Most CAPA registers close 80% of items within thirty days and reopen a third of them within six months. The pattern is almost always the same: the root cause was the symptom, the corrective action was retraining, and effectiveness was never verified. This guide covers the method we teach for CAPA that actually closes and stays closed.
Vague problem statements produce vague root-causes. 'Coating defect on Line 3' is not a problem statement; 'On 12 March, 14 of 42 painted assemblies from Line 3 exhibited orange-peel on the horizontal surfaces at DFT below 80 microns, versus a specification of 100 microns minimum' is. The specificity of the problem statement sets the ceiling for how good the root-cause can be.
Simple recurring issues: 5 Why is sufficient — but stop at a cause you can act on, not at 'human error'. Complex or multi-factor defects: fishbone (Ishikawa) diagram to structure man/machine/method/material/measurement/environment. Safety-critical or systemic failures: fault-tree analysis for the primary event and 5 Why for each contributory branch. Document the method used and the evidence supporting each level.
If the root cause is 'no visual acceptance criterion for surface preparation before coating', the corrective action is 'issue a photo-based acceptance standard and train inspectors on it'. Retraining alone, without the standard, changes nothing. If the root cause is 'measurement equipment out of calibration', the corrective action includes both re-verifying the equipment and reviewing every part inspected since the last known-good calibration.
Close CAPA in two stages, not one. Stage 1 — Corrective action complete: the change has been made, the procedure issued, the training delivered. Stage 2 — Effectiveness verified: at a defined interval (typically 60–90 days) re-sample the process and confirm the defect has not recurred. Only after Stage 2 is the CAPA closed. Registers that skip Stage 2 will always show low reopen rates on paper and high recurrence rates in reality.
CAPA stands for Corrective and Preventive Action. Corrective action addresses the cause of an existing non-conformity; preventive action addresses the cause of a potential non-conformity before it occurs. Both are required by ISO 9001:2015 Clause 10.2.
Correction fixes the immediate problem (scrap the bad part). Corrective action removes the cause so it does not recur (fix the calibration process that produced the bad part). Preventive action removes the cause of a potential problem that has not yet occurred (add calibration verification to all similar equipment).
Define an effectiveness verification step at CAPA opening — what will be re-sampled, when, and by whom. At the verification date, re-run the check on a statistically meaningful sample. If the defect has not recurred, close. If it has, reopen and revise root-cause.
Stopping at 'human error' or 'operator training', using 5 Why on multi-factor problems, closing CAPA without effectiveness verification, and confusing containment (immediate fix) with corrective action (systemic fix).
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