Severity
Severity is the degree of impact that a defect has on the operation, functionality, or quality of a software product.
“The degree of impact that a defect has on the development or operation of a component or system.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Severity?
Severity helps assess how seriously a defect affects users or the system, independent of how urgently it should be fixed.
Technical impact: Measures the effect on system behavior.
Independent of priority: Severity and priority are different concepts.
Defect classification: Common levels include critical, major, minor, and trivial.
Real World Example
A regulated product team is preparing a release where Severity appears in reviews, test design conversations, or defect triage rather than as an isolated glossary word.
The risk is that the team treats Severity as interchangeable with nearby ISTQB terms. That makes test scope blurry and can lead to weak evidence for the release decision.
The tester anchors the discussion in the official definition, asks where the concept appears in the product, and designs examples that show the difference between Severity and similar ideas.
The page becomes useful in practice because Severity is connected to a specific testing decision, not memorized as a detached definition.
Practice Questions
Question 1
Which statement BEST describes Severity in the context of ISTQB terminology?
Question 2
A tester needs to explain Severity to a non‑technical stakeholder. Which approach is MOST appropriate?
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