UMD researcher aims to uncover “ghost networks” in Medicare Advantage health insurance plans

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

A “ghost network” describes the difference between advertised in-network healthcare providers for a given insurance plan and the providers who are in fact available to deliver care to patients enrolled in those plans – meaning a patient has more options on paper than in reality. In 2024, Medicare Advantage provided health insurance for upwards of 33 million Americans over 64 years old, over half of all Medicare clients in the country, according to KFF. 

We want patients on Medicare Advantage plans to know their true options. By learning how big these ghost networks are, why they exist and who they affect most, we will then be able to offer practical policy solutions to help. We already know that accessing healthcare and finding doctors who are accepting new patients is a problem. This study will pinpoint exactly where and how many ghost networks exist in Medicare Advantage, and who is most affected by larger ghost networks.”

Dr. Mika Hamer, assistant professor, SPH Department of Health Policy and Management

Hamer’s research will focus on patients’ healthcare access, quality and equity with regard to Medicare Advantage plans, and will examine nationwide Medicare Advantage enrollment and visit data and provider network data from 2017 to 2021. Her funding, RWJF’s Health Data for Action program, has enabled researchers access to health data that is often otherwise cost prohibitive. Beyond identifying the ghost networks, the study will also examine geographic locations, race, sex, ethnicity, age and other factors of people participating in plans with ghost networks. 

“We are thrilled to be working with Dr. Hamer and UMD School of Public Health to make valuable data available to this important research around ghost networks in Medicare Advantage. This study is poised to contribute actionable evidence to advance quality and access to care for Medicare Advantage enrollees,” said Megan Collado, senior director at 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 views expressed here do not necessarily reflect the views of the Foundation. To request an interview with Dr. Hamer, please reach out to [email protected].