Estimate how effective a mistake-proofing countermeasure is by comparing before-and-after
error rates, then translate the result into a likely Poka-Yoke category with practical
implementation guidance.
Estimator
Enter the pre- and post-countermeasure error rates
Core logic:
Effectiveness = (before rate - after rate) / before rate
How to interpret the result
Higher effectiveness means the countermeasure eliminates or blocks a larger share of the original error opportunity.
Contact methods usually prevent the error physically, fixed-value methods verify the expected count, and motion-step methods ensure the required sequence happened.
If the after rate is still material, the best next move is often shifting from detection to prevention rather than adding more inspection.
Recommendation
Category guidance
The chosen method relies on part presence, orientation, or physical confirmation, which aligns most closely with a contact Poka-Yoke.
Implementation note: strengthen fixture repeatability or sensor reliability so the device stops the error before the process continues.
Next step: if residual risk remains high, move the control earlier in the process or make the incorrect condition impossible to assemble.
Category Types
What the categories mean
Category
Typical Use
Strength
Contact
Part presence, fit, orientation, geometry, sensor confirmation
Strongest when the wrong condition can be physically blocked
Fixed-value
Count checks, quantity verification, torque or cycle confirmation
Strong when process order matters more than geometry
Instructions
How to use this app
Enter the observed error rate before the countermeasure and the rate after it was installed.
Then choose the method type that best matches how the device or control works in practice.
The app converts the improvement into an effectiveness percentage, estimates how many errors
were avoided over the processed volume, and recommends the most likely Poka-Yoke category:
contact, fixed-value, or motion-step.
Use the recommendation as a design and coaching aid. If your current solution is only
detecting errors, the best follow-up is often redesigning the process so the error becomes
impossible rather than merely visible.
