Fish Bone

Fish Bone Diagram Also Called: Cause-and-Effect Diagram, Ishikawa Diagram

Description:

Identifies many possible causes for an effect or problem. It can be used to structure a brainstorming session. It immediately sorts ideas into useful categories.

When to Use

• When you try to know possible causes for a problem.

• Especially when a team’s thinking tends to fall into block way.

Procedure:

1- Agree on the problem (effect). Write it at the center right ( Fish Head ) of the flipchart or whiteboard . Draw a box around it and draw a horizontal arrow running to it.

.....................................> Problem

2- Brainstorm the major categories of causes of the problem (5M ).

• Methods

• Machines (equipment)

• Manpower (People)

• Materials

• Measurement

• Environment

3- Write the categories of causes as branches from the main arrow.

4- Brainstorm all the possible causes of the problem. Ask: “Why does this happen?” As each idea is given, write it as a branch from the appropriate category(5M ).

Causes can be written in several places if they relate to several categories.

5- Again ask “why does this happen?” about each ( CAUSE from step 4 ). Write sub-causes branching off the causes. Continue to ask “Why?” and generate deeper levels of causes. Layers of branches indicate causal relationships.

N.B.: When the group runs out of ideas, focus attention to places on the chart where ideas are few.