Cause and effect diagrams, sometimes known as "fish- bone analysis" from the form of the diagram produced, are a valuable way of illustrating the apparent relationships which could exist between the separate causes of a problem, and therefore they assist in isolating them for closer examination.
These diagrams are produced in four main stages, illustrated in Figure 5:
(1) Establish what the problem is.
(2) Identify the apparent prime causes.
(3) Isolate salient subdivisions of the prime causes. (4) Identify possible linkage factors between them.
A frequent problem in creating these diagrams is that they are drawn to a small scale initially; the identification of contributory factors therefore becomes confused, and difficult to follow and interpret — draw it large!