Uncovering Medicare Advantage Overbilling: A Deep Dive into Data-Driven Journalism
A 2024 investigation by The Wall Street Journal exposed questionable billing practices within Medicare Advantage plans, revealing how insurers may have collected billions of dollars for services not rendered or for conditions patients didn’t have. The series, which was a finalist for the 2025 Pulitzer Prize in investigative reporting, highlights the power of data-driven journalism and the challenges of accessing and analyzing complex healthcare data.
The Unusual Data Access
In the fall of 2022, a team of reporters from The Wall Street Journal took an unconventional approach to investigating suspected overbilling in Medicare Advantage. They requested access to Medicare data from the federal Centers for Medicare & Medicaid Services (CMS), asking the agency to treat the journalists as researchers. “We basically took the unusual step of asking CMS to treat a group of journalists as researchers for purposes of reviewing their massive repository of data,” explained Christopher Weaver, an investigative reporter at the Journal [1].
CMS agreed, granting the team access to 100% of person-level Medicare and Medicaid claims data spanning a 12-year period. This included detailed information on every prescription filled, doctor visit, and hospitalization. The sheer volume of data—billions of medical records—presented a significant challenge. “It was kind of like being the dog that caught up with the car,” Weaver said [1].
The Financial Stakes
The Medicare program cost the federal government $1.12 trillion in 2024. Of that amount, private health insurers operating Medicare Advantage plans were projected to receive between $500 billion and $600 billion [1]. As of this year, 69.7 million seniors are enrolled in Medicare, with 51.1% participating in Medicare Advantage plans [1].
Demonstrating Research Competency
To gain access to the data, the reporting team had to demonstrate to CMS their ability to analyze and utilize the information with the rigor expected of researchers. The data was provided in August 2023 during the Biden administration. Weaver noted uncertainty about whether such access would be as readily granted under a different administration [1].
Key Findings of the Investigation
The Wall Street Journal’s investigation revealed that insurers, including UnitedHealth Group and CVS Health, engaged in questionable billing practices that cost taxpayers billions and potentially jeopardized patient care. Analysis of the data showed hundreds of thousands of questionable diagnoses that generated extra payments, some of which were “outright wrong” [1]. These included diagnoses for potentially deadly illnesses, like AIDS, for which patients received no subsequent care, and conditions patients couldn’t possibly have had.
Specifically, the investigation found instances of insurers adding diagnoses to patient records that were questionable, with some diagnoses being anatomically plausible but not intended for treatment. In one case, a UnitedHealth Group member received a diagnosis of diabetic cataracts despite having no evidence of either diabetes or cataracts [1].
Impact and Recognition
The series, titled “Medicare Inc.,” received significant recognition, including being a finalist for the 2025 Pulitzer Prize in investigative reporting. It also won awards from Investigative Reporters & Editors and the New York Press Club, and was a finalist for the Goldsmith Award from the Shorenstein Center at Harvard University [1]. The reporting was cited more than two dozen times in a January 2026 report by the U.S. Senate Committee on the Judiciary regarding Medicare Advantage overbilling [1].
Challenges and Advice for Future Investigations
Weaver cautioned that replicating this type of investigation without access to similar data would be extremely difficult. “Essentially, it’s a business about manipulating data. How do you expose that without being able to gaze at the numbers?” he asked [1]. The team faced significant technical hurdles, including learning SAS programming and analyzing 40,000 lines of code. They also relied on patient-provided medical records and extensive interviews.
Weaver advised journalists interested in similar work to start with smaller-scale projects, such as analyzing hospital or nursing home claims, to build the necessary skills and competencies.