Clinically Grounded Privacy Evaluation of Medical LMs

Sasha Ronaghi, Sana Tonekaboni, Lena Stempfle, Vivian Utti, Jordan Li Cahoon, Nathaniel Hendrix, Ayin Vala, Marzyeh Ghassemi, Emily Alsentzer


Abstract
Medical language models (LMs) can memorize and reproduce protected health information, but privacy evaluations often focus on recovery of training text rather than disclosure under realistic threat models. We introduce a clinically grounded framework that evaluates leakage along a graded axis of adversarial access, ranging from publicly inferable demographics to leaked note fragments. At each tier, we measure verbatim memorization of patient-specific text and semantic leakage of sensitive diagnoses. Applying the framework to an LM continually pretrained on 378k clinical notes, we find that routine encounter metadata (i.e., name, date of birth, visit date, provider name, and practice location) elicits high rates of verbatim memorization across a patient’s timeline and sensitive-diagnosis recovery (AUROC 0.91 for abortion, 0.82 for HIV). At the same time, exact-match memorization can overstate disclosure: 36% of memorized tokens reflect templated documentation. Our work highlights the risks of training on longitudinal clinical data and provides a practical, reusable framework for contextual privacy evaluation of medical LMs.
Anthology ID:
2026.emnlp-main.2388
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
54266–54295
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2388/
DOI:
Bibkey:
Cite (ACL):
Sasha Ronaghi, Sana Tonekaboni, Lena Stempfle, Vivian Utti, Jordan Li Cahoon, Nathaniel Hendrix, Ayin Vala, Marzyeh Ghassemi, and Emily Alsentzer. 2026. Clinically Grounded Privacy Evaluation of Medical LMs. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 54266–54295, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Clinically Grounded Privacy Evaluation of Medical LMs (Ronaghi et al., EMNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.emnlp-main.2388.pdf