Mixed methods research is well-suited to grapple with questions of what counts as valid knowledge across different contexts and perspectives. This article introduces Weight of Evidence as a transformative procedure for stakeholders to interpret, expand on and prioritize evidence from evidence syntheses, with a focus on engaging populations historically excluded from planning and decision making. This article presents the procedure’s five steps using pilot data on perinatal care of immigrant women in Canada, engaging family physicians and birth companions. Fuzzy cognitive mapping offers an accessible and systematic way to generate priors to update published literature with stakeholder priorities. Weight of Evidence is a transparent procedure to broaden what counts as expertise, contributing to a more comprehensive, context-specific, and actionable understanding.