Internal Failure
An internal failure is a failure detected before the software is released to customers, typically during development or testing.
“A failure that occurs during the operation of a system before its delivery to the end users.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Internal Failure?
Internal failures allow defects to be corrected before reaching production, reducing business impact and correction costs.
Detected before release: Found during reviews, testing, or internal use.
Lower cost: Fixing internal failures is generally less expensive than fixing external failures.
Quality improvement: Early detection improves product quality.
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. Internal 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 Internal failure helps everyone discuss the problem using a shared testing vocabulary.
Practice Questions
Question 1
Which statement BEST describes Internal failure in the context of ISTQB terminology?
Question 2
A tester needs to explain Internal failure to a non‑technical stakeholder. Which approach is MOST appropriate?
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