D5 (Choose and Verify Permanent Corrective Actions)

8D discipline where the team selects the best Permanent Corrective Action (PCA) to eliminate root causes identified in D4. Must address both the creation cause (why defect occurred) and escape point (why it wasn't detected). Solutions are tested on small scale before full implementation to verify effectiveness without creating new problems. Uses risk assessment (FMEA) to evaluate potential unintended consequences. Similar to A3 Countermeasures but with more explicit verification requirements before rollout.