This article presents an innovative evaluation design which was used to evaluate the Swiss Environmental Impact Assessment. The design is new in that it amalgamates the realistic approach to evaluation with the method of Qualitative Comparative Analysis (QCA), the two of which are conspicuously similar. They share a complex view of causality, a generative perspective, a theory-driven approach to empirical observation and a limited claim to generalization. These conceptual parallels, as derived from the literature, are described in the first section, after a short introduction to realistic evaluation and the method of QCA. The following empirical section exemplifies their joint application and tackles the problems encountered. Based on this experience, the initial theoretical parallels are then reviewed. The article concludes that, under certain conditions, realistic evaluation and QCA provide a powerful tandem to produce empirically well-grounded context-sensitive evidence on policy instruments.