Why this decision matters
Every operations failure of the last decade had a quality story underneath it. Boeing's 737 MAX, Tesla's paint defects, the formula recall — each of them was a control chart that nobody read, a root cause that nobody chased, or a DMAIC cycle nobody ran. Quality isn't a department; it's a habit of seeing variation, asking why, and standardizing the answer. This is the most "career-transferable" decision in the course — Six Sigma rigor reads the same in a bakery, a hospital, and a bank.
By the end of this topic you'll be able to
Run the DMAIC cycle on a small operational problem. Use the Seven Tools fluently (flowchart, check sheet, Pareto, fishbone, scatter, histogram, control chart). Construct an X-bar/R or p-chart, read it for special-cause signals, and compute Cp/Cpk. Calculate cost of quality (prevention + appraisal + internal failure + external failure) and use it to defend an investment.
Materials
Key concepts to know
- DMAIC — Define, Measure, Analyze, Improve, Control. The improvement cycle.
- Seven Tools — flowchart, check sheet, Pareto, cause-and-effect (fishbone), scatter, histogram, control chart.
- 5 Whys — keep asking "why" until you reach a root cause you can act on.
- 5S — Sort, Set in order, Shine, Standardize, Sustain. Workplace organization.
- Poka-yoke — mistake-proofing. Make the wrong thing impossible.
- Cost of quality — prevention + appraisal + internal failure + external failure. Most companies overspend on appraisal and underspend on prevention.
- Common vs. special cause — common is the system itself; special is something unusual. Different fixes.
- Control charts — X-bar/R for variables, p- and c-charts for attributes. Centerline ± 3σ control limits.
- Run rules — the additional patterns (eight points one side of centerline, etc.) that signal out-of-control without exceeding the limits.
- Cp / Cpk — capability indices. Cp = (USL−LSL)/(6σ); Cpk also penalizes off-center. ≥1.33 is industry minimum, ≥2.0 is Six Sigma.
Slides & lecture decks
- Ch 12 — Quality Management (with AI)TQM, DMAIC, the Seven Tools, cost of quality — with AI examples woven in.
- Ch 13 — Statistical Quality Control (with AI)Control charts, Cp/Cpk, run rules — with AI-augmented monitoring examples.
Bedtime stories — quality through narrative
Long-form stories that teach the quality material through characters. Most people remember Luna's bakery longer than they remember Chapter 12. Each is available as a printable docx and an interactive web version.
- The Midnight Bakery — Part 1: A Lean Six Sigma Fairy Tale (docx)DMAIC, the Seven Friends, TIMWOOD, 5S, poka-yoke — told as a fairy tale.
- The Midnight Bakery — Part 1 (interactive)Same story, browser-friendly with inline concept spotlights.
- The Midnight Bakery — Part 2: The Night Watchers (docx)Control charts and Cp/Cpk as midnight guardians watching every batch.
- The Midnight Bakery — Part 2 (interactive)SPC and Cp/Cpk explored interactively.
Real-industry quality cases (Banking & Manufacturing)
Two case studies that apply Ch 12 & Ch 13 thinking to industries with very different quality cultures. Worth doing both for contrast.
- Banking Quality — Ch 12 & Ch 13DMAIC and SPC in a service-and-compliance setting.
- Manufacturing Quality — Ch 12 & Ch 13DMAIC and SPC on a real production line.
Business Process Analysis (BPA) toolkit
BPA is the consulting cousin of Six Sigma — same goals, faster cycle, less statistical machinery. Useful when you need to improve a process but you're not running a 6-month Black Belt project.
- BPA vs. Six Sigma — how to chooseWhen to reach for which method.
- BPA Consulting ToolkitThe frameworks a working consultant pulls out for a process-improvement engagement.
Hands-on activity — SPC, cost of quality, data matching
- SnackCraft SPC Start FileBuild an X-bar/R chart end-to-end on a snack-packaging line.
- Tesla Cost-of-Quality Start FileClassify spending into prevention / appraisal / failure and recommend a shift.
- Quality Data Matching — StarterMatch defect patterns to the right tool from the Seven.
- Quality Data Matching — Solution KeyCheck your answers after a full pass at the starter.
- Healthcare Diabetes PreventionApply quality thinking to a healthcare-intervention dataset.
Practice with games · Quality & DMAIC
- Six Sigma DetectiveIdentify what kind of variation you're looking at.
- Quality Guru ChallengeMatch the principle to the right quality thinker (Deming, Juran, Crosby...).
- Process Flow Detective — VA vs. NVATag every step as value-add or waste.
- Quality ToolkitsMixed practice across the Seven Tools.
- Quality QuestA guided quest through the chapter.
- DMAIC Business SimulationRun a small turnaround through Define→Control.
- Root Cause Roulette5-Whys drilling against random defect scenarios.
Practice with games · Statistical Process Control
- Control Chart SimulationBuild a chart sample by sample — see signals appear in real time.
- SPC SlowdownIdentify out-of-control patterns under time pressure.
- Variation Station — SPC LabInteractive variation lab; play with shifts and drifts.
- Reading Control ChartsPattern-recognition drill for the run rules.
- Ch 12 & Ch 13 ReviewCombined Q&A drilling.
Using AI on this decision
AI is the most-changed area in quality management right now. Three concrete uses worth trying:
- Triage. Paste a defect log and ask the AI to Pareto it by category and propose a fishbone.
- Real-time control. Run summary statistics through the AI and let it flag suspected special-cause patterns (always verify by chart).
- Root cause. Walk the AI through a 5-Whys conversation, then push back when it stops at "human error."
Three interactive companions:
- AI Triage CenterAI-augmented quality triage.
- Process Rescue GameUse AI to rescue a failing process.
- AI & Lean Six Sigma — SuiteCurated set of AI-augmented quality activities.
Self-check (Part 3 review — covers Topics 6 & 7)
The same Part 3 self-check appears on the Topic 7 page too — either entry point is fine. Choose docx or interactive game format.
- Part 3 Study Guide (docx)Comprehensive review of Decisions 6 & 7.
- Practice A (docx)
- Practice B (docx)
- Part 3 Study Guide (interactive)Browser version with concept spotlights.
- Part 3 Practice (interactive)Self-check questions with feedback.
- Part 3 JeopardyGame-show format for retrieval practice.