The Fishbone Diagram

A Visual Technique for Problem Solving

The Fishbone Diagram (developed in Japan by Professor Ishikawa) can be used by individuals, but is most effective when used by a group. The technique structures the problem solving process and analyzes possible causes. The process encourages indepth analyzes and objectivity from all the participants in the session. It creates solid grounds for mature decisions and successful solutions.
It shows the inter-connections and relationships between different parts of a problem.

Here is the fishbone diagram in six steps.

Clarify the objectives of the session.
Draw a straight line with a box at one end. Inside the box write the problem/issue to be considered (This is the head and spine of the fish) .
For every reason or factor contributing to the issue draw in a stem coming off the spine. Brainstorm participants to identify causes or reasons or factors at the end of the stem.
Take each stem one at a time, examine the causes and add in branches representing sub-causes that are contributing to the issue. Each sub-cause analyzes Why the issue/problem occurs. Highlight each sub-cause that occurs more than once. It may be significant.
The group should now discuss each stem and its branches in order to identity the main aspects.
Rank the causes in order of priority and discuss about each.