I am honored to be part of Uganda’s most successful management consultancy firm “Next Lean” that utilizes the principles of Lean and Six Sigma. One of the things we always teach our clients is the concept of mistake-proofing aka Poka-Yoke.
I remember when I used to intern at Mukwano Industries. I would meet these people with the fingers slightly chopped by the machine that sliced soap bars. I kept on wondering; “how come more people continue to have their hands suffer at this machine?” All the way to the top most engineer, I would get no answer.
That’s when it hit me that they were clueless about what to do. Yet, they could have found a way to mistake-proof this process. In our final report, we recommended machine guarding so that the moment someone opened the guard while the machine was running, it would go off.
Because we are humans, we are prone to mistakes. We can’t avoid falling prey to our mistakes but we can minimize the consequences of our mistakes or catch ourselves in the process of making those mistakes. For example, most cars now won’t start unless the seat belt is on.
When ATMs had just come to Uganda, people used to withdraw money and forget to take their cards. In order to mistake proof the process, the banks arrived at a simple solution. The machine would not release money until the customer had taken out their card. As a result, the incidences of people leaving their ATM cards in the machine almost became history.
As you build a system, you must figure out all ways to mistake-proof it. Whenever I find managers complaining about employees having committed a certain mistake, I ask them one important question; “did you mistake-proof that?” Do you have a Poka-Yoke in place for that issue in particular?
As Shigeo Shingo said; “defects will never be reduced if workers involved do not modify operating methods when defects occur.” I guess, Next Lean is building its silent revolution of error-proofing systems.