Chapter 3 – Static Testing
Defect Density – ISTQB Definition
Last Updated: July 12, 2026 · SoftwareTestPilot QA Team
Official ISTQB Definition
The number of defects identified in a component or system divided by the size of the component or system.
In simple words
How many defects per 1,000 lines of code, page of spec, or story point.
Exam tip
Defect density is a leading indicator — sudden spike often means a component needs refactoring or more testing.
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