Chatbots in urology: accuracy, calibration, and comprehensibility; is DeepSeek taking over the throne?

OBJECTIVE: To evaluate widely used chatbots' accuracy, calibration error, readability, and understandability with objective measurements by 35 questions derived from urology in-service examinations, as the integration of large language models (LLMs) into healthcare has gained increasing attention, raising questions about their applications and limitations. MATERIALS AND METHODS: A total of 35 European Board of Urology questions were asked to five LLMs with a standardised prompt that was systematically designed and used across all models: ChatGPT-4o, DeepSeek-R1, Gemini, Grok-2, and Claude 3.5. Accuracy was calculated by Cohen's kappa for all models. Readability was assessed by Flesch Reading Ease, Gunning Fog, Coleman-Liau, Simple Measure of Gobbledygook, and Automated Readability Index, while understandability was determined by scores of residents' ratings by a Likert scale. RESULTS: The models and answer key were in substantial agreement with a Fleiss' kappa of 0.701, and Cronbach's alpha of 0.914. For accuracy, Cohen's kappa was 0.767 for ChatGPT-4o, 0.764 for DeepSeek-R, and 0.765 for Grok-2 (80% accuracy for each), followed by 0.729 for Claude 3.5 (77% accuracy) and 0.611 for Gemini (68.4% accuracy). The lowest calibration error was found in ChatGPT-4o (19.2%) and DeepSeek-R1 scored the highest for readability. In understandability analysis, Claude 3.5 had the highest rating compared to others. CONCLUSION: Chatbots demonstrated various powers across different tasks. DeepSeek-R1, despite being just released, showed promising results in medical applications. These findings highlight the need for further optimisation to better understand the applications of chatbots in urology.