The goal of this project is to inform Medicaid policymakers and health plan leaders to ensure adequate primary care access for growing and diverse Medicaid populations, particularly highly complex patients. Findings will also inform states on how local primary care markets respond to changes in Medicaid coverage and provider payment rates. The researchers will explore the supply side of the health sector in New Jersey and whether physicians are able to meet the growing demand for services generated by the Medicaid expansion. Specifically, they will address the following: (1) how has the local supply of primary care services responded to Medicaid expansion; (2) how do supply factors and prices paid to local primary care providers affect patient-level access to primary care; and (3) how does the answer to question two vary by patient subgroups, including those with a history of homelessness or serious mental illness (SMI) and newly enrolled versus previously enrolled. Deliverables will include a project work plan and final narrative and financial reports. The grantee will also produce paper(s) suitable for publication and present findings at national research meetings and to other stakeholder audiences as appropriate, including policymakers at the federal, state, and local levels, as part of the deliverables for this grant.