Overalignment in Frontier LLMs: An Empirical Study of Sycophantic Behaviour in Healthcare

Fuente: arXiv
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Main Authors: Christophe, Clément, Abdul, Wadood Mohammed, Munjal, Prateek, Raha, Tathagata, Rajan, Ronnie, Kanithi, Praveenkumar
Format: Preprint
Published: 2026
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_version_ 1866911399338311680
author Christophe, Clément
Abdul, Wadood Mohammed
Munjal, Prateek
Raha, Tathagata
Rajan, Ronnie
Kanithi, Praveenkumar
author_facet Christophe, Clément
Abdul, Wadood Mohammed
Munjal, Prateek
Raha, Tathagata
Rajan, Ronnie
Kanithi, Praveenkumar
contents As LLMs are increasingly integrated into clinical workflows, their tendency for sycophancy, prioritizing user agreement over factual accuracy, poses significant risks to patient safety. While existing evaluations often rely on subjective datasets, we introduce a robust framework grounded in medical MCQA with verifiable ground truths. We propose the Adjusted Sycophancy Score, a novel metric that isolates alignment bias by accounting for stochastic model instability, or "confusability". Through an extensive scaling analysis of the Qwen-3 and Llama-3 families, we identify a clear scaling trajectory for resilience. Furthermore, we reveal a counter-intuitive vulnerability in reasoning-optimized "Thinking" models: while they demonstrate high vanilla accuracy, their internal reasoning traces frequently rationalize incorrect user suggestions under authoritative pressure. Our results across frontier models suggest that benchmark performance is not a proxy for clinical reliability, and that simplified reasoning structures may offer superior robustness against expert-driven sycophancy.
format Preprint
id arxiv_https___arxiv_org_abs_2601_18334
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Overalignment in Frontier LLMs: An Empirical Study of Sycophantic Behaviour in Healthcare
Christophe, Clément
Abdul, Wadood Mohammed
Munjal, Prateek
Raha, Tathagata
Rajan, Ronnie
Kanithi, Praveenkumar
Computation and Language
As LLMs are increasingly integrated into clinical workflows, their tendency for sycophancy, prioritizing user agreement over factual accuracy, poses significant risks to patient safety. While existing evaluations often rely on subjective datasets, we introduce a robust framework grounded in medical MCQA with verifiable ground truths. We propose the Adjusted Sycophancy Score, a novel metric that isolates alignment bias by accounting for stochastic model instability, or "confusability". Through an extensive scaling analysis of the Qwen-3 and Llama-3 families, we identify a clear scaling trajectory for resilience. Furthermore, we reveal a counter-intuitive vulnerability in reasoning-optimized "Thinking" models: while they demonstrate high vanilla accuracy, their internal reasoning traces frequently rationalize incorrect user suggestions under authoritative pressure. Our results across frontier models suggest that benchmark performance is not a proxy for clinical reliability, and that simplified reasoning structures may offer superior robustness against expert-driven sycophancy.
title Overalignment in Frontier LLMs: An Empirical Study of Sycophantic Behaviour in Healthcare
topic Computation and Language
url https://arxiv.org/abs/2601.18334