The Fishbone Diagram

This is a video explaining what the fishbone diagram is, why it is useful and how to implement it step by step.

Below is the complete script of the video.


Fishbone Diagram

There are many creativity techniques available to help generate ideas for problem-solving.

In this video, I will show you fishbone diagram techniques that have a more structured approach.

Shortly, the fishbone diagram can be defined as a Visual Tool used to identify, explore and visualize all the possible causes related to a problem. It helps to find the root cause of the problem.

This method can be used in a group and it is helpful if you need to tackle problems on your own.

The fishbone diagram is also known as the Ishikawa diagram from the name of Kaoru Ishikawa who popularized it.

It is also known as the Cause and Effect Diagram and it is normally used in the Analyze phase of the Six Sigma process.

You can do this on your own or preferably in a larger group.

If you use a group, you should have a diverse group including different functions.

If your group spans different levels of hierarchy or if there are conflicts among the team members, you may choose to have them write cards or give ideas in turn to mitigate the internal conflict.



Fishbone Diagram and 4M

You start with the problem or effect, which would be the head of the fish.

Starting from the head of the fish, you draw different bones, one for each category of causes that could generate the effect.

There are quite a few options for these bones.

Most common is man, machine, material, method, also known as 4M.



Fishbone Diagram Example

Let’s take an example.

A company has a recurring defect on a hole diameter.

It is decided to tackle the problem through the fishbone diagram.

The facilitator organizes a cross-functional workgroup that works in a room with the help of a large whiteboard to draw the fishbone diagram.

The problem is placed in the head of the fishbone. Diameter out of tolerance.

The 4Ms are written on the 4 bones of the fishbone.


The facilitator asks each member of the group to write down the possible causes of the problem on post-its.

The post-its are subsequently collected by the facilitator and with the help of the group are placed in the appropriate category.

In case there are duplicate causes, they are considered as possibly more relevant as contributing to the problem.

After this brainstorming phase, the facilitator leads the discussion to decide with the group the causes that are considered most influential on the generation of the problem.

The simple voting method can be used for this phase.

Typically 2 or 3 main causes are selected and countermeasures are proposed for these causes.

In this example, we could imagine that the team decided to focus on these 3 root causes.

1) Drill bit material not suitable.
2) Unclear work instructions.
3) Unsuitable machinery.

For each of these causes, the group should go into detail with a 5 why’s analysis.

For these reasons, action plans are developed that must be implemented and monitored.




The fishbone diagram is a simple and inexpensive tool to find the root causes of a problem, align the team, and involve everyone in the resolution.

It is very important to have an experienced facilitator who can guide the group through the problem-solving process.

The more the team will practice applying the fishbone diagram for problem-solving, the faster and more effective it will become.