Facilitator guide
Case objectives, demonstration plans, debriefs, common mistakes and application checks across all 81 workplace cases and method lessons.
Download Facilitator guide PDF · 166 pages · 65.1 MBStop the recurring leak
8D + cause verification. Follow the visual, practise a decision, then check your thinking.
Fictional teaching examples and AI-generated illustrations. Proposed changes and goals are not achieved results. Use the written instructions and check local conditions before applying a method.
Contain the leak; verify the cause
The existing sample has 144 first-test failures in 2400 valves. Begin by defining the affected product, defect and observation period. Temporary containment limits exposure while the team investigates both why the leak occurred and why the process failed to prevent or detect it earlier. Keep possible causes separate from confirmed causes. The proposed 1.5% goal is not a result. Carry a verified corrective action into normal work and review recurrence before retiring containment.
Follow the method
- D0-2: prepare, team, define
- D3: contain exposure
- D4: occurrence + escape
- D5-6: choose, test, validate
- D7-8: prevent recurrence, recognize
Read the example carefully
D0 prepares the work where used. D1 forms the team; D2 defines the problem; D3 contains exposure; D4 verifies occurrence and escape causes; D5 selects and tests permanent action; D6 implements and validates; D7 prevents recurrence; D8 recognizes the team.
Containment protects while investigation continues. Correcting affected units and removing a verified cause are different actions.
Try it before revealing the answer
A fixture association is visible. Is that enough to select permanent corrective action?
Reveal the answer and reasoning
No. Use it to select a discriminating test; preserve containment while checking the cause and the detection gap.
Turn a plausible explanation into a cause test
Write the predicted result before running a controlled comparison. Specify what stays comparable, how failures will be measured, and what result would challenge the explanation. The retained pilot gate of no more than 4 first-test failures in 300 and later validation gate of no more than 36 in 2400 are separate planned checks, not proof already obtained. A small pass alone does not establish long-term performance.
Follow the method
- Observation
- Hypothesis + prediction
- Controlled comparison
- Contrary evidence
- Decision + next test
Read the example carefully
Fixture A: 110 failures / 1,200 tested = 9.17%; fixture B: 34 / 1,200 = 2.83% (rounded). Material, operator and time differences may confound this association.
Teardown categories: rolled seal 82; low torque indication 34; other or undetermined 28. Total 144. Categories and rates guide investigation, not a causal conclusion.
The planned pilot gate is ≤4 / 300; the later validation gate is ≤36 / 2,400. No future results have been supplied.
Try it before revealing the answer
What is the difference between relabelling or repairing affected units and changing the cause?
Reveal the answer and reasoning
The first corrects those units; corrective action changes a verified cause and requires an effectiveness check.
Sources and further reading
- ASQ — Eight Disciplines 8D ↗
8D progresses through team formation, problem definition, containment, verified occurrence and escape causes, permanent correction selection, effectiveness validation, recurrence prevention and team recognition; some organizations add D0 preparation.
Brainstorming does not verify a cause; interim containment is distinct from permanent corrective action. - ASQ — Fishbone Diagram ↗
Fishbone diagrams organize possible explanations into categories to support exploration and further analysis.
A diagram branch is a candidate explanation, not automatically a verified cause. - ASQ — Handbook of Corrective and Preventive Action, Sample ↗
Correction resolves a detected nonconformity, such as through repair or rework; corrective action addresses its causes to prevent recurrence.
The handbook sometimes groups correction and containment; a three-way teaching distinction should be identified as an explicit convention.
Take the lesson into your team.
Read the lessons online or use these PDFs to prepare, practise and review with your team. No sign-in needed.
Learner workbook
Printable case worksheets, blank observation records and five calculation exercises; answers are separate.
Download Learner workbook PDF · 169 pages · 10.7 MBAnswer key and coaching notes
Reasoned sample responses, worked calculations and coaching guidance; fictional examples are clearly labelled.
Download Answer key and coaching notes PDF · 105 pages · 8.5 MBMethod and application reference
The native method mechanisms and worked applications for all 68 detailed lessons, in a separate bookmarked portrait reference.
Download Method and application reference PDF · 141 pages · 10.2 MBIllustrated systems atlas
Five illustrated system chapters: 15 Flare concept maps and 26 original workplace teaching cards, with links to all 81 supporting cases and method lessons.
Download Illustrated systems atlas PDF · 69 pages · 55.8 MBUse the next tool for the next question.
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- PDCA in cafe
- Daily-management escalation in construction
Make the welding bay ready to work
A verified occurrence or escape cause can lead to a prevention or detection change at the work station.
Explore the connected method →Make tomorrow ready
Daily follow-up keeps containment, response owners and effectiveness checks visible after the investigation.
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