Failure Mode
A failure mode is the specific way in which a component or system fails to perform its intended function.
“The physical or functional manifestation of a failure.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Failure Mode?
Identifying failure modes helps teams understand potential system weaknesses and design tests that verify how failures are detected and handled.
Failure description: Defines how the failure appears or behaves.
Risk analysis: Different failure modes have different business impacts.
Testing value: Test cases can target known failure modes.
Real World Example
A hospital medication system shows a different dosage warning in test than the one specified by the clinical safety rule.
The team needs precise language to separate what was observed, what should have happened, and whether the difference represents a reportable issue. Failure mode provides that distinction.
The tester records the steps, data, observed behavior, expected behavior, and evidence so triage can focus on patient safety impact instead of vague descriptions.
The issue is handled faster because Failure mode helps everyone discuss the problem using a shared testing vocabulary.
Practice Questions
Question 1
Which statement BEST describes Failure mode in the context of ISTQB terminology?
Question 2
A tester needs to explain Failure mode to a non‑technical stakeholder. Which approach is MOST appropriate?
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