Baseline performance, DPU, DPO, DPMO, and yield

Learning objectives

• Compute DPU, DPO, DPMO and first-pass yield.
• Distinguish defective units from defects.
• Choose defensible opportunity counts.

Baseline formulas

• DPU = defects ÷ units.
• DPO = defects ÷ (units × opportunities per unit).
• DPMO = DPO × 1,000,000.
• First-Pass Yield = units passing without rework ÷ units processed.

Assumptions and interpretation

Opportunities must be defensible — inflating them lowers DPMO artificially. Rolled Throughput Yield multiplies step yields only when steps are independent.

Defects per unit and defective-unit rate differ whenever a garment can carry multiple defects.

Garment-factory example

500 polos with 80 recorded seam defects give DPU = 0.16. If each polo has 8 defensible opportunities, DPO = 80 / (500×8) = 0.02 and DPMO = 20,000. The defective-unit rate is a separate count of garments with at least one defect.

Method

1. Freeze the unit, defect and opportunity definitions.
2. Count consistently across the study window.
3. Report FPY separately from post-repair yield.
4. State assumptions and rework rule.

Common mistakes

• Inflating opportunities to lower DPMO.
• Reporting final yield after repair as first-pass yield.