@inproceedings{alves-etal-2026-leakage,
title = "Leakage-Aware Evaluation of {B}razilian Clinical Notes for {ICU} Mortality Prediction: A Study on the {BRATECA} Dataset",
author = "Alves, Felipe Andr{\'e} Bach and
Boll, Helo{\'i}sa Oss and
Recamonde-Mendoza, Mariana",
editor = "Barbosa, Bryan Khelven da Silva and
Paes, Aline and
Felippo, Ariani Di",
booktitle = "Proceedings of the 17th {B}razilian Symposium in Information and Human Language Technology",
month = oct,
year = "2026",
address = "Cuiab{\'a}, Mato Grosso, Brazil",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.stil-1.2/",
doi = "10.5753/stil.2026.26535",
pages = "14--25",
abstract = "Early prediction of ICU mortality can support clinical decisions, but retrospective notes can contain future-event cues that cause leakage in clinical NLP. We evaluate leakage-aware modeling of Brazilian Portuguese ICU notes for mortality prediction using BRATECA. We compare 24-hour restriction, regex and LLM leakage auditing, neural and TF-IDF representations, and unrestricted-note baselines. In the 24-hour setting, models achieved AUROC 0.78-0.83; unrestricted notes reached around 0.95, indicating outcome-related information in late documentation. Regex found leakage signals in 21.13{\%} of the notes, and the LLM audit identified additional semantic cases. Results highlight the need for temporal control and leakage auditing in clinical NLP."
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<abstract>Early prediction of ICU mortality can support clinical decisions, but retrospective notes can contain future-event cues that cause leakage in clinical NLP. We evaluate leakage-aware modeling of Brazilian Portuguese ICU notes for mortality prediction using BRATECA. We compare 24-hour restriction, regex and LLM leakage auditing, neural and TF-IDF representations, and unrestricted-note baselines. In the 24-hour setting, models achieved AUROC 0.78-0.83; unrestricted notes reached around 0.95, indicating outcome-related information in late documentation. Regex found leakage signals in 21.13% of the notes, and the LLM audit identified additional semantic cases. Results highlight the need for temporal control and leakage auditing in clinical NLP.</abstract>
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%0 Conference Proceedings
%T Leakage-Aware Evaluation of Brazilian Clinical Notes for ICU Mortality Prediction: A Study on the BRATECA Dataset
%A Alves, Felipe André Bach
%A Boll, Heloísa Oss
%A Recamonde-Mendoza, Mariana
%Y Barbosa, Bryan Khelven da Silva
%Y Paes, Aline
%Y Felippo, Ariani Di
%S Proceedings of the 17th Brazilian Symposium in Information and Human Language Technology
%D 2026
%8 October
%I Association for Computational Linguistics
%C Cuiabá, Mato Grosso, Brazil
%F alves-etal-2026-leakage
%X Early prediction of ICU mortality can support clinical decisions, but retrospective notes can contain future-event cues that cause leakage in clinical NLP. We evaluate leakage-aware modeling of Brazilian Portuguese ICU notes for mortality prediction using BRATECA. We compare 24-hour restriction, regex and LLM leakage auditing, neural and TF-IDF representations, and unrestricted-note baselines. In the 24-hour setting, models achieved AUROC 0.78-0.83; unrestricted notes reached around 0.95, indicating outcome-related information in late documentation. Regex found leakage signals in 21.13% of the notes, and the LLM audit identified additional semantic cases. Results highlight the need for temporal control and leakage auditing in clinical NLP.
%R 10.5753/stil.2026.26535
%U https://aclanthology.org/2026.stil-1.2/
%U https://doi.org/10.5753/stil.2026.26535
%P 14-25
Markdown (Informal)
[Leakage-Aware Evaluation of Brazilian Clinical Notes for ICU Mortality Prediction: A Study on the BRATECA Dataset](https://aclanthology.org/2026.stil-1.2/) (Alves et al., STIL 2026)
ACL