Feb 20 2022
Dec 7 2020
Thanks to Jeffrey Liker for providing additional details on the transformation of this tool. Initially, Toyota used it occasionally with suppliers. The Lean Enterprise Institute (LEI) turned it into the Value Stream Maps (VSM) that it has promoted as foundational to Lean.
Oct 30 2020
Next to SPC, Design of Experiments (DOE) is the most common topic in discussions of Statistical Quality. Outside of niches like semiconductors or pharmaceuticals, however, there is little evidence of use, particularly in production.
At many companies, management pays lip service to DOE and even pays for training in it. You must “Design experiments” if you pursue continuous improvement.
In manufacturing, DOE is intended to help engineers improve processes and design products. It is a rich but stable body of knowledge. The latest major innovation was Taguchi methods 40 years ago. Since then, Statistics has been subsumed under Data Science and new developments have shifted in emphasis from experimentation to Data Mining.
Experimentation in science and engineering predates DOE by centuries. Mastering DOE is a multi-year commitment that few manufacturing professionals have been willing to make. Furthermore, its effective use requires DOE know-how to be combined with domain knowledge.
Six Sigma originally attempted to train cadres of engineers called “Black Belts” in a subset to DOE. They then served as internal consultants to other engineers within electronics manufacturing. Six Sigma, however, soon lost this focus.
Sep 26 2020
The post on Does Toyota Use SPC? elicited many comments on LinkedIn. Some suggested that it was scoping SPC too narrowly when contrasting it with Toyota’s approach. In fact, SPC as referenced in the post is the body of knowledge described in the American literature on quality and taught in professional courses.
As to why Toyota is not using SPC, the answer is simple: SPC is about process capability and the quality problems Toyota addresses in 2020 are not due to lack of process capability. In industries that lack process capability, modern data science outguns the old SPC toolkit but that is a different discussion. The most vital question raised in the comments was why we have been not learning Toyota’s approach to quality. In the past 30 years, American industry has learned “Lean Six Sigma” instead.
The comments also enriched the public sources of information cited in the post with corroboration by current and former employees of Toyota.
Sep 21 2020
As part of a discussion started by Lance Richardson on LinkedIn, I stated as a fact that SPC was not part of the Toyota Production System (TPS), which prompted several contradictors to tell me I didn’t know what I was talking about. The “evidence” they provided, however, does not refute my statement. It confirms it instead.
Jun 17 2019
Quoted by Jun Nakamuro on LinkedIn from a podcast.
Michel Baudin‘s comments: To be fair, Dr. Migita is a pediatrician with 20 years of experience. His podcast is about adapting TPS to health care, not to “any setting.” It is an interview, a format that can trip up anybody.
What I find remarkable throughout is that Migita does not hide behind the word “Lean.” He explicitly refers to Toyota and Taiichi Ohno and vigorously asserts that you can borrow ideas for car making to improve patient care.
This opening sentence in Jun Nakamuro’s quote, however, makes TPS sound like Shimmer, the product once advertised on Saturday Night Live as “both a dessert topping and a floor wax.” It almost kept me from listening further.