Towards Fairer Health Recommendations: finding informative unbiased samples via Word Sense Disambiguation

TL;DR

This paper investigates bias detection in medical NLP data, proposing the use of Word Sense Disambiguation to improve dataset quality, and evaluates various models showing fine-tuned BERTs outperform LLMs in bias detection tasks.

Contribution

It introduces a novel application of Word Sense Disambiguation to refine bias detection datasets in medical NLP and compares model performances for this task.

Findings

LLMs are unsuitable for bias detection in medical texts.

Fine-tuned BERT models perform well across metrics.

WSD improves dataset quality by removing irrelevant sentences.

Abstract

There have been growing concerns around high-stake applications that rely on models trained with biased data, which consequently produce biased predictions, often harming the most vulnerable. In particular, biased medical data could cause health-related applications and recommender systems to create outputs that jeopardize patient care and widen disparities in health outcomes. A recent framework titled Fairness via AI posits that, instead of attempting to correct model biases, researchers must focus on their root causes by using AI to debias data. Inspired by this framework, we tackle bias detection in medical curricula using NLP models, including LLMs, and evaluate them on a gold standard dataset containing 4,105 excerpts annotated by medical experts for bias from a large corpus. We build on previous work by coauthors which augments the set of negative samples with non-annotated text containing social identifier terms. However, some of these terms, especially those related to race and ethnicity, can carry different meanings (e.g., "white matter of spinal cord"). To address this issue, we propose the use of Word Sense Disambiguation models to refine dataset quality by removing irrelevant sentences. We then evaluate fine-tuned variations of BERT models as well as GPT models with zero- and few-shot prompting. We found LLMs, considered SOTA on many NLP tasks, unsuitable for bias detection, while fine-tuned BERT models generally perform well across all evaluated metrics.