I rate this tool a 2/5, along with DPMO and DPO. The reason is that I like to keep things simple, and metrics like this tend to lose audiences during project reviews. People ask, “What does that calculation really mean?” I prefer readily-understandable metrics like cost, PPM defect rate, and yield percentage. Customers do not care about DPU, DPO, and DPMO.
These metrics were popular when Six Sigma was developed, but I haven’t seen them used much since that time.
The training slide below shows how to calculate DPU, which stands for Defects Per Unit (see example to the right as well).