Quantifying eldercare vulnerability in 4-2-1 families and evaluating multilevel policy support across East Asia

Rapid population ageing in East Asia is reshaping family risk, especially in 4-2-1 households where one working-age adult bears layered financial and caregiving burdens for two parents and four grandparents. This study develops a composite Eldercare Vulnerability Index (EVI) that integrates health, economic, and social exposures and links it to a three-tier Policy Support Score (PSS) spanning national, provincial/prefectural, and municipal programmes. Using harmonised 2023 micro-surveys from China, Japan, and South Korea (N=12,437), we estimate country-adjusted effects with Bayesian hierarchical models, validate the index against objective hardship events and caregiver stress, and run counterfactual policy simulations. Median baseline EVI differs across countries and displays heavy-tail heterogeneity within countries. Municipal in-kind services, particularly home-based care hours and daycare vouchers, exert larger marginal reductions in EVI than equivalently valued national cash transfers, with positive complementarities across tiers. Scenario analyses indicate that modest local expansions produce outsized, targetable improvements among high-risk clusters. The framework offers a replicable, policy-sensitive diagnostic to guide multilevel reform in rapidly ageing cities.