What is “Fish Bone Diagram” and how to implement it?

The beginning:

This method was developed by “Kaoru Ishikawa” who pioneered the quality management process in KAWASAKI shipyards and became one of the founding fathers of modern management. The basic concept was first used in 1920 and became popular in the 1960s.

Dr. Edwards Deming also adopted this technique. Both Ishikawa and Deming used this diagram as one of the first tools in the quality management approach. Dr. Deming has taught methods of quality management in Japan since WW2 to the Japanese army.

The rational of the technique:

This technique’s philosophy is based on the (Effect) is the problem you are dealing with, however, there is a hidden cause you need to find in order to eliminate and solve the problem permanently.

This tool helps to identify the contributing factors to the problem. Therefore, further investigation can be conducted. It is commonly used for product design and quality defect prevention.

This method is also called the “Ishikawa diagram” or “fishbone diagram” because its shape looks like a side view of a fish skeleton.

How does it work?

The Fishbone diagram works with complex problems and gives a comprehensive vision of the whole process. In addition, it is considered a good tool to visualize the situation to stakeholders.

Fishbone diagram process:

1. Assemble a team:

The problem-solving team should contain people who have hands-on experience and knowledge of the process. People who are close to the problem see more details than anybody else and are probably able to propose practical solutions.

2. Identify the problem:

Identifying the problem is the most crucial step in any problem-solving technique. As it is the starting point of the whole process and the foundation that all efforts will be based on.

3. Identify the possible casual factors:

There are typical categories of each business or industry. These categories include all functions the business needs to run. They are the factors or causes of the problem. Each potential cause is traced back to find the root cause, often using the (five Whys, appreciation, and drill down) techniques.

Typical categories include:

Originating with lean manufacturing and the Toyota Production System, the 5 Ms is one of the most common frameworks for root-cause analysis: [1]

The 5 Ms (used in manufacturing)

• Man / mind power (physical or knowledge work, includes suggestions)
• Machine (equipment, technology)
• Material (includes raw material, consumables, and information)
• Method (process)
• Measurement / medium (inspection, environment)

These have been expanded by some to include an additional three, and are referred to as the 8 Ms: [2]

• Mission / mother nature (purpose, environment)
• Management / money power (leadership)
• Maintenance

The 8 Ps (used in product marketing)

This common model for identifying crucial attributes for planning in product marketing is often also used in the root-cause analysis as categories for the Ishikawa diagram: [3]

• Product (or service)
• Price
• Place
• Promotion
• People (personnel)
• Process
• Physical evidence
• Performance

The 8 Ps are primarily used in product marketing.

The 4 Ss’ (used in service industries)

An alternative used for service industries uses four categories of possible causes : [4]

• Surroundings
• Suppliers
• Systems
• Skill

4. Write down the problem (the effect) on the side of a paper or board.

5. Identify the relevant category according to the type of business (you may refer to the typical categories in step two or manage your categories according to your process). Then draw the branches off the main one. Each category is a potential cause where you can find the defect in.

6. Brainstorm every cause to identify the sub causes, and then draw branches off every category to write down the sub causes you identified.

7. Break down each sub cause into its elements. Then Draw your lines off the sub causes you determined in the previous step.

8. Analyze your diagram by asking the following questions:

How likely is this cause to be the major source of the issue or variation?

• V – Very Likely
• S – Somewhat Likely
• N – Not Likely

How easy would it be to fix or control?

• V – Very Easy
• S – Somewhat Easy
• N – Not Easy

Put the answers to the two questions together. Work on the Causes that have a result of VV, VS, and SV. [5]

Example:

Using this method will illustrate the complexity of a “late delivery” problem.

The problem-solving team identified the problem by observing the frequent complaints about late delivery. Then collected data about the whole delivery process and all tasks that needed to be done to make the delivery on the expected time and decided to analyze it by a “fishbone” diagram according to the complexity of the problem.

Step two: Determining the possible casual factors by including all categories, which can be the causes of the problem.

Step three: Brainstorm each cause and find the sub causes:

Step four: Break down each sub-cause into its elements. Then Draw your lines off the sub causes you determined in the previous step.

Step five: Analyze your diagram by asking the following questions:

• How likely is this cause to be the major source of the issue or variation?
• How easy would it be to fix or control?

Step Six: Determine the root cause(s) of the problem.

Step seven: you may use one of the other problem-solving techniques (5whys, appreciation, and drill down) to analyze each element for more details if needed.

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[1] Weeden, Marcia M. (1952). Failure mode and effects analysis (FMEAs) for small business owners and non-engineers: determining and preventing what can go wrong. ISBN 0873899180. OCLC 921141300.

[2] Bradley, Edgar (2016-11-03). Reliability engineering: a life cycle approach. ISBN 978-1498765374. OCLC 963184495.

[3] Bradley, Edgar (2016-11-03). Reliability engineering: a life cycle approach. ISBN 978-1498765374. OCLC 963184495.

[4] Dudbridge, Michael (2011). Handbook of Lean Manufacturing in the Food Industry. John Wiley & Sons. ISBN 978-1444393118. OCLC 904826764.

[5] “Fishbone Diagram – How to Make and Use a Fishbone Diagram”. www.lbspartners.ie. LBSPartners. Retrieved 17 August 2017.