fishbone chart

Technique, Japanese in origin, designed to assess the causes of problems in a quality circle. The attempt to identify the possible causes of a problem requires drawing a diagram working back from the problem. These causes fall into four main categories, known as the four Ms: men; methods; machines; and materials. There are four steps to the process: identifying the problem; identifying the possible causes within the main categories; identifying possible detailed causes; and drawing the causes on the diagram for discussion.