Cases from the record · 1984 onward
Toyota andon at NUMMI
An obligation to stop the line
When Toyota and General Motors reopened a closed California plant, the workforce largely returned. What changed was who was expected to raise a problem, and what happened when they did.
Process lens Follow through
What happened
Toyota’s production system gives any worker on the line the means to stop it when something is wrong: a cord that signals for help and, if needed, halts the line at a fixed point. Toyota describes this as one of the two pillars of its system.
In 1984 Toyota and General Motors opened a joint venture, NUMMI, in a General Motors plant in Fremont, California that had closed in 1982. Most of the hourly workforce came from the old plant. The plant ran Toyota’s system, including the cord, until it closed in 2010.
General Motors closes its Fremont plant.
New United Motor Manufacturing, Inc. (NUMMI) is organized as a joint venture.
Team leaders and supervisors train at Toyota’s plants in Japan.
The first car is produced.
Quality moves from among General Motors’ worst to its best, by the project manager’s account.
NUMMI closes.
What the record shows
- 01
An obligation, not a right.
Asked whether workers would have the right to stop the line, Toyota answered, by one manager’s account: “No, we intend to give them the obligation to stop it — whenever they find a problem.”
- 02
A signal answered, not a line abandoned.
A pull calls the team leader, who comes to help within the worker’s job cycle; the line stops at a fixed position only if the problem needs it.
- 03
Managers had to change too.
Supervisors who kept reporting “no problem” were told, in the same account, that seeing problems was the manager’s job.
- 04
Practice was uneven.
A contemporary study records reports of about 100 pulls a day in final assembly, and a critic’s view that the cord was sometimes reset at once. The system depended on how leaders answered it.
Our reading · Follow through
Raising a concern costs something. Toyota lowered that cost by making it expected, by answering it within the worker’s own work cycle, and by treating a problem found as work done. The record of a concern is only as useful as the answer that follows it.
Context and limits
This is a positive example, not a success story without qualification: NUMMI closed in 2010, and the improvements came from training and management practice as much as from the cord. Widely repeated productivity comparisons are not printed here because their primary sources could not be confirmed.
From the record to a design question
When someone raises a problem, what response can they reliably expect?
What this asks of the process
Give follow-through a return path: an owner can report a changed condition, someone is responsible for reviewing it, and the decision can be revisited. A signal is useful only when the organization responds.
What we do not conclude
The cord was one part of a production and management system. A digital alert alone cannot reproduce Toyota’s training, routines, authority or workplace relationships.
This is our design inference from the case. The case does not test Sikizana. See the research that informs the sequence
Sources
- Toyota Motor Corporation, Toyota Production System
- Shook, J. (2010). How to Change a Culture: Lessons from NUMMI. MIT Sloan Management Review
- Adler, P. S. (1992). The “Learning Bureaucracy”: New United Motor Manufacturing, Inc. (draft, University of Southern California)
Based on the linked official record, participants’ accounts and original research. Retrospective accounts and investigations have different limits; they are not controlled tests of a decision method. No organization named here is presented as a customer, partner or endorser of The Third Field.