POKA YOKE

Description

Poka Yoke is a method aimed at error reduction in the process that seeks to eliminate, reduce or detect errors. This is also known as 'Mistake Proofing'.

When

In the Thinking Improvements phase.

Goals

Identify and remove possible errors in the process or try to prevent and/or detect them as much as possible. This can be done by removing, replacing, facilitating, detecting or reducing the impact of the error.

Steps

Identify possible errors in the process.

Apply one of the five principles to the identified errors.

Delete: can you easily eliminate the possibility of the error? Some processes can be completely or partially redesigned to eliminate the possibility of making the mistake.
Replaced: Can you replace the error-prone process step with a more reliable process step? For example, automation can increase consistency.
Facilitate: can you make the task easier by, for example, using visual management, such as colour coding and so on? Perhaps combine tasks so that they are completed in one go.
Detection: can you develop a way that reveals the errors before they go to the next process step? For example, computer software alerts the user if a field is not filled in or if you divide by 0.
Reduce impact: can you reduce the effect of an inevitable error? For example, a fuse in an electrical circuit.

Examples

Figure: Examples Poka Yoke

Tips:

Keep it practical.
Measure the effect after introduction.
It doesn't have to be perfect. If there is a chance of a 50 per cent improvement then it is definitely worth a try.
Create a flow chart of the process and follow a mistake-proofing procedure.
Start as early as possible in the product life cycle.