The fishbone diagram was designed by Japanese quality control expert Kaoru Ishikawa. His purpose was to provide a means of identifying underlying causes of problems so that solutions were not misapplied to secondary causes; if underlying causes are missed, larger problems develop. The fishbone diagram is meant to detect root causes of problems through group thinking by asking why each potential cause happens. The fishbone diagram is traditionally worked from right to left with "bones" for each cause branching from the center bone. The complexity of the fishbone lies in the smaller branching bones supporting each potential cause and answering "why" (whatis.techtarget.com).
Major advantages to the fishbone diagram accord with the purpose and method of the fishbone.
- It identifies cause and effect relationships in problems.
- The method operates through the function of joint brainstorming discussions.
- Brainstorming allows for broad-ranging thinking, steering teams away from "in a rut" thinking patterns.
- These diagrams ask "why does this happen" again and again at each stage as each potential cause is identified.
- Fishbone allows for prioritizing relevant causes so the predominating, underlying root cause is addressed first.
Some major disadvantages relate to the greatest strengths of the fishbone diagram.
- Brainstorming produces irrelevant potential causes along with relevant ones, resulting in a time and energy drain.
- Brainstorming is as often based on opinion as on fact and evidence (fishbonediagram.org)
- A very large space for working out the diagram is needed for complex problems with many branching bones and "why"-bones.
- The complex interrelationships of multiple factors are difficult to show on a fishbone (worldbank.org).
Here is an illustration of a detailed fishbone diagram.
An excellent tool for brainstorming in all fields of study, the "fish bone" diagram is a graphic organizer used to analyze cause and effect.
Since causes and effects are not always simple, their ramifications and origins are studied using the diagram. Doing this helps to extrapolate the real causative factors that lead to an event to take place. Similarly, the consequences of such event are also isolated and categorized if needed.
Another benefit is that, from understanding these factors, you can get to solutions faster especially if you are studying the organizer as a team.
The fishbone starts by stating the problem in the form of a question. This is what goes at the beginning of the chart, where the fish's "head" would be.The best way is to make it into a "why" question
Business - Why are our sales decreasing?
Education- Why did only 30% of my students pass the last test?
Marketing- Why did so many people like the last bubble gum campaign?
These are examples of questions that help move the discussion forward into the rest of the chart.
While there are no disadvantages in using a graphic organizer per se, the appropriate use of it is what makes it worth while. Moreover, the fishbone works best when it is completed by a team. If the team does not agree on the central "why" question, or if the "why" question is not the question that should be analyzed, then the organizer will never really solve any problems.
The major advantage of a fishbone diagram (also known as an Ishikawa diagram) is that it can be of great help in a situation where a person or team of people is trying to determine the cause of some problem. The major advantage is that a fishbone diagram helps the team by providing a convenient and easily understood way of thinking of and listing possible causes of the problem that is being faced. The team comes up with basic sources of possible problems (like machines, work methods, or measurement) and then brainstorms, trying to think of what aspects of these sources could possibly be causing the problem.
The major disadvantage is simply that it doesn't solve any problems. It can only help in identifying possible causes of problems and does not offer any possible solutions or any analysis of the likelihood that a given cause is the real one. In addition, it is not very good at pointing out which of the possible causes is most likely or most important. Graphically speaking, it makes all possible causes look equally plausible and equally important.