Quality Assurance
The ISO 8402 definition of quality was "all those attributes of a product or service that bear upon its ability to satisfy stated or implied needs." This was a serviceable definitions that served us well since the BS 5750 was first published in 1979 and ISO 9001 in 1987. The definition was superseded in ISO 9000 2000 which is subtly different. Quality is now a degree to which a set of inherent characteristics fulfils requirements. A requirement is further defined as a need which is stated, generally implied or obligatory, and implied is defined as 'custom or common practice for an organization, its customers and other interested parties.' Not as pithy a definition, but it is helpful in the way we now think of quality. Because it is no longer sufficient for quality to be defined in terms of an agreed statement of requirements, quality is much more explicitly shaped by the user's perceptions. Quality is now much more about customer satisfaction than about whether the process has delivered what it set out to deliver (in the words of the Chief Executive of Hewlett Packard, "you can get an ISO 9000 certificate for a process for making concrete lifejackets."). No longer. Quality is customer satisfaction. And what about those other interested parties? Might they not be the company's shareholders? Therefore a quality system needs to be appropriate to a company's business needs and still allow the company to make a profit. Quality professionals cannot set unrealistically high standards and therefore be antagonistic to management, they must work in harmony with management to satisfy all the stakeholders, not just customers.

The old definition of quality tended to encourage companies to think of quality as some inherent attribute of the product at hand. This led to another antagonism between delivery staff and the QA function. In project management terms it's referred to as "the trade off triangle. Quality, speed, cheapness. Pick any two. The implication is that quality can be traded off, if the product has to be shipped quickly or produced at very low cost. In removing reference to the product, the characteristics at hand are determined not by a particular product but by the customer and could include things like time and cost. the Quality requirement is what you arrive at after you have done the trade off between what it is preferable to call performance and or function and cost and time and in this sense can never be traded off. However the need to produce a Rolls Royce instead of a more serviceable model is indeed negotiable.

Quality Assurance we can define as something distinct from Quality Control. Quality control are all those mechanisms in use during the design and production of a product ( or delivery of a service) used to ensure the customer's agreed requirement is delivered as intended and includes such activities as inspection, reviewing, checking, testing and so on. Quality Assurance on the other hand are those activities applied to the production system or procedures, or process definitions to ensure that the company's systems are working as intended and therefore is capable of meeting any customer's agreed requirements. Quality assurance consists of the design of processes and measurement systems, the gathering of measurement data, quality audits, and the feed into the management review system. Quality Management is the combination of the two regimes and is rounded off by the management review, as an evaluation of the suitability of the management system for the company.