As quality attributes are non-functional requirements and functionality is typically out of scope for quality models (as obviously it is measured against acceptance criteria and therefore can be evaluated precisely), I wonder about the following problems, which to me seems inconsistent with this:
- Can software quality be evaluated based on functional requirements only? One could say that mere functionality does not mean that a product is quality or not, on the other hand, if the functionality provides the fitness for purpose...
- When we test software and find functional defects, we say the quality is bad. Technically speaking, a defect in functionality is not a quality characteristic.