The last decades have seen an enormous growth in published research and evaluations, which makes it difficult for a researcher to stay up-to-date in their own field, let alone complement their knowledge with insights from other fields. In this paper we give an elaborate overview of a methodology that aims to tackle this task. It builds on the realist evaluation science approach and combines it with qualitative comparative analysis (QCA), hence its name: the ResQ approach. Central to the approach are generative mechanisms that can be found across fields, domains, sectors and contexts. The approach sets out to synthesize the evidence on the circumstances linked to the triggering of these mechanisms. QCA is used to identify the most relevant conditions, leading to theories around these mechanisms, called 'mechanism concepts'. New studies can test, and refine the mechanism concepts, setting up a continuous cycle of theory-building across disciplines enabling us to learn from other fields, disciplines and contexts in a systematic way.