Performance of large language models on family medicine licensing exams

Background and Aim Large language models (LLMs) have shown promise in specialized medical exams but remain less explored in family medicine and primary care. This study evaluated eight state-of-the-art LLMs on the official Israeli primary care licensing exam, focusing on prompt design and explanation quality. Methods Two hundred multiple-choice questions were tested using simple and few-shot Chain-of-Thought prompts (prompts that include examples which illustrate reasoning). Performance differences were assessed with Cochran's Q and pairwise McNemar tests. A stress test of the top performer (openAI's o1-preview) examined 30 selected questions, with two physicians scoring explanations for accuracy, logic, and hallucinations (extra or fabricated information not supported by the question). Results Five models exceeded the 65% passing threshold under simple prompts; seven did so with few-shot prompts. o1-preview reached 85.5%. In the stress test, explanations were generally coherent and accurate, with 5 of 120 flagged for hallucinations. Inter-rater agreement on explanation scoring was high (weighted kappa 0.773; Intraclass Correlation Coefficient (ICC) 0.776). Conclusions Most tested models performed well on an official family medicine exam, especially with structured prompts. Nonetheless, multiple-choice formats cannot address broader clinical competencies such as physical exams and patient rapport. Future efforts should refine these models to eliminate hallucinations, test for socio-demographic biases, and ensure alignment with real-world demands.