Very few individuals can differentiate between quality control and quality assurance. Most quality assurance groups, in fact, practice quality control. This section differentiates between the two, and describes how to recognize a control practice from an assurance practice.
Quality means meeting requirements and meeting customer needs, which means a defect-free product from both the producer’s and the customer’s viewpoint. Both quality control and quality assurance are used to make quality happen. Of the two, quality assurance is the more important.
Quality is an attribute of a product. A product is something produced, such as a requirement document, test data, source code, load module or terminal screen. Another type of product is a service that is performed, such as meetings with customers, help desk activities and training sessions. Services are a form of products, and therefore, also contain attributes. For example, an agenda might be a quality attribute of a meeting.
A process is the set of activities that is performed to produce a product. Quality is achieved through processes. Processes have the advantage of being able to replicate a product time and time again. Even in data processing, the process is able to replicate similar products with the same quality characteristics.
Quality Assurance (QA) is associated with a process. Once processes are consistent, they can "assure" that the same level of quality will be incorporated into each product produced by that process.
Quality Control (QC) is defined as the processes and methods used to compare product quality to requirements and applicable standards, and the action taken when a nonconformance is detected. QC uses reviews and testing to focus on the detection and correction of defects before shipment of products.
