Were one to distill the advice of Edwards Deming to its essence, it would be “don’t tweak.” Respond to noise in a non disciplined fashion, and all you do is exacerbate what you meant to improve. Hence, Statistical Process Control to distinguish real problems from normal fluctuations in repeatable processes and PDCA cycle to impose the rigor of the scientific method on change. Of course, Deming was not the first to arrive at this view that discipline in design is a precursor to discipline in change.
Even the most rudimentary high school lab demands that an experiment be written before it is tried, that the equipment be cleaned to ensure the outcome is the result of the design, not the arbitrariness of dirt and other perturbations injected into the process. Do you know if a recipe worked? Only if you followed it.
So too with Toyota’s commitment to specification as a precursor to improvement. Without defining what you expect to do and what you expect to happen, you cannot meaningfully determine if what is happening is a bona fide problem or merely the result of work done out of control.
Hence, all the famous tools of TPS carried over into the lean world, and the many others not so popularized, all do double duty (when used as at Toyota–a very strong qualifier): They help specify what is predicted/expected of a process design and make clear when reality departs from that prediction.
Two anecdotes on which to end.
One: When I was doing my research with Toyota (and still to this day), I couldn’t visit a site without first predicting what I expected to see and what I expected to learn. If I didn’t, how could I legitimately be surprised that I had seen anything new?
Two: I was on the phone with the head of a major retailer and along time Toyota veteran. After the retailer went on and on and on about hsi firm’s commitment to kaizen, the kaizen spirit, and continuous change, the Toyota vet finally commented:
“You just don’t get it, do you?”
“What do you mean?” was the response?
“You think we’re all about change this change that. But you have no idea how hard we work to first standardize and stabilize before we make changes.”
“What do you mean?
“Well, what we do is really really complicated. If we did what you describe, we would never get better by learning day in day out. We would just be churning fruitlessly.”
In short: design work so learning is an inevitable consequence. If you don’t make that investment, life is lived on nothing but a chattering plateau.
adapted from Steve Spear