UnitedHealth's nH Predict algorithm allegedly drove wrongful denials of elderly care
A class action alleges UnitedHealth used an algorithm called nH Predict to cut off post-acute care for elderly Medicare Advantage patients in bad faith, despite knowing it was wrong: more than 90% of its denials were reversed on appeal. A federal judge allowed core claims to proceed in 2025.
Over 90% of the algorithm's denials were reversed on appeal, the lawsuit alleges, yet it was still used to cut off care.
Key facts
- What
- A class action alleges UnitedHealth used an algorithm called nH Predict to cut off post-acute care for elderly Medicare Advantage patients in bad faith, despite knowing it was wrong: more than 90% of its denials were reversed on appeal.
- Incident date
- Nov 14, 2023
- Who
- UnitedHealth Group
- Failure mode
- Policy Violation
- AI surface
- Agentic Workflow
- Severity
- Catastrophic
What happened
A 2023 class action alleges UnitedHealth deployed nH Predict, an algorithm with a roughly 90% error rate on appeal, to prematurely deny post-acute care to elderly patients, and pressured staff to keep stays within 1% of the algorithm's prediction. In February 2025 a Minnesota federal judge allowed breach-of-contract and good-faith claims to proceed.
What broke inside the model
- 01 · TriggerA prompt pushes against a deployment boundary.
- 02 · Model stepThe model produces the disallowed output.
- 03 · Control gapNo enforcement blocks it at generation time.
- 04 · FailureThe output crosses the policy line.
- 05 · ConsequenceA limit the business set is breached in public.
The output crosses a policy boundary the deployment had defined.
The system produced an output or action that broke a stated company policy or a regulation that applied to the deployment. The model optimized for a plausible response, not for the constraint, and no enforcement layer checked the output against the policy before it took effect.
What it cost
Class action; alleged denial of medically necessary care to elderly patients
Sources
Cite this entry
https://failureindex.ai/failures/unitedhealth-nh-predict-algorithmAI Failure Index. "UnitedHealth's nH Predict algorithm allegedly drove wrongful denials of elderly care" (FI-0037). Realm Labs. https://failureindex.ai/failures/unitedhealth-nh-predict-algorithm (indexed Jun 3, 2026).Data fields CC-BY 4.0, prose citation permitted. Incident ID FI-0037. Full dataset at /data.
Note from Realm Labs, the Index steward
How Realm would have caught this
- Prism
- OmniGuard
Realm compares what the model is about to output or do against the policy that governs the deployment, in real time, and can deny or redact the action before it takes effect, which is the gap an after-the-fact review never closes in time.