Replication Data for: What Do Microinsurance and Medicare Have in Common? The Dual Benefit Principle in Health Insurance

Complete replication materials for the paper "What Do Microinsurance and Medicare Have in Common? The Dual Benefit Principle in Health Insurance" submitted to Social Science & Medicine. THE DUAL BENEFIT PRINCIPLE (DBP) The Dual Benefit Principle posits that sustainable collective institutions must provide BOTH social benefits ("good for us") AND private benefits ("good for me"). When institutions deliver only collective benefits without visible personal gains, support erodes because individuals perceive a zero-sum tradeoff. Conversely, providing only individual benefits is structurally impossible in health insurance: insurance by definition requires risk pooling where the healthy cross-subsidize the sick. Without this collective dimension, there is no insurance—only individual savings. The DBP thus identifies the essential balance: sustainable health financing requires that individuals perceive BOTH protection against personal catastrophic risk AND fair contribution to a system that benefits all participants through pooling of risks, which lowers variance of health expenditure for everyone. The DBP explains why both microinsurance schemes serving poor communities and Medicare serving wealthy nations face similar challenges. KEY FINDINGS SUPPORTING THE DBP Using multilevel models on 70,027 respondents across 21 countries: • Zero-sum thinking (H1): Accepting income-based inequality predicts lower confidence (β = -0.134, p < .001) • Perceived free-riding (H3a): Believing others overuse services predicts lower confidence (β = 0.050, p < .001) • Contested deservingness (H3b): Restrictive access views predict higher confidence, revealing a "welfare chauvinism" pattern • Cross-national consistency: Zero-sum effect negative in ALL 21 countries (100%) • Temporal stability: Effects stable across 2011-2021, spanning COVID-19 pandemic Sample: N = 28,040 (2021); N = 70,027 (pooled) Countries: 21 panel countries ICC: 0.118 (11.8% variance between countries)