Cause and Effect Diagram

Cause & Effect is a diagram-based technique that helps you identify all of the likely causes of the problems you're facing.

What is it?

A visual display that includes:

  • The name of the problem stated a way that does not pre-judge its causes.
  • Major cause areas / categories for the causes of the problem, for example materials, processes, people, environment and equipment
  • The reasons and root causes associated with each category / cause area
  • Possible solutions for each root cause
  • A cause and effect diagram is sometimes called a fishbone diagram after its resemblance to the bones of a fish or an Ishikawa diagram after its creator
What does this tool look like?
Example of Cause & Effect Diagram
Why use this tool?
  • To allow a team to explore the possible reasons, root causes and possible solutions for a problem
  • To visually represent the reasons, root causes and possible solutions for a problem
  • To help identify change ideas and develop an improvement plan
  • To enable team to focus on content of the problem, not on the history or differing personal interests. 
Where does this tool fit in the improvement journey?
Where this tool fits in the improvement journey
How to use it

Tips for Facilitation:

  • Agree the problem statement and where possible include the what, where, when and how much of the problem. Use data to specify the problem.
  • Give the problem a name that avoids pre-judging the cause(s). On flipchart paper write the name in the problem statement in a box (fish head) on the right-hand side of the paper. Draw bones of the fish.
  • Go where the problem arises and gather facts, not opinions about the problem.
  • Brainstorm the reasons. Write them individually on yellow post-its.
  • From the post-its agree the major cause areas / categories the team should focus their thinking on. Write each of these at the end of a fishbone (e.g. people, materials, methods, machines).
  • Place each of the yellow post-its to the left of the appropriate bone. Sometimes this will spark more discussion where further ideas are generated.
  • For each effect on the post-its ask the “5 Whys?” and continue to do so to determine the true root cause of the problem. If there is disagreement about the root cause gather more facts.
  • Use pink post-its to record the agreed root causes. Place them beside the relevant yellow post-its. 
  • When complete take a photograph of the Fishbone and /or type it up to allow all team members to reflect on it for agreement.
  • Use this to develop an improvement plan. Guide the team to prioritisation of improvements based on ease of implementation and impact.
Resources to download