Rural-urban comparisons of area-based socioeconomic disadvantage and vulnerability indices.

Background: Policymakers and health systems increasingly rely on area-based socioeconomic disadvantage indices to inform health policy and resource allocation. However, the extent to which indices score the same areas differently across the rural-urban continuum remains poorly understood. Methods: We compared 5 nationwide US indices (2022 versions) at the census tract level across 4 rural-urban designations using correlations, reliability testing, and decile score distributions. For the most discordant pair, the Neighborhood Atlas Area Deprivation Index (NA-ADI) and the Social Vulnerability Index (SVI), we used ridge regression and dominance analysis to identify specific items driving index disagreement. Results: Disadvantage indices are not interchangeable. The NA-ADI's unstandardized items demonstrated rural-urban and demographic biases. In metropolitan areas, NA-ADI's overweighted housing cost and income items masked vulnerability among housing cost-burdened, predominantly urban minority populations, classifying these tracts as low deprivation. Conversely, in nonurban areas, NA-ADI inflated deprivation scores in predominantly White tracts, with relatively lower proportions of disadvantage indicators, due to inherently lower housing costs. Conclusion: The NA-ADI's lack of item standardization risks exacerbating disparities that disadvantage indices aim to alleviate. Transitioning to more methodologically rigorous, transparent indices and developing context-specific rural metrics are urgent imperatives for effective, efficient resource allocation and to address health disparities.