Functional Correctness
Functional correctness is the degree to which software provides correct results with the required level of precision for specified tasks.
“The degree to which a component or system provides the correct results with the needed degree of precision.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Functional Correctness?
It evaluates whether implemented functions behave according to requirements and produce accurate outputs under expected conditions.
Correct behavior: Functions should produce expected outcomes.
Accuracy: Outputs should be complete and precise.
Testing focus: Functional tests compare actual and expected results.
Real World Example
A regulated product team is preparing a release where Functional correctness appears in reviews, test design conversations, or defect triage rather than as an isolated glossary word.
The risk is that the team treats Functional correctness 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 Functional correctness and similar ideas.
The page becomes useful in practice because Functional correctness is connected to a specific testing decision, not memorized as a detached definition.
Practice Questions
Question 1
Which statement BEST describes Functional correctness in the context of ISTQB terminology?
Question 2
A tester needs to explain Functional correctness to a non‑technical stakeholder. Which approach is MOST appropriate?
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