Cause-and-Effect Diagram
Also Known As
Ishikawa Diagram
Fishbone Diagram
Examples
Roberts L, Johnson C, Shanmugam R, et al. Computer simulation and six-sigma tools applied to process improvement in an emergency department. 17th Annual Society for Health Systems Management Engineering Forum; 2005; Dallas, TX; 2005.
McCray M. How to get paid for the services you provide. 2007 Society for Health Systems Conference; 2007; New Orleans, LA; 2007.
Description
Cause-and-effect diagrams provide a visual means of conveying all suspected and possible causes and consequences of a specific problem.
Uses
To identify sources of process variation.
To investigate a detrimental effect and determine causes so they can be corrected.
To serve as a "cause-prevention" tool by evaluating how to avoid future problems.
To investigate a positive effect and determine which causes allowed it to occur.
How do I use this tool?
1. ASSEMBLE A SUITABLE GROUP of individuals who have requisite knowledge of the area under analysis.
2. CLEARLY DESCRIBE THE EFFECT for which causes are needed.
3. DRAW THE EFFECT at the end of a large arrow. Leave enough room to add the generated causes.
4. IDENTIFY THE MAIN CATEGORIES of possible causes of the effect. Make branches originating from the large arrow and add the categories to the branches.
5. BRAINSTORM ALL POSSIBLE CAUSES and put them in the appropriate portion of the chart. Descriptions should be brief and to the point. Go through the chart category by category. Any causes that would belong to multiple categories should be placed under all relevant categories. It may be necessary to redraw the chart.
6. ANALYZE THE IDENTIFIED CAUSES to determine which will require further analysis. Bear in mind the primary goal is to solve the problem rather than eliminate the symptoms.
Expertise Required
This tool is easy to use and requires little or no training.
Recommended Supplies/Materials
Flip chart
Advantages
Exposes limitations of existing knowledge.
Can visually display a great number of causes in a reasonable size.
Identifies many of the causes of a problem.
Disadvantages
The outcome requires a good leader and participation of process owners who fully understand the problem under consideration.
Where can I go to learn more?
George M, Rowlands D, Price M, et al. Identifying and verifying causes. The lean six sigma pocket toolbook. New York: McGraw - Hill; 2005. p. 141-96.
University Research Company LLC. Health care improvement project: cause-and-effect analysis. 2008 [cited 2009 July 28];
American Society for Quality. Cause analysis tools: fishbone diagram. 2009 [cited 2009 June 26]; Available from: http://www.asq.org/learn-about-quality/cause-analysis-tools/overview/fishbone.html