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The Psychometrics Centre

University of Cambridge Judge Business School

Studying at Cambridge


Dr Tomoya Okubo


Dr Tomoya Okubo is a member of the e-Psychometrics Unit in the Psychometrics Centre at the University of Cambridge, on an Academic Visit from his host institution, the National Centre for University Entrance Examinations, Tokyo, Japan. He graduated with a BA in Psychometrics from Waseda University, Tokyo, in 2002, following this with an MSc at the Tokyo Institute of Technology in 2004. His PhD, entitled 'Modeling view-point-shift by Latent Class Model and research on the treatment of missing data' was awarded in 2007.

Tomoya has a distinguished career as a psychometrician. He is an Assistant Professor in the Department of Test Analysis and Evaluation at the Japanese National Center for University Entrance Examinations, and also holds a Fellowship from the Japan Society for the Promotion of Science. He is a Lecturer in the Graduate School of Decision Science and Technology at the Tokyo Institute of Technology and in the Department of Economics at Saitama University, Japan. Additionally, he is a member of the Psychometric Society, the Behaviormetric Society of Japan, the Japan Association for Research in Testing and the Japan Evaluation Society.

As well as being knowledgeable in all the computer languages favoured by psychometricians, including SAS, JMP, Mathematica and Mplus, Dr Okubo is an accomplished software developer, using the R environment to develop new routines for item response theory solutions to complex psychometric data. He frequently presents papers at psychometric conferences and meetings, both in Japan and worldwide. Tomoya's interests include historical architecture and the role of the Japanese novel in modern literature.

to email Tomoya 

Key Publications

Tsugawa, Y., Tokuda, Y., Ohbu, S., Okubo, T., & Cruess, R., et al. (in press). Professionalism mini-evaluation exercise for medical residents in Japan: a pilot study. Medical Education.

Okubo, T., Nakamura, K., & Mayekawa, S. (2009). A formulation of the latent class vector model for pair-wise data. Proceedings of the World Academy of Science, Engineering and Technology. 54. pp.539-542.

Okubo, T. (2009). A programme for estimation of item parameters in item response theory with mixed item types, finite mixture model and multi-group model. DNC research note. RN-07-18. pp.1-15.

Okubo, T., & Shimoda, A. (2009). Analysing growth and developmental data using item response theory. Growth and Development Research of Children. 7(1). pp. 15-20. (In Japanese)

Tokuda, Y, Okubo, T., & Ohde, S., et al. (2008). Assessing items on the SF-8 Japanese version for health-related quality of life: a psychometric analysis based on the nominal categories model of item response theory. Value in Health. 12(1). e-pub ahead of print.

Okubo, T., Shojima, K., & Ishizuka, T. (2008). An analysis of test data including a multiple-choice multiple-answer item using the nominal categories model. The Japanese Journal for Research onTesting. 4. pp.125-133. (In Japanese with English abstract)

Shimoda, A., Ohsawa, S., & Okubo, T. (2008). A process of “the technique of the body” for weaving in the society without writing (Sgaw Karen Community) – using item response theory. Japan Journal ofHuman Growth and Development Research. 37. pp.1-8. (In Japanese with English abstract)

Nakamura, K., Okubo, T., & Mayekawa, S. (2008). A multidimensional scaling approach to verbal probability phrases. In K. Shigemasu, A. Okada, T. Imaizumi, & T. Hoshino (Eds.), New Trends inPsychometrics, pp.329-338. Tokyo: Universal Academic Press.

Okubo, T. (2007). Measurement of the ability using item response theory. Statistical Information. 10. pp.42-45. (In Japanese)

Okubo, T., Ohsawa, S., & Nakagawa, M. (2006). Scaling of AIDS knowledge test items for Japanese junior high school students. School Health. 2. pp.27-32.

Okubo, T., et al. (2005). Statistical analysis of rating data. The Japanese Journal of Evaluation Studies. 5(1). pp.1-14. (In Japanese with English abstract)

Okubo, T. (Ohsawa, S. (Ed.)) (2004). Encyclopaedia of school health and school education. Tishu-kan Shoten. (wrote 15 items concerning psychometric terms).

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