Re-creative managers( The fishbone diagram)

Fishbone Diagram (Proposed by Professor Ishikawa of Tokyo University)

How does the Fishbone Diagram work?

This is a simple tool that allows quick and effective understanding of the root causes of a problem, through the pursuit of corrective actions to solving that problem. Often referred to a cause and effective diagram, Fishbone diagram is a simple root cause analysis tool that is used for brainstorming issues and causes of a particular problem(s).  The diagram resembles a fishbone structure and allows ideas to be sorted into useful categories. Categories are classed according to the degree of importance starting with the most important to least important.

How to apply the Fishbone Diagram (Use flipchart or Whiteboard and marking pens)

1.       Agree on a problem statement 

2.       Brainstorm the major categories of causes of the problem.

3.       Write the categories of causes as branches from main arrow according to simpler relationships

4.       Brainstorm all the possible causes of the problem. Ask: “Why does it happen?” Write each answer in the appropriate category.

5.       Continue to ask “Why?” Write sub-causes branching off the causes, generate deeper levels of causes. Layers of branches will indicate causal relationships

6.       When group runs out of ideas, focus attention on the chart where ideas are few.  

Fishbone Diagram (All aspects)

Diagram shows a typical fishbone template

The diagram picks out the main causes of a problem and indicates the specification/contributing factors for each cause. It also helps to establish a logical sequence for handling various parts of a problem in a systematic way and enables one to visualize the parts within the hole.

The Fishbone Diagram is also known as:

Ishikawa diagram, cause and effect diagram,

Fishbone Diagram Example

This fishbone diagram was drawn by a manufacturing team to try to understand the source of periodic iron contamination. The team used the six generic headings to prompt ideas. Layers of branches show thorough thinking about the causes of the problem.

Fishbone Diagram Example

For example, under the heading “Machines,” the idea “materials of construction” shows four kinds of equipment and then several specific machine numbers.

Note that some ideas appear in two different places. “Calibration” shows up under “Methods” as a factor in the analytical procedure, and also under “Measurement” as a cause of lab error. “Iron tools” can be considered a “Methods” problem when taking samples or a “Manpower” problem with maintenance personnel.