Nakajima's 1982 formulation of OEE
A composite metric named overall equipment effectiveness (OEE, 設 備 総 合 効 率 ) was first proposed by Seiichi Nakajima ( 中 嶋 清 一 ) in early seventies. In his 1982 book (Deploying TPM At at the time when the book was written, the M in TPM means maintenance and not management. Program for Reforming Manufacturing, 生 産 革 新 のためのTPM 展 開 プログラム), the following formulation was given: \begin{align} {\small 設備総合効率} &＝ {\small 時間稼働率} \times {\small 性能稼働率} \times {\small 良品率}\\ \eta_{\rm oee} &= \eta_{\rm time} \times \eta_{\rm rate} \times \eta_{\rm quality} \end{align} The first ratio, 時 間 稼 is a kanji formed from the semioglyph 禾 (meaning rice or other cash crops) and the audioglyph 家, while 働 is a kanji formed from the two semioglyphs: 人/亻 (people) and 動 (move). Together, 稼働 can be taken to mean people working in the paddy field. When the context is changed from human to machine, the word 稼働 means that the equipment is in running or operating mode. 稼 働 率 , \beg