Integrating epidemiologic analysis and mixed methods design to advance place-based community health research: An explanatory sequential framework using extreme case selection.

BACKGROUND: Epidemiologic analyses are central to identifying geographic variation in health outcomes, yet they often provide limited insight into the contextual, social, and organizational mechanisms that produce these patterns. Mixed methods research offers a structured approach for extending population-level surveillance by integrating qualitative inquiry that is sensitive to place and context.

METHODS: This paper presents a methodological framework that embeds epidemiologic analysis within an explanatory sequential mixed methods design guided by extreme case selection. County-level colorectal cancer (CRC) mortality-to-incidence ratios (MIRs) are used as an illustrative epidemiologic indicator to identify high- and low-performing places. These quantitative contrasts inform purposive selection of community sites for qualitative inquiry, including focus groups with community members and interviews with healthcare providers.

ILLUSTRATIVE APPLICATION: Rather than presenting empirical results, this paper demonstrates how epidemiologic stratification can be used to structure qualitative data collection and integration in ways that enhance interpretive depth and attention to place.

CONCLUSION: Coupling epidemiologic surveillance with explanatory sequential mixed methods design, and extreme case sampling, strengthens the capacity of place-based health research to move from description to explanation. This framework offers a replicable methodological approach for researchers seeking to translate population health data into contextually grounded hypotheses and intervention design without treating qualitative and quantitative methods as analytically separate.