Changes in the number of doctoral degree holders in computational materials science in Japan -recent diversity of research fields-

There have been few quantitative analyses regarding the change in the number of doctoral degree holders (doctors) in computational materials science (CMS) in Japan.
We analyzed the subjects of more than 150 thousand doctoral dissertations in the fields of traditional engineering and science (ES) found in a Japanese doctoral dissertation database. We estimated the change in the number of doctors in CMS in Japan using text data mining techniques. As a result of the analysis, we found that the ratio of doctors in CMS to those in traditional ES has continued to increase, closing to 0.1 in 2018.
Due to a review of Japanese higher education system after 1991, names of stipulated doctoral degree have been changed by law. Appropriate major has been added to doctoral degree, not only traditional majors like engineering and science, but also new majors such as mathematical science, information science, and so on. Though the traditional majors are dominant even now, we also found that the ratio of CMS doctoral degree holders in new majors is bigger than those in traditional fields.