Kazuya Nagasaki,1 Yuji Nishizaki,2,3 Masanori Nojima,4 Taro Shimizu,5 Ryota Konishi,6 Tomoya Okubo,7 Yu Yamamoto,8 Ryo Morishima,9 Hiroyuki Kobayashi,1 Yasuharu Tokuda10 1Department of Internal Medicine, Mito Kyodo General Hospital, University of Tsukuba, Ibaraki, Japan; 2Medical Technology Innovation Center, Juntendo University, Tokyo, Japan; 3Division of Medical Education, Juntendo University School of Medicine, Tokyo, Japan; 4Center for Translational Research, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan; 5Department of Diagnostic and Generalist Medicine, Dokkyo Medical University Hospital, Tochigi, Japan; 6Education Adviser Japan Organization of Occupational Health and Safety, Kanagawa, Japan; 7Research Division, The National Center for University Entrance Examinations, Tokyo, Japan; 8Division of General Medicine, Center for Community Medicine, Jichi Medical University School of Medicine, Tochigi, Japan; 9Department of Neurology, Tokyo Metropolitan Neurological Hospital, Tokyo, Japan; 10Muribushi Okinawa for Teaching Hospitals, Okinawa, JapanCorrespondence: Yuji NishizakiMedical Technology Innovation Center, Juntendo University, 2-1-1 Hongo Bunkyo-ku, Tokyo, 113-8421, JapanTel +81-3-3813-3111Fax +81-3-5689-0627Email ynishiza@juntendo.ac.jpPurpose: In Japan, the General Medicine In-training Examination (GM-ITE) was developed by a non-profit organization in 2012. The GM-ITE aimed to assess the general clinical knowledge among residents and to improve the training programs; however, it has not been sufficiently validated and is not used for high-stake decision-making. This study examined the association between GM-ITE and another test measure, the Professional and Linguistic Assessments Board (PLAB) 1 examination.Methods: Ninety-seven residents who completed the GM-ITE in fiscal year 2019 were recruited and took the PLAB 1 examination in Japanese. The association between two tests was assessed using the Pearson product-moment statistics. The discrimination indexes were also assessed for each question.Results: A total of 91 residents at 17 teaching hospitals were finally included in the analysis, of whom 69 (75.8%) were women and 59 (64.8%) were postgraduate second year residents. All the participants were affiliated with community hospitals. Positive correlations were demonstrated between the GM-ITE and the PLAB scores (r = 0.58, p < 0.001). The correlations between the PLAB score and the scores in GM-ITE categories were as follows: symptomatology/clinical reasoning (r = 0.54, p < 0.001), physical examination/procedure (r = 0.38, p < 0.001), medical interview/professionalism (r = 0.25, p < 0.001), and disease knowledge (r = 0.36, p < 0.001). The mean discrimination index of each question of the GM-ITE (mean ± SD; 0.23 ± 0.15) was higher than that of the PLAB (0.16 ± 0.16; p = 0.004).Conclusion: This study demonstrates incremental validity evidence of the GM-ITE to assess the clinical knowledge acquisition. The results indicate that GM-ITE can be widely used to improve resident education in Japan.Keywords: in-training examination, validity, extrapolation, General Medicine In-Training Examination, Professional and Linguistic Assessments Board, medical knowledge, postgraduate medical education