In Lean thinking errors or mistakes are seen as opportunity for improvement and growth. But in lean, mistakes don’t come alone, they also provide an opportunity for the team to create a poka-yoke tool/device. Poka-yoke stands for “mistake proofing”, i.e. making sure the same mistake does not happen again. This can only be done by changing the process or tools.
All of these things stem from the most important value in Lean Thinking: Respect for people.
When Toyota started exporting their ideas outside Japan they found out that in some countries the culture was to “blame”, not to reward the honesty of admitting a mistake.
There’s this story (thanks for the link Jukka!) of an american enginner (let’s call him Mike) working in Japan. Mike was working on the line and while assembling a part in the car he scratched the paint. Influenced by his culture he was afraid of admitting the mistake, so he thought twice before pulling the andon cord (the device that notifies others when there is a problem). After a few seconds of struggling with the dilemma he pulled the cord and waited. The team leader immediately came to the workstation and was able to fix the defect quickly. The line did not stop.
At the end of the day while the daily meeting was going on the team had brief exchange in Japanese that Mike did not understand, but his fear was that they were just criticizing him in Japanese so that he would not feel so bad. He was wrong. Soon after that the team started applauding and looking at Mike, he was confused. When asked, the supervisor clarified: “the team was proud of you admitting the mistake and wanted to express that!”.
This is why mistakes should be “admitted” by those who make them, not just “blamed on” the people that made them. Admitting the mistake and wanting to improve based on the learning is the most important part of surfacing the mistakes and “stopping and fixing”. A culture that only assigns blame for mistakes will only create a need to hide those mistakes.
Let people admit their mistakes and create a welcoming environment where people actually will be proud of surfacing and fixing their mistakes. Don’t just blame, blame kills improvement.
Update: Updated to add link to the story about Toyota.