Suitable might be the most generic term within the Q42 properties.

Being right or appropriate for a particular person, purpose, or situation.

Note: In previous versions of Q42, the term “testable” was used instead of suitable. Users found that to be overly specific, see the discussion here.


(Functional) Suitability:

…provides functions that meet stated and implied needs when used under specified conditions.


The ISO restricts Suitability to functional aspects. In our opinion it is useful in a broader sense: For example, seen from a testing perspective, suitable can mean “easy to test”.

“Responsibility” as alternative term

Bass et. al, 2022 propose to use the term “responsibility” instead of (functional) suitability. That is, from our perspective, a matter of taste.

Typical Acceptance Criteria


What Stakeholders mean by suitable

Stakeholder (potential) Expectation for suitable
User * offers the required (suitable) functions in appropriate quality
* adequate performance
* adequate robustness
* adequate accessibility and useability
Product-Owner * providing appropriate (suitable) functions in suitable quality
* easy to enhance by new functions or features
Management * appropriate cost/benefit ratio
* appropriate effort required to add new features of functions
Developer * appropriate effort required to understand internals
* good code readability
* appropriate effort required to locate and fix bugs
* appropriate technologies used
* appropriate technical documentation
Tester * appropriate effort required for testing
Admin * easy to perform required administration tasks (like deploy, install, configure etc)
Domain-Expert -
Others -

Qualities tagged with #suitable

Requirements tagged with #suitable