The Same Quality Problem Keeps Coming Back
A defect or equipment failure that comes back was never root-caused, or the fix depended on people remembering. Closing the corrective action is easy. Making the problem hard to repeat takes evidence, a fix at the cause, and a check that it held.
What Is Usually Going On
- The root cause was "operator error" and the action was retraining.
- The 5 Why stopped at the first plausible answer, with no evidence.
- Only one path was fixed when the defect has two: why it was made and why it escaped.
- Nobody checked weeks later whether the fix held.
How to Fix It
- Contain firstProtect the customer: sort, inspect, hold. Containment is not the fix.
- Define it with dataWhat, where, when, how many. Which units, which shift, which machine.
- Run two 5 WhysOne for why it was made, one for why it was not caught. Back each why with evidence.
- Fix at the causePrefer mistake-proofing and design changes over retraining and added inspection.
- VerifyCheck the data weeks later, over enough units that the defect would have shown up. If it came back, the cause was wrong.
- Spread itApply the fix to similar parts, machines and lines. Update the FMEA and standard work.
Start Free
Guides and web tools on this site. No account needed.
When It Moves to the Floor
The same work as an offline file you keep: saved scenarios, print and export, no internet needed on the floor.
Common Questions
Is operator error ever a root cause?
Rarely. Ask why the process let the error happen and why it was not caught. That is where the fix goes.
How do I know the fix worked?
Pick the measure before you change anything, then check it over enough units and weeks that the defect would have shown up.
Containment or corrective action?
Containment protects the customer now. Corrective action removes the cause so the containment can come off.
When should I use an A3?
When the fix needs more than one person and someone has to approve the countermeasure. The A3 is the story on one page.