In this  article I'd like to take you through an improvement tool called the fishbone diagram.

It's often referred to as the Ishikawa diagram, after its inventor.

You may have heard people talk about cause and effect diagrams.

It's the same thing.

The fishbone diagram was developed by Dr. Kaoru Ishikawa in the
1960's in the Kobe Shipyards in Japan.

I remember the name by calling it a Fishikawa diagram. Sad I know!

Kaoru is the same person that came up with the idea of Quality
Circles.

The cause and effect diagram is looked upon as one of the seven
classic quality tools.

A finished Ishikawa diagram looks a bit like the bones of a fish.

Fishes come in such an amazing variety of shapes and sizes that
there is no 'typical' fish skeleton.

Just like fish, an Ishikawa diagram can be big or small depending on
the complexity of the issue being investigated.

When do we use it?

We usually use a fishbone diagram when we are trying to get to
the root cause of a problem, which has many possible causes. It
can be a useful tool to use during a kaizen blitz event to help
define quality problems in a format that is easily understood.

What will it give us?

Creating this diagram gives us a pictogram of a chosen
issue and the potential root causes. It's a great way to document
the 5 Why's which we've talked about before, in a previous issue of
Instant Improvement.

Is it easy to use and how do we create one?

It's a very simple and flexible tool.

It is best constructed with a group of up to 10 people.

All you need is a pen, a ruler and a large surface to write on.

The first thing we do is draw a horizontal line in the centre of the
page and at the end of the line draw a box on the far right and in
it write the effect or problem you want to investigate.

We then draw a few angled lines either side of the main
line, spaced out.

We then brainstorm some main root causes and add them to the end of
each angled line. It should start to look like a fishbone. We can
then get the group to add sub causes to each of the main causes
until the diagram is complete.

Here is an example

Creating your own template for your type of business

Sometimes it can be useful to pre-determine the headings
at the end of each branch.

In a manufacturing situation you can use the 6m's as branch headings
to get you started.

Machines, Methods, Materials, Measurement, Man and Mother Nature
(the environment)

In an office environment you can use the 8P's.

Price, Promotion, People, Processes, Place, Policies, Procedures, Product

Or the 4S's

Surroundings, Suppliers, Systems and Skills

Of course you don't need to use any of these if you don't want to.
You can mix and match as you see fit or make up your own.


In conclusion

The fishbone diagram is a quick and easy improvement tool that
can help you identify root causes to sometimes quite difficult
problems. It's a great way of collating group input in a
pictorial form, that everyone can understand.

Hope this helps

Till next time. Happy fishing.

Hope this helps.

Best regards,

Graham Ross

Back to Lean Kaizen Welcome Page from Fishbone Diagram article

Get Free Lean Kaizen Toolkit

Back to Lean Kaizen Artcles