SoftwareQualitätssicherung

Software quality refers to the degree to which a software product satisfies stated and implied requirements and meets user needs, while exhibiting desirable attributes under specified conditions. It encompasses functional aspects—what the software does—as well as nonfunctional attributes such as performance, reliability, usability, security, maintainability, and portability. Quality is evaluated against defined requirements, the intended environment, and stakeholder expectations. International standards differentiate product quality from quality in use and prescribe a framework for measuring and improving both.

Quality models have evolved since the early days of software engineering. Notable frameworks include McCall’s quality factors, Boehm’s models, and the ISO/IEC 9126 standard, which was superseded by ISO/IEC 25010. The latter defines eight product quality characteristics: functional suitability, performance efficiency, compatibility, usability, reliability, security, maintainability, and portability. Quality in use describes the user’s perception of quality during real use, considering effectiveness, efficiency, satisfaction, and freedom from risk. Quality requirements guide both development and testing activities.

Software quality assurance encompasses the processes and activities that ensure quality is built into the product. This includes requirements management, design and code reviews, testing, static and dynamic analysis, and ongoing process improvement (for example, through CMMI or ISO 9001). Common quality metrics include defect density, defect leakage, test coverage, code complexity, and mean time between failures. Achieving high software quality involves balancing cost, schedule, and risk, and is typically pursued through systematic planning, verification, validation, and continuous improvement.