Fishbone Diagram

FISHBONE DIAGRAM

Overview

The Fishbone Diagram is a traditional cause-and-effect diagram, designed to identify all possible causes of a single problem or “effect”. The causes can then be systematically investigated. 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 (Brussee, 2004).

A diagram resembling the skeleton of a fish that is used to identify and categorize the possible causes of problems. Within a fishbone chart, the topic or problem to be discussed is placed in a box at the right-hand side that corresponds to the fish's head, and the major elements to be investigated are shown as branches at an angle to the horizontal spine. Questions are asked to identify possible causes of problems in each area and the results are added to the diagram as additional layers of branches. This ensures that all aspects of the problem are considered systematically.

A diagram that is used to identify and categorize the possible causes of problems. Within such a chart, which resembles the shape of the skeleton of a fish, the topic or problem to be discussed is placed in a box at the right-hand side that corresponds to the fish's head, and the major items to be investigated are shown as branches at an angle to the horizontal spine. Questions are asked to identify possible causes of problems in each area and the results are added to the diagram as additional layers of branches. This ensures that all aspects of the problem are considered systematically. The fishbone chart is also known as a cause and effect diagram. It is frequently used in brainstorming and problem solving (Fryman, 2002).

Example of a Fishbone Diagram

Approach

Name the problem or “effect”. Place the name in a box on the right hand side of the chart.

Draw a long horizontal arrow pointing to the box. Include an arrow going into the problem to illustrate that the “causes” have an influence on the “effect”.

Name the major categories of causes. These can be pre-determined or developed through a ...