What is a fishbone diagram ?

As a Business Analyst, you would regularly have to analyze the root cause of various identified problems. One of the common tools that is used to perform the root cause analysis is called a fishbone diagram.

A fishbone diagram, a cause and effect diagram or an Ishikawa diagram as it is also commonly known, is used to represent the potential causes of a problem in order to identify it’s root causes.

The diagram looks very much like the a skeleton of a fish, hence the name the fishbone diagram.

Before the fishbone diagram is drawn, some initial analysis has to be performed. Some of the common techniques that are used to perform this analysis include the five why’s, mind maps and brainstorming.

After the initial analysis is conducted, the business analysis would have enough information to start drawing the fishbone diagram.

So how do you create a fishbone diagram ?

Fishbone diagrams are usually drawn on a flipchart or whiteboard to identify the cause of a problem.

The Business Analyst might organize a brainstorming session to identify the potential cause of the problem. The attendees of this brainstorming session would be stakeholders of the process, who can help with identifying the cause of the problem.

So let us create a fishbone diagram with the help of an example:

  1. The problem: In this example the organization’s Enterprise Resource Planning (ERP) software is producing an error message when the end users try to print a form or a report. This problem statement would be written on the head of the “fish” and a box would be drawn around it.
  2. Draw the backbone of the fish: Then a horizontal arrow is drawn with an arrow pointing to the head, this would be the backbone of the fish.
  3. Brainstorm: Then Brainstorming attendees would identify possible causes of the error message. These could include : has the ERP license expired, has the ERP application support contract ended, is the SQL database producing any error message, is the server CPU running out of memory ? etc.
  4. Group the potential causes: You can group these potential causes into groups such as methods, skills, equipment, people, materials and environment. These causes are then drawn to branch off from the spine with arrows, making them the first bones of the fish.
  5. Split the potential causes into the groups: The potential causes are drawn as smaller branches or subdivisions of these bigger groups. For each potential cause, the stakeholders should brainstorm any additional information that may support it, this usually involves some sort of analysis technique such as the 5 Whys. This process continues until the root causes to the problem is identified.

So when should you use a fishbone diagram ?

A fishbone diagram is useful in the following situations:

  1. To help identify the possible causes of a problem.
  2. To help with product development in order to fulfil the customer’s needs.
  3. To identify bottlenecks and vulnerabilities in a business process.
  4. To ensure that the solution would the problem.
A fishbone diagram