Threshold Coverage
Threshold coverage is a coverage criterion that measures whether specified threshold values or limits have been exercised during testing.
“The coverage of neurons exceeding a threshold activation value in a neural network for a set of tests.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Threshold Coverage?
Testing threshold values helps verify correct behavior at critical operational limits and decision boundaries.
Boundary focused: Tests values around defined thresholds.
Coverage measurement: Tracks tested threshold conditions.
Real World Example
A tax calculation module applies different deductions depending on income band, residency status, and submitted documents.
Reviewing the final tax amount is not enough when important code paths may never execute during testing. Threshold coverage helps the tester reason about the structure behind the result.
The tester works with the developer to identify decisions or paths in the calculation logic and designs inputs that exercise the meaningful alternatives.
The team gains better evidence about hidden logic because Threshold coverage connects tests to the implementation structure where certain defects can hide.
Practice Questions
Question 1
Which statement BEST describes Threshold coverage in the context of ISTQB terminology?
Question 2
A tester needs to explain Threshold coverage to a non‑technical stakeholder. Which approach is MOST appropriate?
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