Language models reflect clinical evidence but fail to adapt it to patients
- 1Division of AI, Department of Emergency Medicine, Mass General Brigham
Abstract
BackgroundClinical language models must use evidence to produce the number and action required by a particular case. Whether numerical knowledge reliably becomes a correct clinical response is unclear.
MethodsNUMBERS evaluated 16 model configurations on 1,300 questions linked to public clinical evidence. Linked experiments tested prevalence updating, patient-specific estimates and clinical actions. The direct-action experiment compared cutoff recall plus action selection with a supplied complete rule across 50 rules, five models and 7,500 calls.
ResultsAmong diagnostic estimates outside the source-result tolerance, 77.1% remained within the evidences central 80% predictive range. Models updated prevalence-dependent quantities correctly in 78.5% of comparisons with inputs and a calculation request, versus 33.7% with clinical wording. Supplying inputs and requesting calculation raised patient-level near-target answers from 29.7% to 78.8% across 2,340 pairs. Models selected an incorrect action despite stating a cutoff that implied the correct action in 413 of 3,750 recall-arm calls (11.01%; 95% confidence interval, 8.93 to 13.17). Supplying the complete rule raised action accuracy from 85.63% to 99.41%, an improvement of 13.79 percentage points (95% confidence interval, 11.65 to 15.95).
ConclusionsModels often produced evidence-consistent numbers but failed to adapt them to a case or act consistently with their own stated cutoff. Explicit inputs, calculations and complete rules substantially improved performance in controlled prompts.
FundingNational Academy of Medicine, Agreement No. 2026A008797
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BibTeX
@misc{he2026language,
title = {{Language models reflect clinical evidence but fail to adapt it to patients}},
author = {S. He and J. W. Joseph and P. Safari and A. Goff and P. J. Slusarz and A. Mohamed and S. Lord and J. N. Goldstein and A. S. Raja},
howpublished = {medRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.14.26363047},
url = {https://www.medrxiv.org/content/10.64898/2026.09.14.26363047v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Language models reflect clinical evidence but fail to adapt it to patients
AU - S. He
AU - J. W. Joseph
AU - P. Safari
AU - A. Goff
AU - P. J. Slusarz
AU - A. Mohamed
AU - S. Lord
AU - J. N. Goldstein
AU - A. S. Raja
PY - 2026
DA - 2026/09/14
PB - medRxiv
DO - 10.64898/2026.09.14.26363047
UR - https://www.medrxiv.org/content/10.64898/2026.09.14.26363047v1
AB - BackgroundClinical language models must use evidence to produce the number and action required by a particular case. Whether numerical knowledge reliably becomes a correct clinical response is unclear. MethodsNUMBERS evaluated 16 model configurations on 1,300 questions linked to public clinical evidence. Linked experiments tested prevalence updating, patient-specific estimates and clinical actions. The direct-action experiment compared cutoff recall plus action selection with a supplied complete rule across 50 rules, five models and 7,500 calls. ResultsAmong diagnostic estimates outside the source-result tolerance, 77.1% remained within the evidences central 80% predictive range. Models updated prevalence-dependent quantities correctly in 78.5% of comparisons with inputs and a calculation request, versus 33.7% with clinical wording. Supplying inputs and requesting calculation raised patient-level near-target answers from 29.7% to 78.8% across 2,340 pairs. Models selected an incorrect action despite stating a cutoff that implied the correct action in 413 of 3,750 recall-arm calls (11.01%; 95% confidence interval, 8.93 to 13.17). Supplying the complete rule raised action accuracy from 85.63% to 99.41%, an improvement of 13.79 percentage points (95% confidence interval, 11.65 to 15.95). ConclusionsModels often produced evidence-consistent numbers but failed to adapt them to a case or act consistently with their own stated cutoff. Explicit inputs, calculations and complete rules substantially improved performance in controlled prompts. FundingNational Academy of Medicine, Agreement No. 2026A008797
ER -