In 2018, a total of 8,410 residents began residency training under the new board certification system in Japan. The number of new residents for each specialty in 2018 were as follows: internal medicine: 2,670, surgery: 805, paediatrics: 573, orthopaedics: 552, anaesthesiology: 495, obstetrics and gynaecology: 441, ophthalmology: 328, dermatology: 271, urology: 274, emergency medicine: 267, otolaryngology: 267, radiology: 260, neurosurgery: 224, general practice: 184, plastic surgery: 163, pathology: 114, rehabilitation: 75, and clinical examination: 6 . According to a survey conducted by the Japanese Medical Specialty Board, approximately 85% of young physicians chose their specialty during medical school and junior residency . Thus, factors that elucidate the choice of medical specialty among medical students are of great significance, especially in recruitment for each specialty.
Previous studies have demonstrated several factors associated with medical students’ specialty choice. Kassebaum et al. have demonstrated that medical school graduates who chose primary care tended to be female, older, had a rural background, and preferred intellectual challenges . Another study conducted at the University of Wisconsin revealed that primary care students placed emphasis on understanding populations, relationships with patients, and scope of practice, while salaries and competitiveness were not at as important to them . Vaidya et al. found that surgery, emergency medicine, and gynaecology and obstetrics students demonstrated a higher ‘novelty seeking’ tendency. They also reported that surgery students had lower ‘harm avoidance’ and ‘reward dependency’ scores. In contrast, students who chose primary care, emergency care, and gynaecology and obstetrics had a high ‘reward dependency’ .
As aforementioned, the concept by Weiss et al. that medical students may chose a cluster of related specialties based on a cluster of socio-economic and occupational features  might be particularly useful in understanding the process of specialty choice. Our exploratory factor analysis and the subsequent multilevel logistic regression analyses revealed that career priorities under the ‘primary care orientation’ category had positive association with choosing general practice, emergency medicine, internal medicine, and paediatrics, all of which could potentially have some primary care aspects. The ‘advanced and specific care’ career priorities facilitated surgery and emergency medicine choices while reducing the likelihood of less procedure-oriented specialties, such as internal medicine, general practice, and paediatrics. Intriguingly, those who had chosen ‘advanced and specific care’ related specialties (surgery and emergency medicine) rated lower perceived importance in ‘personal life orientation’.
This study has several limitations. First, the cross-sectional data might not reflect medical students’ actual career choice. Thus, our models need to be validated in the future using longitudinal cohort of medical school graduates. Secondly, social desirability response bias may have led to ceiling effects on several career priority variables, which could undermine the discrimination capacity of the models. The relatively large sample size may have amplified the small effects. In addition, our results may not be applicable to junior residents since the study was limited to undergraduate medical education.