Re-evaluating heterogeneity in evidence synthesis

Evidence Synthesis, in the form of systematic review and meta-analysis, has seen an enormous increase in recent years, across many different scientific disciplines. However, philosophers have paid comparatively little attention to evidence synthesis, while the majority of analyses are predominantly negative and focus primarily on the use of meta-analysis in medicine. One of the main critiques of evidence synthesis is the existence and treatment of heterogeneity between primary studies. The aim of this paper is to re-examine heterogeneity in evidence synthesis, including perspectives from evolutionary biology, ecology and conservation. I argue that while some of the critiques of heterogeneity remain valid, there are contexts where heterogeneity is much less problematic than has been portrayed and can even be useful, as analysing it can provide valuable information, which ultimately increases the quality of the synthesis.