UnitedHealth’s AI algorithm allegedly carried a 90% error rate for post-acute care denials. A Senate investigation found denial rates more than doubled after deployment.
The nH Predict algorithm, developed by subsidiary naviHealth (now Optum), allegedly overrode physician determinations and denied medically necessary post-acute care. Nine of ten appealed denials were ultimately reversed. A 2024 Senate investigation found UnitedHealth’s denial rate for post-acute care more than doubled after deploying the tool. In March 2026, a federal judge ordered broad discovery on the algorithm’s implementation.
rate on appeal
after AI deployment
by federal judge
An AI that overrides physicians and is wrong 90% of the time on appeal is not a decision-support tool. It is an automated denial engine. AVAAS harm-of-inaction scoring catches exactly this pattern: AI that denies care patients should have received. The Irreversibility Index would have flagged these decisions as maximally irreversible before the algorithm reached production.
This entry is one of 37 documented cases in the AVAAS evidence ledger, a public record of AI and automated-system failures with a verified source on every entry.
Every case here reached a person.
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