OIG OEI-09-16-00410 — Medicare Advantage Appeal Outcomes and Audit Findings

Enrollees and providers appealed only about 1% of denials, even though independent reviewers overturned a large share of the denials that were appealed — evidence that far more people have a winnable appeal than actually file one.ruleOIG (2018): Medicare Advantage Appeal Outcomes and Audit Findings Raise Concerns About Service and Payment Denials — OEI-09-16-00410

The rarity of appealing isn't evidence that most denials are correct — it's evidence that most people who could win an appeal never try. That gap is the entire reason CaseWhy Appeals exists.

A 1% appeal rate means the overwhelming majority of families facing a denial never get to find out whether an independent reviewer would have overturned it. Given how often appeals succeed when they're actually filed, that's a real, quantifiable cost of not appealing — not just a hypothetical one.

This report is one of the earliest federal audits to formally document the pattern CaseWhy Appeals is built around: a real gap between how often a denial is wrong and how often anyone challenges it.

This 2018 report was an early signal of a pattern later OIG reports (2022, 2026) confirmed with more specific, service-level findings — the concern wasn't a one-time anomaly, but a recurring gap between how often Medicare Advantage denials are challenged and how often they turn out to be wrong when they are.

HHS OIG is an independent federal oversight office, not part of CMS or any health plan — its reports are audits of the program, not advocacy for either side, which is part of why the same low-appeal, high-overturn pattern showing up across independent reports years apart carries real weight.

This report is publicly available on HHS OIG's own website and can be cited directly, the same way any other government audit can be referenced in correspondence with a plan.

Cited on the landing page's "appeal paradox" section and the how-it-works page as the reason a denial is worth contesting.