Dr. Mika Hamer is about to go ghost hunting. With a $100,000 grant from the Robert Johnson Wood Foundation (RWJF), University of Maryland School of Public Health researcher aims to uncover the extent of so-called “shadow networks” in diets Medicare Advantage health insurance.

A “shadow network” describes the difference between the health care providers advertised as in-network for a given insurance plan and the providers who are actually available to provide care to patients enrolled in those plans – meaning that a patient has more options on paper than in reality. In 2024, Medicare Advantage provided health insurance to more than 33 million Americans over age 64, more than half of all Medicare customers nationwide, according to KFF.

We want patients with Medicare Advantage plans to know their real options. By knowing the scale of these shadow networks, why they exist and who they affect most, we will then be able to propose practical policy solutions to help. We already know that access to care and finding doctors to accept new patients is a problem. This study will show exactly where and how many shadow networks exist in Medicare Advantage, and who is most affected by larger shadow networks. »

Dr Mika Hamer, Assistant Professor, SPH Department of Health Policy and Management

Hamer’s research will focus on patient health care access, quality, and equity as it relates to Medicare Advantage plans, and examine nationwide Medicare Advantage enrollment and visit data as well as provider network data from 2017 to 2021. Its funding, RWJF’s Health Data for Action program, has allowed researchers to access health data that would often be prohibitively expensive. Beyond identifying ghost networks, the study will also examine the geographic locations, race, gender, ethnicity, age and other factors of people participating in schemes with ghost networks.

“We are excited to work with Dr. Hamer and the UMD School of Public Health to make valuable data available for this important research on shadow networks in Medicare Advantage.” This study is poised to contribute actionable evidence to advance quality and access to care for Medicare. Benefits for enrollees,” said Megan Collado, senior director of AcademyHealth, the organization that manages the RWJF Health Data for Action program.

This work was supported by a grant (#82516) from the Robert Johnson Wood Foundation. The opinions expressed here do not necessarily reflect those of the Foundation. To request an interview with Dr. Hamer, please contact (email protected).