Performance of Generative Pretrained Transformer on the National Medical Licensing Examination in Japan
Authors: Tanaka Yudai , Nakata Takuto , Aiga Ko , Etani Takahide , Muramatsu Ryota , Katagiri Shun , Kawai Hiroyuki , Higashino Fumiya , Enomoto Masahiro , Noda Masao , Kometani Mitsuhiro , Takamura Masayuki , Yoneda Takashi , Kakizaki Hiroaki , Nomura Akihiro 
Published: April 2023

The remarkable performance of ChatGPT, launched in November 2022, has significantly impacted the field of natural language processing, inspiring the application of large language models as supportive tools in clinical practice and research worldwide. Although ChatGPT recently scored high on the United States Medical Licensing Examination, its performance on medical licensing examinations of other nations, especially non-English speaking nations, has not been sufficiently evaluated. This study assessed ChatGPT’s performance on the National Medical Licensing Examination (NMLE) in Japan and compared it with the actual minimal passing rate for this exam. In particular, the performances of both the GPT-3.5 and GPT-4 models were considered for the comparative analysis. We initially used a model and prompt tuning set of 290 questions without image data from the previous 116thNMLE (held in February 2022) to maximize the performance for delivering correct answers and explanations of the questions. Thereafter, we tested the performance of the best ChatGPT model (GPT-4) with tuned prompts on a dataset of 262 questions without images from the latest 117thNMLE (held in February 2023). The best model with the tuned prompts scored 82.7% for the essential questions and 77.2% for the basic and clinical questions, both of which sufficed the minimum passing rates of 80.0% and 74.6%, respectively. Simultaneously, we identified the three major factors contributing to the generation of the incorrect answers—insufficient medical knowledge, information on Japan-specific medical system and guidelines, and mathematical errors. In conclusion, GPT-4 powered ChatGPT with our optimally tuned prompts achieved a minimum passing rate in the latest 117thNMLE in Japan. Although we express strong concerns regarding the use of the current ChatGPT for medical purposes so far, these artificial intelligence models may soon have the potential to serve as one of the best “sidekicks” for solving medical and healthcare problems.

Author summary

ChatGPT’s remarkable performance has inspired the use of large language models as supportive tools in clinical practice and research. Although it scored well in the US Medical Licensing Examination, its effectiveness in relevant examinations of non-English speaking countries remain unexplored. This study assessed the performance of ChatGPT with GPT-3.5 and GPT-4 models in Japan’s National Medical Licensing Examination (NMLE). Initially, we used a tuning set of 290 questions from the 116th NMLE, and then the GPT-4 model with tuned prompts was tested on 262 questions from the 117th NMLE. The model scored 82.7% for essential and 77.2% for basic and clinical questions, surpassing the minimum passing rates. Incorrect answers were attributed to insufficient medical knowledge, Japan-specific medical system information, and mathematical errors. In conclusion, GPT-4 powered ChatGPT achieved a minimum passing rate and might have the potential for a valuable tool for fulfilling the needs of medical and healthcare fields.