What is ISO standard for non-functional requirements?

The International Organization for Standardization (ISO) has developed several standards that relate to non-functional requirements for software systems. One of the key standards relevant to non-functional requirements is ISO/IEC 25010:2011, which is part of the ISO/IEC 25000 series, also known as SQuaRE (Software Product Quality Requirements and Evaluation).

ISO/IEC 25010:2011

This standard provides a comprehensive model for software product quality and specifies eight quality characteristics, each of which contains sub-characteristics. These are essential for defining, measuring, and evaluating non-functional requirements of a software product. The eight main characteristics are:

1. Functional Suitability

   • This characteristic assesses whether the software meets the functional requirements. It is about the presence and completeness of functions that fulfill specified needs.

2. Performance Efficiency

   • This evaluates the performance relative to the amount of resources used under stated conditions. Sub-characteristics include time behavior, resource utilization, and capacity.

3. Compatibility

   • This assesses the co-existence of the product with other independent products and its ability to interact with them. It includes interoperability and compatibility with other systems.

4. Usability

   • This measures the extent to which the product can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction. It includes user interface aesthetics, accessibility, and consistency of the user interface.

5. Reliability

   • This assesses the capability of the software to maintain a specified level of performance when used under specified conditions. It includes maturity, fault tolerance, recoverability, and availability.

6. Security

   • This characteristic assesses the software’s ability to protect information and data so that unauthorized persons or systems cannot read or modify them and authorized actions are not denied. It includes confidentiality, integrity, non-repudiation, accountability, and authenticity.

7. Maintainability

   • This refers to the ease with which a software product can be modified to correct faults, improve performance or other attributes, or adapt to a changed environment. Sub-characteristics include modularity, reusability, analyzability, modifiability, and testability.

8. Portability

   • This measures the ease with which the software product can be transferred from one environment to another. This includes adaptability, installability, co-existence, and replaceability.

Applying ISO/IEC 25010:2011

When defining non-functional requirements for a project, using the ISO/IEC 25010 standard can help ensure a comprehensive approach to product quality. It provides a framework that facilitates clear communication about quality requirements and evaluation criteria between stakeholders, developers, and evaluators. This standard can guide the development process to focus on critical areas that contribute to the overall quality and satisfaction of the final software product.

Conclusion

The ISO/IEC 25010:2011 standard provides a robust framework for understanding, defining, and measuring non-functional requirements in software development. It helps ensure that software products are developed to high standards of quality across multiple dimensions, enhancing user satisfaction and product performance. By integrating these standards into the development process, organizations can deliver software products that are not only functionally robust but also perform well across various quality characteristics.