Shaun Khoo
Author directory2026
Small Changes, Big Impact: Demographic Bias in LLM-Based Hiring Through Subtle Sociocultural Markers in Anonymised Resumes
Bryan Chen Zhengyu Tan | Shaun Khoo | Bich Ngoc Doan | Zhengyuan Liu | Nancy F. Chen | Roy Ka-Wei Lee
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Bryan Chen Zhengyu Tan | Shaun Khoo | Bich Ngoc Doan | Zhengyuan Liu | Nancy F. Chen | Roy Ka-Wei Lee
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Large Language Models (LLMs) are increasingly deployed in resume screening pipelines. Although explicit PII (e.g., names) is commonly redacted, resumes typically retain subtle sociocultural markers (languages, co-curricular activities, volunteering, hobbies) that can act as demographic proxies. We introduce a generalisable stress-test framework for hiring fairness instantiated in the Singapore context: 100 neutral job-aligned resumes are augmented into 4100 variants spanning four ethnicities and two genders, differing only in job-irrelevant markers. We evaluate 18 LLMs in two settings: (i) Direct Comparison (1v1) and (ii) Score Shortlist (Top-Score Rates), each with and without rationale prompting. We find that even without explicit identifiers, models recover demographic attributes with high F1 and exhibit systematic disparities, with models favouring markers associated with Chinese and Caucasian males. Ablations show language markers suffice for inferring ethnicity, while hobbies and activities are utilised for gender. Furthermore, prompting for explanations may paradoxically amplify bias. Our findings suggest that seemingly innocuous markers surviving anonymisation can materially skew automated hiring outcomes.
2025
LionGuard: A Contextualized Moderation Classifier to Tackle Localized Unsafe Content
Jessica Foo | Shaun Khoo
Proceedings of the 31st International Conference on Computational Linguistics: Industry Track
Jessica Foo | Shaun Khoo
Proceedings of the 31st International Conference on Computational Linguistics: Industry Track
As large language models (LLMs) become increasingly prevalent in a wide variety of applications, concerns about the safety of their outputs have become more significant. Most efforts at safety-tuning or moderation today take on a predominantly Western-centric view of safety, especially for toxic, hateful, or violent speech. In this paper, we describe LionGuard, a Singapore-contextualized moderation classifier that can serve as guardrails against unsafe LLM usage. When assessed on Singlish data, LionGuard outperforms existing widely-used moderation APIs, which are not finetuned for the Singapore context, by at least 14% (binary) and up to 51% (multi-label). Our work highlights the benefits of localization for moderation classifiers and presents a practical and scalable approach for low-resource languages, particularly English-based creoles.