Methods. The methods of this review were based on recommendations for systematic review for evidence-based clinical practice (Higgins and Green 2006; Khan et al. 2001), with adaptations for the review's broader health systems and policy-related questions (e.g., Adair et al. 2003; Lavis et al. 2004; Wilczynski et al. 2004).Before initiating the search, draft research questions were validated ....