Risk of bias in individual studies

All publications selected for inclusion in the systematic literature review will undergo rigorous critical appraisal by one independent reviewer (with prior quality assessment experience [56]) using the appropriate tool from The Joanna Briggs Institute (JBI) [57, 58, 59]. The suite of JBI tools were deemed most appropriate for this systematic literature review, due to the broad range of tools available to assess various study designs/ evidence types (both quantitative and qualitative – ensuring consistency in our assessment), and where appropriate, these tools have been recently updated in order to align with current methodological developments/ nomenclature in this field, including the concept of “risk of bias” (i.e., potential for systematic error) rather than “critical appraisal” to interrogate quantitative evidence. These assessment tools are recommended and deemed acceptable [60]. Information on study strengths/limitations (as reported in the literature) will also be captured in the data extraction table.

For the purposes of our research question, a formal assessment of publication bias (e.g. assessed by funnel plots and Egger’s test), as would be done for a meta-analysis, is not appropriate. However, a narrative consideration of publication bias will be provided in the final results report. For those studies evaluating intervention effectiveness, acceptability or usability, outcome reporting bias will be assessed through comparison of reported outcomes in the results, versus those listed in the methods and/or study protocol, if available [51]. Language bias, a subtype of reporting bias, will also be discussed in the results, including a summary of the number of studies excluded on this basis (i.e. study not published in English), and the potential implications/ consequences of exclusion [61].