As I beat the morning traffic on my way to work I felt immensely proud. This particular journey to our Cheshire office from Liverpool is 60 percent timing and 40 percent luck. However, my sense of achievement rapidly dwindled as I realised I had left my laptop at home. With all my work on my laptop I had to join the morning traffic back to Liverpool. Embarrassingly, this wasn’t the first time I had done this, so on my way home I thought of a way that I could mistake-proof this from happening again. While at first I thought of elaborate ideas such as online file sharing software, I instead came up with a simple idea – put my bags in front of the door every night.
Part of continuous improvement is building in mistake-proofing systems that will enable the process to run smoothly while reducing defects. This is also known as Poka-Yoke, but that’s the last time you’ll see a Japanese word in this article. Don’t let the Japanese name put you off, it’s an easy concept to grasp and in this article I’ll talk you through it.
Mistake-proofing is making it difficult for defects to be carried over to the next step in your process. This can be physical devices or systems such as specially designed instruments or colour systems; or it can be computer software such as those that require specific data and formats before allowing the user to continue.
There are many examples of this in your everyday life, such as cash machines. Cash machines give you your card back first before providing you the money. This is to prevent you leaving your card in the machine.
There are two mistake proofing systems: the control approach and the prevention approach.
Control approach: gives a signal that a defect has occurred – for example, a production machine stopping automatically if the product does not meet specifications.
Prevention approach: stops mistakes happening in the first place – misfuelling – the nozzle of a diesel petrol pump is too large to fit in the filler neck of an unleaded tank.
Mistake-proofing can be part of a larger continuous improvement project or it can be a mini project itself. Below are 10 simple steps to successfully achieve mistake proofing:
- Identify and describe the defect that is affecting the customer.
- Identify the step in the process where the defect occurs and the step where the defect is found.
- Review the standard operating procedure where the defect is occurring.
- Identify any errors or deviations within the standard operating procedure.
- Perform a Root Cause Analysis on these errors or deviations.
- Use Brainstorming to find ways of preventing or quickly identifying the defects.
- Create the solution based on your brainstorm.
- Test the solution in a controlled area.
- Review the solution and how well it worked. Make any improvements as necessary.
- Implement your mistake-proofing system.
Mistake-proof systems don’t need to be expensive or complex. While an online file sharing facility would have helped me if I forgot my laptop in the future, it’s far easier not to forget my laptop at all and putting my bags by the front door every night is an easy and cost effective way of mistake-proofing.