Medical Sociology of National Health Insurance Copayment Removal and Facility-Level Delivery Volume in Ghanaian Primary Care: An Interrupted Time-Series Estimation of Financial-Barrier Exposure and Service Mix

Ghana's National Health Insurance Scheme has repeatedly adjusted copayment rules at primary care facilities, yet the sociological question of how financial-barrier exposure shapes facility-level delivery volume and service mix remains under-theorised. The framework specifies how facility-level monthly delivery volumes can be decomposed into service-mix categories and modelled with segmented regression, allowing analysts to distinguish level shifts from trend changes at the point of copayment removal. Because no facility-level delivery data are supplied for this run, the paper is framed as methodological and theoretical scholarship: it derives estimable quantities, states identifying assumptions, and specifies the exposure contrasts that a credible evaluation would require. The contribution is a discipline-aware specification that connects medical-sociological theory on financial barriers to the econometric structure of interrupted time-series designs, and that clarifies which sociological claims about copayment removal are identifiable from facility volume data and which are not. The paper concludes that copayment removal should be evaluated as a change in the institutional conditions of care-seeking rather than as a simple price shock, and it identifies the data infrastructure Ghanaian primary care would need to support that evaluation.