Software Quality Attributes

The quality of software systems may be expressed as a collection of Software Quality Attributes. When the system requirements are defined, it is essential also to define what is expected regarding these quality attributes, since these expectations will guide the planning of the system architecture and design.

Software quality attributes may be classified into two main categories: static and dynamic. Static quality attributes are the ones that reflect the system’s structure and organization. Examples of static attributes are coupling, cohesion, complexity, maintainability and extensibility. Dynamic attributes are the ones that reflect the behavior of the system during its execution. Examples of dynamic attributes are memory usage, latency, throughput, scalability, robustness and fault-tolerance.

Following the definitions of expectations regarding the quality attributes, it is essential to devise ways to measure them and verify that the implemented system satisfies the requirements. Some static attributes may be measured through static code analysis tools, while others require effective design and code reviews. The measuring and verification of dynamic attributes requires the usage of special non-functional testing tools such as profilers and simulators.

In this talk I will discuss the main Software Quality attributes, both static and dynamic, examples of requirements, and practical guidelines on how to measure and verify these attributes.