Root Cause
A root cause is the underlying reason why a defect, failure, or problem occurred.
“A source of a defect such that if it is removed, the occurrence of the defect type is decreased or removed.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Root Cause?
Addressing the root cause helps prevent the same issue from recurring instead of repeatedly fixing only its symptoms.
Underlying issue: Root causes explain why problems occur.
Problem prevention: Eliminating root causes reduces recurrence.
Improvement focus: Supports better processes and product quality.
Real World Example
A regulated product team is preparing a release where Root cause appears in reviews, test design conversations, or defect triage rather than as an isolated glossary word.
The risk is that the team treats Root cause 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 Root cause and similar ideas.
The page becomes useful in practice because Root cause is connected to a specific testing decision, not memorized as a detached definition.
Practice Questions
Question 1
Which statement BEST describes Root cause in the context of ISTQB terminology?
Question 2
A tester needs to explain Root cause to a non‑technical stakeholder. Which approach is MOST appropriate?
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