Defect-based Test Technique
A defect-based test technique designs test cases using knowledge of known defect types, historical failures, or common programming mistakes.
“A test technique in which test cases are developed from what is known about a specific defect type.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Defect-based Test Technique?
Instead of relying only on specifications, testers use previous defect patterns and experience to target areas where defects are most likely to occur.
Knowledge-driven: Historical defect data guides test design.
Experience: Previous project lessons improve future testing effectiveness.
Risk reduction: Frequently defective areas receive additional testing attention.
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. Defect-based test technique 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 Defect-based test technique helps everyone discuss the problem using a shared testing vocabulary.
Practice Questions
Question 1
Which statement BEST describes Defect-based test technique in the context of ISTQB terminology?
Question 2
A tester needs to explain Defect-based test technique to a non‑technical stakeholder. Which approach is MOST appropriate?
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