A comparative analysis, enhancement and evaluation of text anonymization with pre-trained Large Language Models

Identifier:  imarina:9465606

Handle: https://hdl.handle.net/20.500.11797/imarina9465606

Authors:  Manzanares-Salor, Benet; Sanchez, David

Abstract:
Large Language Models (LLMs) have gained prominence for their remarkable proficiency across various natural language processing tasks. Recent studies have suggested their potential to outperform current text anonymization methods, although an objective evaluation is needed to validate these claims. To address this issue, this work introduces a comprehensive evaluation framework that automatically assesses both privacy protection and utility preservation without relying on manually curated ground-truth data. Moreover, we conduct an in-depth analysis of the LLM-based text anonymization methods proposed so far. Building on the strengths and limitations we found, we propose a novel method to enhance anonymization quality. We also report extensive experimental comparisons between LLM-based approaches and a variety of previous techniques, including those based on named entity recognition (NER), and those more oriented towards privacy-preserving data publishing (PPDP). The results show that LLM-based approaches effectively outperform traditional methods in terms of privacy and utility. Furthermore, we benchmark against manual anonymization, which performed poorly, thus highlighting the limitations of using them as evaluation ground truth. Notably, our LLM-based method stood out by achieving the best privacy protection, and the best privacy-utility trade-off.