Organizations: Innovation Division, Clalit Research Institute, Clalit Health Services, Ramat-Gan, Israel. · Stein Faculty of Computer and Information Science, Ben Gurion University of the Negev, Be’er Sheva, Israel. · Department of Family Medicine, Clalit Health Services, Tel Aviv, Israel. · Schneider Children’s Medical Center, Petah-Tikva, Israel. · Gray Faculty of Medical & Health Sciences, Tel Aviv University, Tel Aviv, Israel. · The Ivan and Francesca Berkowitz Family Living Laboratory Collaboration at Harvard Medical School and Clalit Research Institute, Ramat-Gan, Israel. · Faculty of Health Sciences, School of Public Health, Ben Gurion University of the Negev, Be’er Sheva, Israel.
Automated judges of clinical artificial intelligence (AI) outputs are necessary, but large language model (LLM) judges are costly and slow at scale. We compared Jev, a decision language model that returns structured judgments, with frontier and open-weight LLM judges in four use cases. On 118 pediatric answers, Jev's agreement with physicians' ordinal quality ratings (Gwet's AC2 0.50; expected score 0.53) matched or exceeded that of seven of 12 LLM judges, including frontier models, Claude Opus 5.5 (0.49) and GPT-6 (0.38). On physician-graded binary HealthBench criteria, Jev matched or exceeded four of six LLM judges. On MedHELM's open-ended tasks, Jev's agreement with a three-LLM jury approached or exceeded the jurors' internal agreement. On HealthBench Professional, Jev matched the benchmark's reference judge, GPT-5.4, on 91% of criteria (other judges, 91-93%). Frontier judges cost 73-294 times more than Jev and took 7-57 times longer. Jev may enable efficient clinical AI evaluation at scale.
Large language model (LLM)-as-a-judge research uses language models to score, compare, and verify AI outputs as scalable alternatives to human evaluation.
aWits MIND Institute, University of the Witwatersrand, Johannesburg, South Africa · fSchool of Computer Science and Applied Mathematics, University of the Witwatersrand, Johannesburg, South Africa · bGrai Labs, Cape Town, South Africa +3