Critical To Quality Metrics (CTQ)

Variation and The Normal Curve

Defect Opportunities:
- Number of places a defect can occur in a product, process or service.
DPMO
- Defects per million opportunities
- Example:
  - Small assemblies/processes = fewer opportunities
    - Pen: 5 opportunities
      - Cap doesn’t fit,
      - Color incorrect
      - Ink leaks
  - Complex assemblies/processes = greater opportunities.
    - Laptop: 1000+ opportunities
      - Keys stick
      - Display color wrong
      - Power Supply
      - Bad Ram
      - HDD
      - OS Corruption
      - and on and on
DPO
- Defects per Opportunity
- Total number of defects / Total number of Defect Opportunities
- Far more accurate than Defects Per Unit!
Ex:
- Production reports 2 defects per unit for both Pens and Laptops
  - Pen: 1000 units * 2 defects per unit = 2000 total defects
  - Laptop: 1000 units * 2 defects per unit = 2000 total defects
- Pen:
  - DPO = 2000 / (1000* 5) = 0.4 DPO
  - DPMO = 1,000,000 * 0.4 = 400,000 DPMO
- Laptop
  - DPO = 2000 / (1000 * 1000) = 0.002 DPO
  - DPMO = 1,000,000 * 0.002 = 2,000 DPMO