The Quality Improvement for Depression Collaboration: General analytic strategies for a coordinated study of quality improvement in depression care

It is difficult to evaluate the promise of primary care quality-improvement interventions for depression because published studies have evaluated diverse interventions by using different research designs in dissimilar populations. Preplanned meta-analysis provides an alternative to derive more precise and generalizable estimates of intervention effects; however, this approach requires the resolution of analytic challenges resulting from design differences that threaten internal and external validity. This paper describes the four-project Quality Improvement for Depression (QID) collaboration specifically designed for preplanned meta-analysis of intervention effects on outcomes. This paper summarizes the interventions the four projects tested, characterizes commonalities and heterogeneity in the research designs used to evaluate these interventions, and discusses the implications of this heterogeneity for preplanned meta-analysis.