How to do (or not to do) realist evaluations to advance theory, practice, and justice in health systems research.

The realist approach seeks to understand underlying mechanisms that explain how and why complex interventions, programmes, and policies work in specific contexts, making it particularly valuable in health policy and systems research (HPSR). We draw on reflexive practice of realist evaluations from several realist evaluation practitioners and on insights from an organized session at the Eighth Health Systems Research Symposium in Nagasaki, Japan, in 2024, where we engaged a diverse group of practitioners and researchers on how to use realist approaches in HPSR. Examples from our studies, while situated in distinct contexts, highlight common challenges in applying realist methodologies including identifying and refining context-mechanism-outcome configurations. Building on these examples, we illustrate how realist evaluations, if conducted rigorously and with the purpose of advancing justice in health systems, could do so through exposing structural barriers to health justice, amplifying local voices and fostering epistemic justice in knowledge production.