Defect detection percentage (DDP) is a type of testing metric. It indicates the effectiveness of a testing process by measuring the ratio of defects discovered before the release and reported after the release by customers.
For example, let’s say, the QA has detected 70 defects during the testing cycle and the customer reported 20 more after the release. Then, DDP would be: 70/(70 + 20) = 72.1%
