ISO/IEC 9126 - Quality in Use Metrics

Quality in Use Metrics

Quality in use metrics are only available when the final product is used in real conditions.

Ideally, the internal quality determines the external quality and external quality determines quality in use.

This standard stems from the GE model for describing software quality, presented in 1977 by McCall et al., which is organized around three types of Quality Characteristics:

• Factors (To specify): They describe the external view of the software, as viewed by the users.
• Criteria (To build): They describe the internal view of the software, as seen by the developer.
• Metrics (To control): They are defined and used to provide a scale and method for measurement.

ISO/IEC 9126 distinguishes between a defect and a nonconformity, a defect being The nonfulfilment of intended usage requirements, whereas a nonconformity is The nonfulfilment of specified requirements. A similar distinction is made between validation and verification, known as V&V in the testing trade.