Risk of bias

Assessing the risk of bias in primary research involves evaluating of individual studies to understand their methodological limitations and potential for generating biased results. This process acknowledges that the reliability of primary studies can substantially vary. The outcome of a risk of bias assessment informs the degree of confidence that can be placed in the inferences drawn from a study. Risk of bias should be assessed using a standardised and validated tool that is appropriate for the respective study design. For example, a tool designed to assess bias in randomised controlled trials would not be suitable for evaluating the risk of bias in an observational cohort study.