Root Cause analysis is a technique to identify the root cause of risk, defect so that solutions can be devised to reduce or eliminate them.
1. The Fishbone Diagram
A fishbone diagram (also known as an Ishikawa or cause-and-effect diagram) is used to identify and organize the possible causes of a problem. This tool helps to focus on the cause of the problem and find the solution and ideas, and also organizing the ideas for further analysis. The diagram serves as a map that depicts possible cause-and effect relationships.
Steps to develop a fishbone diagram include:
Step 1. Capturing the issue or problem under discussion in a box at the top of the diagram.
Step 2. Drawing a line from the box across the paper or whiteboard (forming the spine of the fishbone).
Step 3. Drawing diagonal lines from the spine to represent categories of potential causes of the problem. The categories may include people, processes, tools, and policies.
Step 4. Drawing smaller lines to represent deeper causes.
Step 5. Brainstorming categories and potential causes of the problem and capturing them under the appropriate category.
Step 6. Analysing the results. Remember that the group has identified only potential causes of the problem. Further analysis is needed to validate the actual cause.
Step 7. Brainstorming potential solutions once the actual cause has been identified.
2. The Five Whys
The five whys is a question asking process to explore the nature and cause of a problem. The five whys approach repeatedly asks questions in an attempt to get to the root cause of the problem. This is one of the simplest facilitation tools to use when problems have a human interaction component.
To use this technique:
Step 1. Write the problem on a flip chart or whiteboard.
Step 2. Ask “Why do you think this problem occurs?” and capture the idea below the problem.
Step 3. Ask “Why?” again and note that idea after the first idea.
Repeat step 3 again and again until you identify the root cause. This may take more or less than five questions—the technique is called the five whys because it often takes that many to reach the root cause, not because the question must be asked five times.
The five whys can be used alone or as part of the fishbone diagram technique. Once all ideas are captured in the diagram, use the five whys approach to drill down to the root causes.