Risk of bias and quality assessment

All included (quantitative, qualitative, and mixed methods) studies will be critically appraised for methodological quality using the Mixed Methods Appraisal Tool (MMAT) [51, 52]. The MMAT provides comprehensive guidelines and simplicity for summarizing overall quality across a range of study designs (e.g., quantitative, qualitative or mixed methods). Each study will be assigned an overall quality score, using asterisks representing the quality appraisal of each study. For qualitative and quantitative studies, there are four specific criteria and the scores will vary from 25% (*) when one criterion is met to 100% (****) when all four criteria are met [51]. For mixed-methods studies, there are three criteria, and the scores vary from 50% (**) when one criterion is met to 100% (****) when all three criteria are met [51]. Concomitant appraisal of qualitative and quantitative aspects of each mixed-methods study is required in the MMAT tool, with the overall score not exceeding the lowest component score [51]. Two reviewers (MC, DC) will independently assess the quality of studies, and disagreement will be resolved through consensus, and discussion with a third reviewer (CB). We will construct a risk of bias table to present the results. We will also conduct a sensitivity analysis where the studies perceived to be of lower quality (lower MMAT scores) will be compared with higher quality (higher MMAT score) [51]. Studies will not be excluded on quality grounds, but lower quality studies will be reviewed to see if they alter the outcome of the synthesis.