Quality assurance (QA) is the activity of providing evidence needed to establish confidence among all concerned, that quality-related activities are being performed effectively. All those planned or systematic actions necessary to provide adequate confidence that a product or service will satisfy given requirements for quality.
QA covers all activities from design, development, production, installation, servicing to documentation. It introduced the sayings "fit for purpose" and "do it right the first time". It includes the regulation of the quality of raw materials, assemblies, products and components; services related to production; and management, production, and inspection processes.