A risk of bias assessment can be completed using a variety of scales or checklists, such as the Cochrane Collaboration’s tool for assessing risk of bias. Two reviewers should conduct a risk of bias tool independently and check agreement before starting with level one and two screening. The individual components for each risk-of-bias item should be reported for each study. Simply reporting a score from an assessment scale is not as helpful to the end user because there is insufficient detail to understand the sources of bias. Excluding studies from a review based on their risk of bias is not advisable. Rather, the impact of this potential bias can be addressed through sensitivity analyses, which explore whether results of the review are robust to differences across the studies.
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