# Learning from Program Differences between Medicaid and Medicare

> **NIH NIH P01** · HARVARD MEDICAL SCHOOL · 2020 · $309,212

## Abstract

ABSTRACT
Medicare and Medicaid are the largest social health insurance programs in the United States, together
providing health insurance for over 130 million Americans. While the programs share some key attributes, they
also differ in important ways, with the key institutional difference being that states have significant control over
the design of their Medicaid programs while Medicare is managed at the national level. Despite their
importance to the U.S. health care system, there is little rigorous quasi-experimental work studying how the
two programs compare to each other in terms of their effects on health care access, quality, and outcomes for
enrollees. In this project, we will examine the relative effects of these two programs by following adults with
disabilities who are enrolled in Medicaid before age 65 into Medicare at age 65 and beyond—that is, as
disabled adults with only Medicaid switch to become dual-eligibles enrolled in both Medicaid and Medicare.
Adults with disabilities who are dually enrolled in both Medicaid and Medicare before age 65 will serve as the
control group, as they do not experience a transition between programs at age 65. Studying these changes to
dual eligibility will allow us to isolate the average effects of state Medicaid programs on patient care and
outcomes relative to a structurally different Medicare program (e.g., with a wider set of participating providers
than Medicaid), as well as to explore variation in these effects across features of state Medicaid programs. In
Aim 1, we will estimate how enrollees' care and outcomes differ in these two programs. In Aim 2, we will
explore the mechanisms behind the program differences. To do this, we will leverage the fact that there is not
one Medicaid program but 51, with varying levels of provider access and payment. Specifically, we will analyze
how the Medicaid-Medicare transition differs in states with high provider payments (relative to Medicare) vs.
states with low provider payments. We will do the same to compare states that contract out the provision of
Medicaid benefits to private managed care plans vs. states that do not. This will provide new evidence on the
extent to which these two important factors explain overall Medicaid-Medicare differences and will have
implications for program design. In Aim 3, we focus on one specific component of the Medicaid and Medicare
benefit packages: prescription drugs. We will use the introduction of Medicare Part D (which shifted dual-
eligibles from Medicaid drug coverage to Medicare drug coverage) to assess how the drug benefit component
of these two programs differentially affects enrollees' use of drugs and related health outcomes. Here, we will
also leverage variation across state Medicaid programs to explore mechanisms, focusing on variation in state
use of caps on the number of prescriptions beneficiaries can fill and prior authorization requirements. These
analyses will provide critical lessons for the effects o...

## Key facts

- **NIH application ID:** 9937244
- **Project number:** 2P01AG032952-11
- **Recipient organization:** HARVARD MEDICAL SCHOOL
- **Principal Investigator:** Thomas G. McGuire
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $309,212
- **Award type:** 2
- **Project period:** — → —

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9937244

## Citation

> US National Institutes of Health, RePORTER application 9937244, Learning from Program Differences between Medicaid and Medicare (2P01AG032952-11). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9937244. Licensed CC0.

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