Measure
The Measure phase establishes a reliable baseline of current performance using trustworthy data. Green Belts learn to classify data, compute core defect metrics, and confirm that the measurement system itself is accurate before drawing conclusions.
Defect metrics: DPU, DPO, DPMO
Defects Per Unit (DPU) equals total defects divided by total units. Defects Per Opportunity (DPO) divides defects by units times opportunities, and DPMO scales DPO by one million. These metrics let teams compare processes of different complexity on a common basis.
Sigma level and yield
Process sigma expresses how many standard deviations fit between the process center and the nearest specification limit, commonly reported with a 1.5-sigma long-term shift. On that scale about 66,807 DPMO is roughly three sigma and about 3.4 DPMO is six sigma.
Measurement System Analysis
Gage Repeatability and Reproducibility (Gage R&R) quantifies how much observed variation comes from the measurement system rather than the product. Repeatability is variation from one appraiser repeating a measurement; reproducibility is variation between different appraisers.