Fishbone diagrams, or cause and effect diagrams, were developed for quality control issues by Kaoru Ishikawa. They have several benefits and some drawbacks. Al of which will be covered in the following article. Decide how complex the issue being discussed can become and what outcome you want before settling on the best root cause analysis. Fishbone diagrams are good for fleshing out problems that have not been explored in the past and you need different ideas to get to the root cause.
Identify the Problem
The first step or the head of the diagram should be the exact problem you face. If possible write down who was involved, what time it occurred and specifically explain the whole problem. This allows people to focus on specifics and not a generic idea or too broad of a subject.
Major Factors Involved
This step involves identifying the major factors of the problem. There are several options to use her, but make sure they are appropriate to the issue. These could be systems, process, equipment, people or external factors. Gather as many of these as possible and make them the large ¡°bones¡± of the diagram. These are the cues that the group will use for the next stage.
Identify All Possible Causes
This is the production stage of the fishbone. Have the group brainstorm possible causes and write them down under the major factors that they are most closely associated. Withhold any judgement you may have on ideas being offered. Let the group open up and capture everything that is offered. It may be that an unidentified cause may appear that wouldn¡¯t have if the group was restrained by rules or judgement.
Analyse Your Diagram for Exact Causes
The diagram should be filled with an abundant amount of likely causes and some not so likely causes. Using the group to accept or deny possible causes, narrow the list to the best 2 or 3 and investigate those possibilities further. It may take time to pursue each cause and break it down to its root. Split your group into smaller groups and give them one of the likely causes. Have them research their cause and make a case for how likely it is to be the exact cause of the issue. If the group is small, have them research each idea independently.
Conclusion and Limitations
After the group reconvenes, have them discuss each cause and pick the best one for this issue. Have them identify root causes and then build systems to prevent the issue from reoccurring. A limitation of the fishbone diagram is that if the problem is too complex or interrelated then the fishbone diagram isn't the best tool to use, also the cause and effect diagram dosn't necessarily deal in facts, it can have opinion and supposition as elements of the skeleton. So be aware of its limitations as you decide which method of discovery is best. The fishbone diagram can be an excellent tool for focusing a group and finding root causes to any number of issues and problems.