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Cause & Effect Analysis (Fishbone Diagrams)

Cause & Effect diagrams (also called Fishbone or Ishakawa diagrams) were developed in the 1950ís by Ishakawa, the Japanese Statistician, for use by Quality Circles which he also developed.

They are a structured and visual brainstorming tool designed to help a team to identify all the possible causes of the problem that they are trying to solve. When completed, they provide a Map of the problem and are particularly useful in the first two meetings of a team when they are embarking on their diagnostic journey.


A local office in a government department found that papers and articles (scientific ones) took months to circulate to all the people on the circulation list. In a one hour session, an action team brainstormed possible reasons and causes and created the following fishbone. A voting exercise highlighted three items as being the main causes and they then went on to tackle and resolve them.

example cause and effect fishbone analysis

The general procedure is:

Step 1 - An initial Brainstorm of 20 or so possible causes of the problem.
Step 2 - Draw your first Fishbone
Step 3 - Brainstorm further onto the Fishbone
Step 4 - Vote & Prioritise
Step 5 - Action Plan

Brainstorming | Rating & Ranking | Fishbone Analysis | Process Mapping | Pareto Analysis | Mind Mapping | Case Study | Checklists  | Concentration Diagrams | Histograms | Pie Charts | Run Charts | Scatter Diagrams |