What is a fish bone diagram ?

Dr. Kaoru Ishikawa, invented the fishbone diagram. Therefore, it can be also referred as Ishikawa diagram.
Fishbone diagram is an analysis diagram which provides a systematic way of looking at effects and the causes that create or contribute to those effects. Because of the function of the fishbone diagram, it may be referred to as a cause-and-effect diagram. The design of the diagram looks much like the skeleton of a fish. Therefore, it is often referred to as the fishbone diagram.
Fishbone diagram helps in categorizing potential causes of problems or issues in an orderly way and in identifying root causes.
Below is a sample fish bone diagram which shows why a project dead line was not met. The middle arrow is the main problem “Deadline not met”. Then we start analyzing other problems which has led to this problem.Example There is client problem -- as he is always changing the requirement -- this is caused because the company did not sign the SRS --- and this happened as proper project management procedures where not at place. So to solve this problem we either appoint a project manager or give training on project management to senior team members.