Research synthesis techniques such as systematic reviews and metaanalyses have become standard methods for aggregating the results from thematically related research in psychology. In this "Hotspots" issue, leading researchers describe state of the art systematic reviews and meta-analyses on topics currently being debated in psychology, meta-analytic replications and extensions of previously published synthesis, and methodological advances in research synthesis methods such as multivariate/multilevel meta-analysis, Bayesian approaches, meta-analysis with mixture models, and study quality appraisal tools. Using the latest research synthesis techniques, leading researchers describe the state of the art in various research fields, test and compare theories, and derive conclusions about the effectiveness of interventions.
