Boya Zhang successfully defends her PhD thesis
Congratulations to Dr. Boya Zhang, who successfully defended her PhD thesis, Your Health Questions Answered by Reliable Language Models, on 2 September 2026 at Campus Biotech in Geneva. Boya was a candidate for the Doctorat ès sciences en Sciences de la vie of the Faculties of Medicine and Science of the University of Geneva, with a specialisation in Genomics and Digital Health, and carried out her research within the DS4DH group under the supervision of Prof. Douglas Teodoro at the Department of Radiology and Medical Informatics. Her thesis addresses a vital challenge in modern healthcare AI: assessing the quality of health information and mitigating hallucination in large language models. Along the way, she developed methods and open benchmarks that advance how language models retrieve health information, verify clinical claims, and reason through conflicting biomedical evidence:
- Multi-dimensional information retrieval: a retrieval approach that ranks online health information not only by query-document relevance, but also by its usefulness, supportiveness and credibility, showing that combining these information quality dimensions increases the helpfulness of health search results (JMIR AI, 2024).
- CliniFact: a scientific claim verification benchmark derived from hypothesis testing results in clinical research, comprising 1,970 claim-evidence instances from 992 clinical trials linked to 1,540 publications, designed to evaluate how well language models assess clinical research claims (Scientific Data, 2025).
- HealthContradict: an expert-verified benchmark of 920 instances pairing health questions with contradictory documents, which quantifies how language models behave under biomedical knowledge conflicts and whether they can exploit correct context while resisting incorrect context (npj Digital Medicine, 2025).
Beyond her scientific contributions, Boya's sharp intellect, boundless energy and generous team spirit have deeply enriched our lab, and supervising her has been a pleasure both scientifically and personally. The whole DS4DH team celebrated this milestone together with her and looks forward to the remarkable trajectory ahead. Congratulations, Dr. Zhang!