Metrics that express how your product or process is performing. Choosing the appropriate quality metric helps you assess performance against customer expectations. You can also develop project baselines and improvement goals, as well as communicate the level of conformance to your customers.
Defects per unit (DPU) is the number of defects in a sample divided by the number of units sampled.
For example, your printing business prints custom stationary orders. Each order is considered a unit. Fifty orders are randomly selected and inspected and the following defects are found.
Six of the orders have problems and there are a total of 7 defects out of the 50 orders sampled; therefore DPU = 7/50 = 0.14.
On average, this is your quality level and each unit of product on average contains this number of defects.
Defects per opportunity (DPO) is the number of defects in a sample divided by the total number of defect opportunities.
For example, each custom stationary order could have four defects - incorrect, typo, damaged, or incomplete. So each order has four opportunities. Fifty orders are randomly selected and inspected and the following defects are found.
Six of the orders have problems and there are a total of 7 defects out of the 200 opportunities (50 units * 4 opportunities / unit); therefore DPO = 7/200 = 0.035.
Defects per million opportunities (DPMO) is the number of defects in a sample divided by the total number of defect opportunities multiplied by 1 million. DPMO relates the customer's pain at the opportunity level and is useful because you can compare processes with different complexities.
For example, each custom stationary order could have four defects - incorrect, typo, damaged, or incomplete. So each order has four opportunities. Fifty orders are randomly selected and inspected and the following defects are found.
There are a total of 7 defects out of the 200 opportunities; therefore DPO = 0.035 and DPMO = 0.035 * 1000000 = 35000. If your process remains at this defect rate over the time it would take to produce 1,000,000 orders, you would have generated 35000 defects.