Data, concepts and methods for large-n comparative climate change adaptation policy research: A systematic literature review

Climate change adaptation research is dominated by in‐depth, qualitative, single‐ or small‐n case studies that have resulted in rich and in‐depth understanding on adaptation processes and decision making in specific locations. Recently, the number of comparative adaptation policy cases has increased, focusing on examining, describing, and/or explaining how countries, regions, and vulnerable groups are adapting across a larger sample of contexts and over time. There are, however, critical empirical, conceptual and methodological choices and challenges for comparative adaptation research. This article systematically captures and assesses the current state of larger‐n (n ≥ 20 cases) comparative adaptation policy literature. We systematically analyze 72 peer‐reviewed articles to identify the key choices and challenges authors face when conducting their research. We find among others that almost all studies use nonprobability sampling methods, few existing comparative adaptation datasets exist, most studies use easy accessible data which might not be most appropriate for the research question, many struggle to disentangle rhetoric from reality in adaptation, and very few studies engage in critical reflection of their conceptual, data and methodological choices and the implications for their findings. We conclude that efforts to increase data availability and use of more rigorous methodologies are necessary to advance comparative adaptation research.