Cause and Effect Analysis: Fishbone Diagram
By: Ray Myers, Jr., PMP
The Fishbone Diagram identifies many possibilities for an effect or a problem. It is an established problem solving tool that is well suited for group analysis because it visually assists with understanding of a problem’s roots cause. Dr. Ishikawa developed the fishbone diagram as an analysis tool that provides a systematic way of looking at effects and the causes that create or contribute to those effects. The Fishbone Diagram may also be referred to as a Cause-and-Effect Diagram or an Ishikawa Diagram in honor of the inventor.
First, let’s define some important terms:
Affect: The action that causes the effect
Effect: The result of the actions of the affect
Fishbone Diagrams are typically developed during a brainstorming session to immediately sort ideas into useful categories. Here’s how to develop a Fishbone Diagram:
Setup
- Prepare a conference room with a white board, flip chart or other means to collect the ideas that are generated by the session
- Nominate a scribe to write the ideas on the white board or flip chart
- Limit group size to 8-10
Process
- The group leader writes the effect (the problem) on the far right side of the whiteboard or flip chart
- Group members brainstorm to identify the major factors or possible causes of the problem
- The scribe groups the causes around related factors and draws arrows on the diagram that shows their relationships
- Explore and probe for contributory causes using the 5 Ws and H: Who, What Why, When, Where and How
Analysis
- After all the causes have been identified, the scribe or group leader should circle the primary causes on the whiteboard
- Group members may gather additional or supporting data as needed to be sure everyone understands the major causes
- Group members rank the causes in order of contribution to the problem
- The team develops solutions based on their analysis
Advantages
- The Fishbone Diagramming process clearly defines the roots causes of a problem before defining solutions
- The resulting diagram also identifies contributing causes
- Focuses the team on the causes that need most attention or change
Disadvantages
- Requires that the problem is clearly identified and understood before analysis
- May become complex if major factors are not broken down into contributing fishbones
About the Author: Ray Myers, Jr. is a PMP certified project manager with over 2o years experience planning and managing technology projects. Contact Ray at wwwpmservicesnw.com
Article source: www.pmservicesnw.com
