Quantifying and Mitigating Premature Closure in Frontier LLMs
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Abstract (arXiv)
Premature closure, or committing to a conclusion before sufficient information is available, is a recognized contributor to diagnostic error but remains underexamined in large language models (LLMs). We define LLM premature closure as inappropriate commitment under uncertainty: providing an answer, recommendation, or clinical guidance when the safer response would be clarification, abstention, escalation, or refusal. We evaluated five frontier LLMs across structured and open-ended medical tasks. In MedQA (n = 500) and AfriMed-QA (n = 490) questions where the correct choice had been removed, models still selected an answer at high rates, with baseline false-action rates of 55-81% and 53-82%, respectively. In open-ended evaluation, models gave inappropriate answers on an average of 30% of 861 HealthBench questions and 78% of 191 physician-authored adversarial queries. Safety-oriented prompting reduced premature closure across models, but residual failure persisted, highlighting the need to evaluate whether medical LLMs know when not to answer.
Key facts. Cited by 4 papers in the map (data through 14 Oct 2026). Builds on 17 of its 36 references that are in the map. First posted on arXiv 14 May 2026.
Builds on
17 of 36 references.
References · 17
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5 more
- 2025Large language models provide unsafe answers to patient-posed medical questionscited by 18
- 2024Prompt engineering paradigms for medical applications: scoping review and recommendations for better practicescited by 14
- 2025Mitigating Over-Refusal in Aligned Large Language Models via Inference-Time Activation Energycited by 5
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- 2025Prompt engineering does not universally improve Large Language Model performance across clinical decision-making taskscited by 1
Built on by
Citing papers per year: 2026: 4.
4 papers.
- 2026InsufficiencyBench: Evaluating LLM legal advice on underspecified user queriescited by 1
- 2026Why Didn't It Check? Unsupported Final Claims and Their Repair in Two Tool-Equipped Language Modelscited by 0
- 2026Can LLMs Value the Right Evidence? Evidence-Value Misalignment in Dynamic Medical Diagnosiscited by 0
- 2026Not Until the Evidence Says So: Teaching LLM Investigators When to Close a Casecited by 0
- 2026Not Until the Evidence Says So: Teaching LLM Investigators When to Close a Case2 Oct 2026
- 2026Can LLMs Value the Right Evidence? Evidence-Value Misalignment in Dynamic Medical Diagnosis28 Sep 2026
- 2026Why Didn't It Check? Unsupported Final Claims and Their Repair in Two Tool-Equipped Language Models27 Aug 2026
- 2026InsufficiencyBench: Evaluating LLM legal advice on underspecified user queries20 Aug 2026