What is the purpose of corrective action in QC and how is effectiveness verified?

• A. To adjust acceptance criteria after every failure
• B. To replace faulty equipment without investigation
• C. To document nonconformities but not verify
• D. To address root causes of nonconformities; verify by re-testing and reviewing subsequent data to ensure issue is resolved

Answer: (D)

Corrective action in QC focuses on eliminating the root cause of a nonconformity and proving that the fix actually works. When a nonconformity is found, the goal is to investigate and identify why it happened, implement a change that prevents recurrence, and then confirm effectiveness. Verification is done by re-testing the affected process or product and by reviewing subsequent data to ensure results are now conforming and that no new issues have emerged. This closes the loop: you don’t just fix the symptom, you prove that the problem is resolved.

Why the other approaches aren’t adequate: simply adjusting acceptance criteria after every failure can raise thresholds to pass despite problems, rather than solving them. Replacing equipment without investigation may address a symptom without addressing the underlying cause, risking recurrence or unnecessary downtime. Documenting nonconformities without verification leaves you without evidence that the corrective action actually worked.