Non-functional requirements

In our roles as system architects, developers, or project managers, we often face a broader scope of requirements than the long list of functional change requests provided at the outset. Among these, non-functional requirements frequently present the greatest challenges. These requirements, often unwritten, remain implicit expectations from stakeholders. Statements like “Of course, the system should be user-friendly” or “Naturally, it must meet performance needs for the next decade” highlight these assumptions. Such conversations underline a critical question: what is quality?

Defining quality extends beyond functionality. Non-functional attributes, such as usability, scalability, and legal compliance, play a pivotal role in shaping a system’s success. Stakeholders might assume these qualities, but they require explicit identification and prioritization to avoid gaps in understanding. For example, regulatory compliance, like adhering to a country’s legal standards, is essential but often overlooked in specifications. Addressing these attributes proactively ensures no critical aspect is left to chance.

To tackle this, IT Informa has developed a comprehensive model and process for defining and managing quality. This approach integrates both functional and non-functional quality attributes, ensuring each one is clearly defined, prioritized, owned, and verified. This structured method minimizes ambiguities and aligns stakeholders and teams around shared quality standards.

Non-functional requirements, in particular, drive the architecture process during application development. They shape decisions on system performance, reliability, and scalability, ensuring the architecture meets present and future needs. Similarly, they influence the test strategy. By identifying all quality attributes early, teams can select the right tools, define necessary skills, and plan activities that ensure quality throughout the project lifecycle.

Through a structured approach to quality, teams can better align expectations, mitigate risks, and deliver systems that meet both functional and non-functional demands. Prioritizing and verifying these requirements ensures stakeholders’ expectations are met, fostering trust and long-term system success. By addressing the question of what is quality, IT Informa empowers teams to deliver robust, high-performing solutions.