Workflow · D5 · The D-steps
D5 — Verify effectiveness
D5 is where 8Ds are usually strongest or weakest. Verification is either done seriously — with a defined observation window, a defined metric and production data — or it is a formality that gets the report closed and the problem reopened.
Key takeaways
- Pick a metric that will change if the fix works — usually defect rate, escape rate or process capability.
- Set the observation window in advance (number of shifts, lots or units).
- Report weekly, not just at the end.
- If the metric does not improve, return to D4 — do not force closure.
Define the acceptance criterion
- Metric — defect rate, escape rate, first-pass yield, capability index.
- Threshold — the value that means "verified".
- Window — number of shifts, lots or units of continuous production.
- Sample plan — how the metric will be measured.
Verification methods
- Production run monitoring against the metric.
- Increased sampling on the affected feature during the observation window.
- Customer field data (returns, complaints) over the window.
Handoff to D6
D5 verifies the fix on the affected process; D6 implements the fix across the wider system (all lines, all cavities, all similar processes) and locks it in.
Common mistakes
- Verifying with a single lot when the defect frequency demands weeks.
- Using the same test that failed to detect the defect in the first place.
- Closing the 8D before the observation window ends.
In the Qhubio 8D workspace
How Qhubio handles verification
Qhubio requires a defined verification plan before the D5 phase can be approved and links verification evidence directly to the report.
- Verification plan captured before the observation window starts.
- Evidence linked at D5 (production data, sampling records).
- Phase-gated approval before D6 can be advanced.
Frequently asked questions
- How long should the verification window be?
- Long enough to see the defect reappear if the fix does not work. For rare defects this can be weeks; for high-frequency defects, days.
- Can we use lab test results for verification?
- Lab tests are a supporting input, not a substitute for production observation. Most customers expect production data.
- What if the fix partially works?
- Return to D4. A partial fix usually means the root cause was misidentified.
Related guides
The D-steps
D4 — Identify and verify root cause
D4 identifies and proves the root cause and escape cause. Learn how to move from candidate causes to proven root cause in 8D.
The D-steps
D8 — Closure and lessons learned
D8 closes the 8D formally — customer sign-off, lessons learned, PFMEA and control plan updates, team recognition.
The D-steps
D2 — Containment action
D2 containment stops defective product from reaching the customer while the investigation runs. Learn how to scope, verify and communicate containment.
Methods & pitfalls
Common 8D mistakes
The recurring reasons 8Ds get rejected, reopened or drift — weak D3, unproven root cause, missing escape cause, superficial verification.
Run this D-step inside a structured workspace
Qhubio is a structured 8D workspace: evidence-grounded phases, phase-gated approvals and audit-ready exports.