A cause and effect diagram often called a ‘fishbone’ diagram, can help in brainstorming to identify root causes of a problem and in sorting ideas into useful categories. This article describes how it can be created and explains it’s advantages.
Root cause analysis is a team process that can help to identify underlying factors or causes of an event. Understanding the contributing factors of an issue can help develop actions to prevent it from happening again. Developed by Professor Kaoru Ishikawa of the University of Tokyo, the main aim of the fishbone technique is to help to identify and list all the possible causes that have brought about a problem.
How to use the Fishbone Technique
Define your problem. Try to be specific; problems that are too large can overcomplicate matters, and cause issues in defining the causes. Try to avoid describing the problem in term of the solution e.g. “We need more of x”. Write the problem on the far right or left-hand side of your diagram and draw a long horizontal arrow pointing towards it. This is the mouth of the ‘fish’.
From the horizontal arrow, you will be able to branch off major and minor causes of this problem. First, you must identify the most significant causes or potential causes of the problem. These will form the main branches of the backbone arrow. You may start with quite a few. Continue to brainstorm and define about 6-8 categories. You should be asking yourself “Why does this happen?” to keep digging down into the actual root causes of the problem.
From these, you can continue to brainstorm in more detail, and explore why these factors may be problems. It is best to develop as many suggestions as possible so that no potential root cause is overlooked.
Advantages of the Fishbone Technique
1. It encourages members of a team to study every angle of a problem before making a hasty decision as to what is wrong
2. It helps show the relationship and relative importance of parts of a problem – a point that is often overlooked by people attempting to solve problems in a systematic way
3. It helps establish a logical sequence for handling various parts of a problem in a systematic way
4. It stops a situation where people concentrate all their attention on one cause or part of a problem and are oblivious to the total picture
5. It forces a group to explore everything possible, so there is not further excuse for delay
6. It offers an opportunity to explore a problem from a total approach perspective
7. It often helps to produce solutions without having to proceed to the next stages of the whole cycle
8. Used in group discussion it keeps everyone on track, it brings every relevant factor out into the open and prevents anyone stampeding the group into half-baked decisions
Here is an example of a complete Fishbone Diagram;-