8D and CAPA are both corrective-action frameworks, but they serve different purposes. Here is how they differ, where they overlap, and how to satisfy both without duplicating work.
Side by side
8D
A problem-solving method with fixed disciplines (D0–D8), built for cross-functional investigation of a specific failure. Common in automotive and manufacturing.
CAPA
A quality-system process (Corrective and Preventive Action) that tracks nonconformities, actions, owners and effectiveness over time. Required by ISO 9001 and IATF 16949.
How to choose
Use 8D when the customer demands a structured investigation, or when the cause is unknown.
Use CAPA as the system of record: every 8D becomes one or more CAPA entries.
Investigate once: run the 8D, then link its D5–D7 into the CAPA record instead of writing the case twice.
Close the loop with effectiveness evidence — audits look for verification, not for paperwork.
