Failure
A failure is an event in which a component or system does not perform a required function within specified limits during execution.
“An event in which a component or system does not meet its requirements within specified limits.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Failure?
Failures are observable during software execution and are often caused by one or more underlying defects in the software or environment.
Visible behavior: Failures are experienced by users or testers during execution.
Relationship to defects: A defect may cause a failure when executed under specific conditions.
Investigation: Failures trigger analysis to identify their root cause.
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 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 helps everyone discuss the problem using a shared testing vocabulary.
Practice Questions
Question 1
Which statement BEST describes Failure in the context of ISTQB terminology?
Question 2
A tester needs to explain Failure to a non‑technical stakeholder. Which approach is MOST appropriate?
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