Cause and Effect Diagram
Everything has its causes. There are many options to capture a problem's causes. One effective way to sort these different ideas and stimulate the team's brainstorming on root causes is the cause and effect diagram, also known as fishbone diagram.
What Cause and Effect Diagram Is
Cause and Effect Diagrams are also known as Fishbone Diagrams, Ishikawa Diagrams, Herringbone Diagrams, and Fishikawa Diagrams. They are causal diagrams created by Kaoru Ishikawa (1968) that show the causes of a specific event. Refer to the following example for better understanding. This diagram is created by Edraw, an all-in-one diagramming tool.
When to Use Cause and Effect Diagram
The Fishbone diagram could be applied when it is wanted to:
- Focus attention on the causes of one specific issue or problem.
- Focus the team on the causes rather than the symptoms.
- Organize and demonstrate visually the various theories about what the root causes of a problem may be.
- Show the relationship of various factors contributing to a problem.
- Reveal important relationships among various variables and possible causes.
- Provide additional insight into process behaviors.
- Display the sequence of related factors.
- Present the incidence of certain elements.
Prerequisites or Limitations of Cause and Effect Diagram
- The problem is composed of a limited number of causes, which are in turn composed of sub causes.
- Distinguishing these causes and sub causes is a useful step to deal with the problem.
How to Construct Cause and Effect Diagram
When you construct a Cause-and-Effect Diagram, you are building a structured, graphic display of a list of causes organized to show their relationship to a specific result. Notice that the diagram has a cause side and an effect side. The steps for analyzing and diagramming a Cause-and-Effect process are outlined below.
Step 1 - Identify and clearly define the outcome or EFFECT to be analyzed. This is also the problem to be solved or the purpose of analysis.
Step 2 - Prepare the SPINE and EFFECT box. Traditionally, this is drawn on hand. Nowadays, there is a more advanced tool with ready-made cause and effect diagram templates. Users only need to drag and drop templates with such tool like Edraw.Step 3 - Find out the main CAUSES contributing to the object being studied. These are the labels for the major branches of your diagram and become categories under which to list the many causes related to those categories. You had better use category labels that make sense for the diagram you are making, such as 3Ms and P methods - materials, machinery, and people.
Step 4 - For each major branch, list other specific factors which may be the CAUSES of the EFFECT.
Step 5 - Identify increasingly more detailed levels of causes and continue organizing them under related causes or categories. You can do this by brainstorm. NOTE: You may need to divide your diagram into smaller diagrams if one branch has too many subbranches. Use a hyperlink to connect another diagram. Any main cause (3Ms and P, 4Ps, or a category you have named) can be regarded as an effect.
Step 6 - Analyze the diagram. Analysis helps you identify causes that warrant further investigation. By analyzing, you figure out the relationship and then find out better strategy or solution.
Learn how to make a fishbone diagram here.