Quality Assurance is defined as all the planned and systematic activities implemented within the quality system and demonstrated as needed, to provide adequate confidence that an entity will fulfil requirements for quality.
An entity can be an activity, a process, a product, an organization, a system or a person or a combination of these. The quality of an entity is the totality of characteristics which bear on its ability to satisfy stated and implied needs. This means that QA is all the activities that have been shown to be required to provide adequate confidence that a product or service will meet both the stated and implied needs of the product or service and these activities are implemented in a planned and controlled manner.