Poo-pooing Deviation Value (偏差値)

Very intelligent discussion with my mentor Hiro

Masahiro (Hiro) Nakagawa
3 min readOct 22, 2021

Coaching from Sub Zero — fighting against COVID-19 with Zoom / Autumn-Winter 2021–22 / Week 5

Credit; Hiro Nakagawa @ Acqualine, Tokyo

Last weekend was an annual Takeuchi Zemi Golf and I am honored to be a chauffeur for Hiro Takeuchi sensei and his wife Nobu-san. 50 miles drive to the golf course are always my precious moment with lots of updating, sometime at very private topics. At some topic of education, Takeuchi sensei asked me, simply,,

“Hiro, how do you calculate Deviation Value (偏差値) ?”

Takeuchi Sensei is lifetime tenure Professor of Harvard Business School and Chancellor of International Christian University (ICU, Tokyo), and this question is not to be expected to answer the formula of;

(Your Score — Average Score) / Standard Deviation x 10 + 50

This protocol is at very high level of discussion on how Japanese education system are too closed. In Japan (and in Korea and at some Chinese region), Deviation Value is a kind of “religion” to evaluate the school and students domestically. Already Japan’s tutoring industry are at US$ 20 billion value and one of the largest industries in my country. But this “Deviation Value”…