Chapter 5 – Test Management
Defect Detection Percentage (DDP) – ISTQB Definition
Last Updated: July 12, 2026 · SoftwareTestPilot QA Team
Official ISTQB Definition
The number of defects found by a test level, divided by the total number found by that level and any other means afterwards.
In simple words
What share of eventual bugs did this test level catch? Higher is better.
Exam tip
DDP is a leading indicator of how effective your test level really is.
Related terms
Practice this term in the ISTQB Mock Test
40 CTFL v4.0 questions, 60-minute timer, instant scoring and chapter-wise breakdown.
Practice in Mock Test