4.6 Planning & Managing Quality
Key Takeaways
- Quality is defined as the degree to which a set of inherent characteristics fulfills requirements - it is about meeting requirements, not exceeding them
- Cost of Quality (COQ) includes Cost of Conformance (prevention and appraisal) and Cost of Nonconformance (internal and external failure costs)
- The 7 Basic Quality Tools are: cause-and-effect diagrams, flowcharts, check sheets, Pareto diagrams, histograms, control charts, and scatter diagrams
- Prevention costs (training, planning) are less expensive than appraisal costs (testing, inspection), which are less expensive than failure costs (rework, warranties)
- Quality management follows the principle: plan quality into the project rather than inspect it in
Quality management is about ensuring the project produces deliverables that meet requirements and satisfy stakeholder expectations. The focus is on prevention rather than inspection - building quality in rather than inspecting defects out.
Quality Management Processes
| Process | Purpose | Key Output |
|---|---|---|
| Plan Quality Management | Identify quality requirements and standards | Quality Management Plan |
| Manage Quality | Translate quality plan into executable activities | Quality Reports |
| Control Quality | Monitor and record quality results | Verified Deliverables |
Quality vs. Grade
| Concept | Definition | Example |
|---|---|---|
| Quality | Degree to which characteristics fulfill requirements | A product works as specified |
| Grade | Category assigned based on functional use | Business class vs. economy class |
- Low quality is always a problem (defects, rework, customer dissatisfaction)
- Low grade may be acceptable (a basic product that works as designed)
Cost of Quality (COQ)
Cost of Quality = Cost of Conformance + Cost of Nonconformance
Cost of Conformance (Good Money)
Investment to prevent failures from occurring:
| Category | Description | Examples |
|---|---|---|
| Prevention Costs | Preventing defects before they occur | Training, planning, process documentation, equipment |
| Appraisal Costs | Evaluating products for quality | Testing, inspection, audits, quality reviews |
Cost of Nonconformance (Bad Money)
Costs incurred due to failures:
| Category | Description | Examples |
|---|---|---|
| Internal Failure Costs | Defects found before delivery | Rework, scrap, re-testing |
| External Failure Costs | Defects found by customer | Warranties, returns, lawsuits, lost reputation |
COQ Principle
Prevention is cheaper than inspection, which is cheaper than failure.
LEAST COSTLY MOST COSTLY
↓ ↓
Prevention → Appraisal → Internal Failure → External Failure
COQ Example
| Category | Amount | % of Total |
|---|---|---|
| Prevention | $50,000 | 10% |
| Appraisal | $100,000 | 20% |
| Internal Failure | $150,000 | 30% |
| External Failure | $200,000 | 40% |
| Total COQ | $500,000 | 100% |
The goal is to shift spending toward prevention to reduce overall COQ.
Quality Management Plan
The Quality Management Plan describes how quality policies will be implemented:
| Component | Description |
|---|---|
| Quality Standards | Standards and regulations to follow |
| Quality Objectives | Measurable quality goals |
| Quality Roles | Responsibilities for quality activities |
| Deliverables Subject to Review | What will be inspected or tested |
| Quality Control Activities | How quality will be verified |
| Quality Tools | Techniques and tools to be used |
The 7 Basic Quality Tools
These tools, originally proposed by Dr. Kaoru Ishikawa, are fundamental for quality management:
1. Cause-and-Effect Diagrams (Fishbone/Ishikawa)
Identifies potential causes of problems:
- Structure: Problem at the "head," major categories as "bones"
- Categories: Often use 6Ms - Manpower, Methods, Materials, Machines, Measurement, Mother Nature (Environment)
- Purpose: Root cause analysis using "5 Whys"
2. Flowcharts
Shows process steps and decision points:
- Purpose: Visualize processes, identify waste or problems
- Use: Process improvement, documentation
3. Check Sheets (Tally Sheets)
Structured form for collecting data:
- Purpose: Collect data consistently
- Use: Defect tracking, frequency analysis
4. Pareto Diagrams (80/20 Rule)
Bar chart showing problems in descending order:
- Principle: 80% of effects come from 20% of causes
- Purpose: Prioritize problems to address first
- Use: Focus improvement efforts on biggest issues
5. Histograms
Bar chart showing distribution of data:
- Purpose: Visualize data patterns and variation
- Shows: Central tendency, dispersion, shape of distribution
6. Control Charts
Monitor process stability over time:
| Element | Purpose |
|---|---|
| Center Line | Mean or target value |
| Upper Control Limit (UCL) | +3 standard deviations |
| Lower Control Limit (LCL) | -3 standard deviations |
Rule of Seven: 7 consecutive points on one side of the mean (but within limits) indicates the process is out of control.
7. Scatter Diagrams
Plot two variables to show correlation:
- Purpose: Identify relationships between variables
- Shows: Positive, negative, or no correlation
Additional Quality Tools
Design of Experiments (DOE)
Statistical method for identifying optimal conditions:
- Tests multiple variables simultaneously
- Identifies which factors most affect results
- More efficient than one-at-a-time testing
Statistical Sampling
Inspecting a subset rather than 100% of items:
| Sampling Type | Description |
|---|---|
| Attribute Sampling | Conforming/not conforming (pass/fail) |
| Variable Sampling | Measuring on a continuous scale |
Quality Metrics
Quality Metrics define what will be measured and how:
| Metric Type | Example |
|---|---|
| Defect Rate | Number of defects per 1000 units |
| Customer Satisfaction | Survey score (1-10 scale) |
| Process Compliance | % of processes followed correctly |
| Rework Rate | % of work requiring rework |
| On-Time Delivery | % of deliverables delivered on time |
Manage Quality vs. Control Quality
| Manage Quality | Control Quality |
|---|---|
| Translates plans into executable activities | Monitors and records quality results |
| Process-focused | Product-focused |
| Audits and process analysis | Inspection and testing |
| Continuous improvement | Verification of deliverables |
| Proactive | Reactive |
Quality Principles
Key Quality Concepts
| Principle | Description |
|---|---|
| Customer Satisfaction | Meet customer requirements |
| Prevention over Inspection | Build quality in, don't inspect it in |
| Continuous Improvement | Kaizen - always seeking to improve |
| Management Responsibility | Leadership must support quality |
| Cost of Quality | Invest in prevention to reduce total cost |
Quality Gurus and Concepts
| Guru | Key Concept |
|---|---|
| Deming | Plan-Do-Check-Act (PDCA), 14 Points |
| Juran | Quality Trilogy (Planning, Control, Improvement) |
| Crosby | Zero Defects, Quality is Free |
| Ishikawa | 7 Basic Quality Tools |
Key Takeaways
- Quality is meeting requirements, not exceeding them
- Cost of Quality = Conformance + Nonconformance costs
- Prevention is cheaper than inspection or fixing failures
- The 7 Basic Quality Tools are essential for quality management
- Manage Quality is proactive; Control Quality is reactive
- Quality should be planned and built in, not inspected in
A project manager invests in training team members on quality standards before development begins. This is an example of which Cost of Quality category?
A control chart shows seven consecutive data points above the mean but within the control limits. This indicates:
Which quality tool would be MOST useful for prioritizing defects to address first based on their frequency of occurrence?