Mixed-methods impact evaluation in international development practice: distinguishing between quant-led and qual-led models

Despite being widely endorsed for more than two decades, the practice of mixed-methods impact evaluation (MMIE) remains confusing. This paper suggests that greater clarity can be achieved by distinguishing between quant-led and qual-led models of MMIE. The quant-led model gives most weight to variance-based epistemological approaches to causal attribution but can also incorporate process-theory approaches. The qual-led model relies mainly on a process-theory approach but incorporates quantitative data collection and analysis. After setting out the context, the paper sets out these conceptual distinctions. It then presents an illustrative case study of how the Qualitative Impact Protocol (QuIP) has been utilised within the two models. Third, the paper explores divergent support for the two models. We conclude with reflections on how wider recognition of the distinction between them can improve evaluative practice by deepening our understanding of multiple options for the integration of qualitative and quantitative aspects of impact evaluation. While mainly intended to be of practical relevance to those planning, conducting, and reviewing MMIEs, the paper is also relevant to wider concerns over the political economy of knowledge production and distribution.