• Managed care architectures, notably HMOs and capitation, emerged as policy instruments to enroll beneficiaries, manage risk, and constrain Medicare/Medicaid costs; studies examine enrollment trends, risk-sharing contracts, and pre-enrollment reimbursements in at-risk plans [4], [5], [7], [20], [18], [12], [19].

• Payment reform and cost containment mechanisms, including prospective payment for hospitals, DRGs, and broader cost projections, are central levers shaping incentives, expenditures, and program design in public programs [10], [3], [11], [8], [19], [1], [13].

• Provider participation, access, and distribution under public programs influence care availability; analyses address physician supply, Medicaid participation by clinicians, pediatric involvement, and dual-eligible contexts [2], [14], [12], [15], [17].

• State policy experimentation and variation in managed care adoption reveal how waivers, reform initiatives, and program design shape HMO uptake, capitation, and service delivery across states [12], [18], [17], [19].

• End-user high-cost populations—end-of-life Medicare use, dual-eligible elderly in the community, and ESRD programs—illustrate how coverage design interacts with utilization and financial protection [1], [15], [13].