Cause & Effect Diagram
Originally developed by Kaoru Ishikawa to visualize the causes of a specific event,
the Cause and Effect Diagram has come to be known by several names: Cause and Effect,
Fishbone, or Ishikawa diagram. It is one of the seven basic Quality control tools,
and has become commonly used to determine components needed for a desired outcome.
The main issue is written in a box that is typically in the center of the right edge
of the page. A line called the "spine" or "backbone" extends to the left starting
from the edge of the main box. Branches angle off of the spine, each representing
a cause or effect of the main issue. Each of these branches may contain additional
branches.
Typical Uses
A Cause and Effect Diagram is used to examine why something happened or might happen
by breaking up the issue into smaller categories. It can also be helpful to show
relationships between contributing factors.
Best Practices
- Identify the process or event. Define the process or issue to be examined.
- Draw the backbone. Once the topic is identified, draw a straight, horizontal line (this is called the spine or backbone) on the page, and on the right side, draw a rectangle at the end. Write a brief description of the topic in the rectangle.
- Add branches. Draw a line starting on the backbone and extend it away from the backbone at an angle away from the main process rectangle. Either perpendicular or parallel to the spine, write a description of a cause or effect at the end of the branch. Details related to the cause or effect may branch off from the branch touching the spine. Continue to add branches and a cause or effect until all factors have been documented. The end result should resemble a fish skeleton.
- Analyze. Once the diagram has been completed, analyze the information as it has been organized in order to come to a solution.