Modifiability
Modifiability is the degree to which a software product can be changed efficiently without introducing defects or degrading existing quality.
“The degree to which a component or system can be modified without degrading its quality.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Modifiability?
Highly modifiable software is easier to enhance, adapt, or correct because its design minimizes unnecessary complexity and dependencies.
Ease of change: Modifications require minimal effort.
Low impact: Changes should affect as few components as possible.
Quality support: Good architecture improves long-term maintainability.
Real World Example
A regulated product team is preparing a release where Modifiability appears in reviews, test design conversations, or defect triage rather than as an isolated glossary word.
The risk is that the team treats Modifiability 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 Modifiability and similar ideas.
The page becomes useful in practice because Modifiability is connected to a specific testing decision, not memorized as a detached definition.
Practice Questions
Question 1
Which statement BEST describes Modifiability in the context of ISTQB terminology?
Question 2
A tester needs to explain Modifiability to a non‑technical stakeholder. Which approach is MOST appropriate?
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