the role of the evaluated funding body in the financing of the study? 1. The study or its author(s) did not receive funding from the body they evaluate 2. The study or its author(s) were partly funded by the body they evaluate 3. The study or author(s) was funded exclusively by the body they evaluate |
Selection bias | The selected samples (including individuals, groups or data) are not representative of the population studied | Is the selected sample likely to be representative of the population being reviewed? 1. Very likely 2. Somewhat likely 3. Not likely |
Reporting bias | The reported outcomes are inaccurate or inappropriate | Are all aspects of the study (including aims, methods and results) clearly described and reported? Is there a balance between reported data/opinions and critical analysis or are these consistently more favourable of the outcome/funding in analysis? 1. All aspects of the study clearly described with supporting evidence 2. Some aspects/evidence of the study are not clear 3. Several aspects/evidence of the study are missing with difficult interpretation of the findings |