All conservatism is based upon the idea that if you leave things alone, you leave them as they are. But you do not. If you leave a thing alone, you leave it to a torrent of change.
(G. K. Chesterton, 1908)
A process is defined internationally as a set of interacting activities that turn inputs into outputs (ISO 9000, ANSI/ISO/ASQ, 2005). But in Chapter 9 we saw that there is no such thing as a perfect process and there will always be variation in the key characteristics of the output of any process as a result of special and common causes. Some of that variation will not conform to requirements. We need a way to ensure that stable and capable processes remain so through self‐correction. Stability provides consistency in output characteristics. Capability provides cost‐effective results. System self‐correction reduces or eliminates nonconformity in product or service through a system of controls.
Controls are essential to diverse professions, each with its ...