Fish Bone or Ishikawa Diagram

The fishbone diagram or Ishikawa diagram (named after Dr. Kaoru Ishikawa ) is a diagram that resembles a fishbone, or rather a fish skeleton that is viewed from the side. The main purpose of the fishbone diagram is to show what will cause a specific event. What will be caused relates to both primary and secondary causes for a specific event, so the diagram can help all eventualities be considered.


History of the Fishbone Diagram

The First fishbone diagrams were used by the Japanese "guru" inthe 1960's and soon afterwards everyone in quality management was using it to consider cause and effect.  It is considered one of the most fundamental tools in management today.  


How a Ishikawa Diagram works

The diagram works by an event being placed on the ‘backbone’ of the fish and then lines from there, show the primary causes and secondary causes.  So to analyse a basic problem such as ‘no electricity’ the problem would be highlighted on the backbone and all primary and secondary causes will be identified.  No electricity could be caused by not paying the bill, by the utility company being inefficient, by building works that are being undertaken etc.

Once completed it provides a pictorial assessment of our problem and potential route causes.  Thus the cause and effect of this diagram.


Fishbone Diagrams as brainstorming Tools


The fishbone diagram forces you to think along logical lines, in other words, to take an issue and think about it until you have thought about every single result that could happen.

The process of forecasting can be helpful because it sorts out the relationship between cause and effect and helps all those involved understand that each action or event has a consequence i.e you look at the causes and they drive a certain event to happen. Fishbone diagrams are great when coupled with 5 why analysis.  It can also be used with a negative and positive aspect (2 point system) for any decision making process.  

These are only a few ideas for the Fishbone Diagram.