Cause & Effect Diagrams

A Cause & Effect Diagram (sometimes referred to as a Fishbone Diagram) is used to categorize and organize ideas about contributing factors and their relationships within a process.

Use a Cause & Effect Diagram to: 

• Define and understand the causes of an outcome
• Graphically display the relationship of causes to the outcome
• Help identify improvement opportunities

 See an example here.

1. Start by drawing a central horizontal line with a box at one end. Write the specific process or outcome being studied in the box.
2. Next, draw four to six vertical lines from the horizontal line; these will identify classes of contributors (sources) to the central issue. Frequent classes include People, Equipment, Environment, Methods, and Materials. These may be supplemented by other sources identified by the team.
3. Generate a list of factors or situations that ‘cause’ a problem and assign them to one of the identified sources. The Cause & Effect Diagram can be completed by either working entirely through all of the causes in one source before moving on to the next or moving randomly from source to source as items are identified.
4. Look for multiple causes within a single source. As questions such as:
    

• What is being done? 
• Why (cause) is it done at all? 
• What else could be done in its place to accomplish the same result?
• When is it done? 
• Why (cause) is it done at that time? 
• Is there another time it could be done?
• Who does it? 
• Why (cause) these specific individuals?
• Could someone else do it?
• Whehttp://dev2.rsna.org/WorkArea/edit.aspxre is it done?
• Why (cause) is it done there?
• Where else could it be done?
• How is it done?
• Why (cause) is it done that way?
• Are there other ways it could be accomplished?

Continue to analyze the situation until the causes of the problem are specific enough that a potential change can be identified. Then seek consensus on the likely few causes that if ‘fixed’ would improve the process.