The Medicaid and CHIP Payment and Access Commission (MACPAC) was established in the Children's Health Insurance Program Reauthorization Act of 2009, and its charge was later revised in the Patient Protection and Affordable Care Act of 2010. The Commission is a non-partisan, federal, analytic resource for the Congress on Medicaid and CHIP. MACPAC is the first federal agency charged with providing policy and data analysis to the Congress on Medicaid and CHIP, and for making recommendations to the Congress and the Secretary of the U.S. Department of Health and Human Services on a wide range of issues affecting these programs. The Commission conducts independent policy analysis and health services research on key Medicaid and CHIP topics, including but not limited to: eligibility, enrollment, and benefits; payment; access to care; quality of care; interactions of Medicaid and CHIP with Medicare and the health care system generally; and data development to support policy analysis and program accountability. The Commission's reports provide the Congress with a better understanding of the Medicaid and CHIP programs, their roles in the U.S. health care system, and the key policy and data issues outlined in the Commission's statutory charge. In this report, the Commission examines several issues including Medicaid and CHIP eligibility and coverage for maternity services, the newly implemented increase in physician payment for primary care services, access to care for non-elderly persons with disabilities, the availability of Medicaid and CHIP data that can be used for oversight and program monitoring, and improving the effectiveness of program integrity activities. As purchasers of maternity services, Medicaid and CHIP paid for 1.8 million births in 2010, roughly half of all births in many states. States and the federal government have an interest in maximizing positive birth outcomes for all families, particularly those financed with taxpayer dollars. This chapter explores Medicaid and CHIP eligibility and coverage for these services, including enrollment and spending information and also highlights provisions of the ACA that affect eligibility for maternity services in Medicaid, CHIP, and health insurance exchanges. The chapter on Medicaid primary care physician payment focuses on a specific provision of the ACA that became effective in January 2013: increasing Medicaid fees to Medicare payment levels for primary care services provided by primary care physicians. The provision is effective for 2013 and 2014 with the federal government paying 100% of the costs of the difference in fees. To better understand how the provision is being implemented by state Medicaid programs and its impact on beneficiary access and provider participation, we examined the relevant research literature and conducted interviews with states, providers, and other key stakeholders. The feedback received highlights the challenges of implementing this provision and the need for broader investigation into various options to address access gaps in Medicaid. In this report, the Commission builds on previous analyses related to persons with disabilities. Medicaid is an important source of coverage for these individuals, providing services not typically covered by Medicare or private insurers. This report includes a review on access to care for non-elderly adults with disabilities, highlights gaps in existing research, and suggests areas for additional research and analysis. It also focuses on the importance of having accurate, timely, and nationally comparable data on Medicaid and CHIP in order to answer key policy questions that affect enrollees, states, the federal government, health care providers, and others-and in ensuring accountability for taxpayer dollars. This chapter updates the Congress on progress that has been made in improving federal administrative data and identifies areas where additional improvements would benefit policymaking at the federal lev