Poka-Yoke Design Worksheet

What it is and when to use it

Telling someone to “be more careful” doesn't survive a busy shift, a new hire, or hour ten of a long day — the same mistake comes back. Poka-yoke works through error-proofing designed at three levels: prevention (the error can't physically happen), detection (it's caught before it moves to the next step or the customer), and alert (it's flagged so a person can act). This worksheet walks a failure mode through the three levels in order, because most fixes stop at the cheapest one — an alert — when a prevention-level fix was available for not much more.

What goes on the sheet

1. Failure mode: the specific error being designed against, and how often it currently occurs
2. Current control level, if any (none / alert / detection / prevention)
3. Prevention option considered: can the error be made physically impossible, and at what cost
4. Detection option considered: how the error would be caught before the next step, and at what cost
5. Alert option considered: what signal would flag it, and who's responsible for acting on it
6. Level selected, and the reason it was chosen over a higher level (cost, feasibility — stated explicitly)
7. Verification: how the fix will be tested to confirm the failure mode is actually prevented, not just less frequent

In a business like yours

• Soap or gift-box company: a shaped tray makes the wrong product physically impossible to pack.
• Pharmacy counter: look-alike items stored apart and scanned before bagging.
• Installer crew: a checklist that cannot be closed until a photo of each step is attached.

Illustrative examples, not client cases.