In its broadest sense, quality is a degree of excellence: the extent to which something is fit for its purpose. In the narrow sense, product or service quality is defined as conformance with requirement, freedom form defects or contamination, or simply a degree of customer satisfaction. These are some of the definitions which are often quoted and any of which may be true in certain circumstances.
Quality has different meanings depending on the product and also to different people. The concept of Quality on anything, may it be a product or service has to do with psychological expectation of the users/consumers towards performance or achievements of the desired results. Against this background there must be knowledge of the expected results against some benchmark.
All those planned and systematic action necessary to provide adequate confidence that a product or service will satisfy given requirements for quality. As defined in ISO 9001:2000 it is part of quality management system focused on providing confidence that quality requirements will be fulfilled.
Quality is the result of a comparison between what was required and what was provided. It is judged not by the producer but by the receiver. The judgment can be made of an intention, as is the case when selecting suppliers, or an output, as is the case when purchasing a product or service.
The only true measure of acceptable quality is customer satisfaction, which takes into account both objective and subjective interpretations of the needs and expectations of customers. If customers are satisfied with the products and services offered, the organization has not only correctly interpreted customer needs and expectations but it is also providing products and services of acceptable quality.