Ishikawa diagram
From Free net encyclopedia
The Ishikawa diagram is a graphical method for finding the most likely causes for an undesired effect. The method was first used by Kaoru Ishikawa in the 1960s.
Because of its shape, it is also known as the fishbone diagram. Another name for this technique is: the cause-and-effect diagram. The fishbone diagram is a method/tool used in a root cause analysis.
The Ishikawa diagram is one of the seven basic tools of quality control, which include the histogram, Pareto chart, check sheet, control chart, cause-and-effect diagram, flowchart, and scatter diagram. See Quality Management Glossary.
How to make the diagram
Image:IshikawaCause,Effect.jpg Take a sheet of paper and draw a box on the right side of the paper. Draw a horizontal line from the left side of the box to the right. Write in the box the effect for which you want to find the causes. Starting from the horizontal line, draw four to six short diagonal lines in the direction the left upper and left lower corner of the paper. These are the main bones of the diagram. Label them with categories you know will span the whole problem space. For example, a business may use: management, manpower, machines and materials (the 4 M's).
Next, start filling the diagram with causes. Put them as arrows pointing to any of the main bones of the diagram. After you feel you have named most causes, identify the most likely causes for the effect in the box on the right side.