Defects per million opportunities equals total defects divided by (units inspected times opportunities per unit), times one million. Ten defects found in 500 boards with 20 solder joints each gives 10 divided by 10,000, or 1,000 DPMO. Normalizing by opportunities lets a simple part and a complex assembly be compared, but the opportunity count is a judgment call and can be inflated to flatter the number.
Joint-level DPMO dropped to 85 after the stencil change, but board-level fallout barely moved.
Also heard as
- defects per million opportunities
Related terms
Sigma level
Process quality expressed as the number of standard deviations that fit between the mean and the nearest spec limit.
Yield
Fraction of units that come out good at a step or across a whole process, the headline number for any production line.
1.5 sigma shift
Six Sigma convention that assumes a process mean wanders by 1.5 standard deviations over the long term.
Defect density
Number of yield-killing defects per unit area of wafer or panel, the main input to yield models.