In the context of software engineering, software quality refers to two related but distinct notions that exist wherever quality is defined in a business context:

Structural quality is evaluated through the analysis of the software inner structure, its source code, in effect how its architecture adheres to sound principles of software architecture. In contrast, functional quality is typically enforced and measured through software testing.

Historically, the structure, classification and terminology of attributes and metrics applicable to software quality management have been derived or extracted from the ISO 9126-3 and the subsequent ISO 25000:2005 quality model, also known as SQuaRE.^{[citation needed]} Based on these models, the software structural quality characteristics have been clearly defined by the Consortium for IT Software Quality (CISQ), an independent organization founded by the Software Engineering Institute (SEI) at Carnegie Mellon University, and the Object Management Group (OMG).