Assessing 'what works' in international development: Meta-analysis for sophisticated dummies

Many studies of development interventions are individually unable to provide convincing conclusions because of low statistical significance, small size, limited geographical purview and so forth. Systematic reviews and meta-analysis are forms of research synthesis that combine studies of adequate methodological quality to produce more convincing conclusions. In the social sciences, study designs, types of analysis and methodological quality vary tremendously. Combining these studies for meta-analysis entails more demanding risk of bias assessments to ensure that only studies with largely appropriate methodological characteristics are included, and sensitivity analysis should be performed. In this article, we discuss assessing risk of bias and meta-analysis using such diverse studies.