Cost Of Quality
Cost of quality represents the total cost of preventing, detecting, and correcting quality problems throughout the software lifecycle.
“The total costs incurred on quality activities and issues and often split into prevention costs, appraisal costs, internal failure costs and external failure costs.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Cost Of Quality?
It includes investments in prevention and appraisal as well as the costs resulting from internal and external failures. Understanding these costs helps organizations improve quality economically.
Prevention costs: Activities that reduce the likelihood of defects.
Failure costs: Expenses caused by defects discovered before or after release.
Business value: Investing in prevention often reduces overall quality costs.
Real World Example
A regulated product team is preparing a release where Cost of quality appears in reviews, test design conversations, or defect triage rather than as an isolated glossary word.
The risk is that the team treats Cost of quality 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 Cost of quality and similar ideas.
The page becomes useful in practice because Cost of quality is connected to a specific testing decision, not memorized as a detached definition.
Practice Questions
Question 1
Which statement BEST describes Cost of quality in the context of ISTQB terminology?
Question 2
A tester needs to explain Cost of quality to a non‑technical stakeholder. Which approach is MOST appropriate?
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