What is Poka-Yoke?

What Is Poka-Yoke

In Japanese, Poka Yoke - ポカヨケ - means to mistake-proof or to prevent errors.
It’s a Lean practice that will prevent accidental mistakes from occurring by error-proofing an operation or activity.
Lean and project management training teach that you should never inspect quality, to cut expenses. The goal is to always build quality in - but what does that mean, and how can your Kanban team benefit from this practice? You will be glad to find out how Poka-Yoke can help your company in this matter, and that it’s not a Russian folk dance, as many tend to think on initial contact with the term!

Don’t inspect quality it in, build it in!

The Toyota Production System, which was later renamed to Lean by the researchers at MIT, leaned (pardon the pun) heavily on the teaching of W.Edwards Deming.
Deming actually travelled to Japan and had a profound impact on its industries. He explained that if you have someone watching a production line and inspecting items for quality, by the time they have found the cause of the defect, the damage has already been done and cost incurred. It is far better to make sure that defects don’t make it to production in the first place.

Error proofing, or Poka-Yoke

The Toyota Production System was truly blessed with some of the best minds of that century. There was an engineer there by the name of Shigeo Shingo, who not only documented the TPS for the West, but was intricately involved with quality on their manufacturing line. His was the concept of mistake-proofing - or Poka-Yoke - that is still taught today.

What does Poka-Yoke look like?

We have grown so accustomed to this practice that we don’t even notice it any more. But think back to a few years ago, it was not uncommon to fill out an entire online form, hit submit and be told that you had filled it out incorrectly, and had to start from scratch. Now we have built-in intelligence, which follows your edits in real-time, to tell you whether each field is filled correctly or not. Better still, sometimes the field is presented in such a way, for example in a date format, that you have no choice but to fill it in correctly the first time!

Kanban boards have the Poka-Yoke concept built-in as well. Once you have stipulated your Work In Progress limit for a particular column, the board will keep you in check so as not to allow for more work to be allocated to that column.

Poka-Yoke should work in tandem with Kaizen and Gemba in your Kanban practice. Not only will they improve your quality - they can even save lives. Think of elevators, used to warning people to stand clear of the closing door, to the new improved Poka-Yoke equivalent of having sensors on the door that will not allow the doors to close, if an obstacle is detected. Poka-Yoke is a practice of mature Kanban and good design, and all products and processes should strive for its inclusion for best results.