Fishbone Diagram Maker

How the Fishbone Diagram Maker works

Fishbone diagram maker: from a list of causes to a picture

A fishbone diagram puts a problem in the head of a fish and its possible causes along the bones. The point is to brainstorm widely before jumping to a fix, and to group causes so the team can see which area has the most suspects. Typing the list is faster than drawing it, keeps the session moving and means a cause can be moved between categories by cutting and pasting a line.

Where the diagram comes from

Kaoru Ishikawa, a Japanese quality-control engineer, popularised the diagram in the 1960s, and it is also known as an Ishikawa or cause-and-effect diagram. It is one of the classic seven basic tools of quality and turns up in Lean, Six Sigma and incident reviews. Manufacturing teams often start with the "6 Ms": Manpower (people), Methods, Machines, Materials, Measurement and Mother Nature (environment). Service teams often use People, Process, Policies, Place and Systems instead. The categories are a prompt, not a rule.

Writing the list

• The first line is the problem, written as an effect: "Late customer deliveries".
• Any line that is not indented starts a new category.
• Lines indented with spaces or a tab are causes in the category above. A leading "-" is optional.
• Lines starting with "#" are comments.

Categories alternate above and below the spine, left to right, in the order you type them.

Using it in a root cause session

Write causes as facts that could be checked, such as "Label printer jams twice a week", not "bad printer". Ask "why?" of each cause until the answers stop being useful, and add the deeper answers as more causes. When the diagram is full, pick the two or three causes with the most evidence and test them. The diagram shows possibilities, not proof. To map what happens next, a flowchart of the fixed process or a decision tree of the options works well.

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