Fishbone Diagram Analysis – What It Is and How to Do It

As long as you’re in business, problems will occur. Instead of trying to avoid them, accept them and take rapid action to mitigate their impact.

To solve a problem, you need to have a clear understanding of it. That’s where the Fishbone diagram analysis comes into place.

It’s a way to carry out root cause analysis and break down the core of a problem so you can come up with a solid solution.

In this guide, you’ll learn what a fishbone diagram analysis is, the core components, and how to create one to solve complex problems.

What Is a Fishbone Diagram?

A Fishbone Diagram (referred to as an Ishikawa diagram after the name of its creator) or Cause-and-Effect Diagram is an analysis tool. The main aim is to determine the root cause of a problem.

It was created by Kaoru Ishikawa in the 60s within the framework of Total Quality Management. Like the name implies, it’s a visual representation of a problem that looks like a fish bone or fish skeleton.

The spine of the diagram and the bones are all of the potential causes of the problem.

Purpose

It makes it easier to identify and analyze all the potential reasons for a problem in a systematic manner. You avoid addressing the symptoms alone and get to the root cause. The causes can be organized into multiple categories like equipment, people, processes, environment, management, etc. With these clear categorizations, a complex interwoven problem can be broken down into its component parts.

Key Benefits

There are many benefits associated with fishbone diagram analysis. A few of them are listed below.

• It promotes team collaboration by encouraging brainstorming and different perspectives.
• The visual format helps simplify complex issues, making it easier to communicate findings.
• It prevents jumping to conclusions by ensuring that all possible causes are considered before taking corrective action.

The benefits, when taken together, creates a more effective problem-solving environment. That in turn results in long-term improvements in processes and systems.

Components of a Fishbone Diagram

As mentioned before, there are multiple parts of a fishbone diagram. To perform the analysis properly, you’ll want to incorporate all the components in the right way.

The “Head” (Effect/Problem Statement)

The head is where you lay out the problem you want to analyze or the impact/effect the problem has. The head faces toward the right of the page, which is where the attention of the entire diagram is focused.

It’s important to get this part right. Clearly define the issue so you’ll understand when you’ve arrived at the ideal solution. A clear problem will also focus your efforts. In other words, you won’t have to deal with symptoms or the wrong causes because you know the problem.

The “Spine” (Main Arrow)

The spine connects to the head (problem statement). It’s the structure upon which all the other bones (causes) rest. It serves as the pathway through which the causes are traced back to the source while keeping everything organized for analysis.

The “Bones” (Primary Categories of Causes)

The main bones that connect directly to the spine are categories of causes – not necessarily the causes themselves. The categories will vary depending on the problem and even the industry you’re in. For example:

• Manufacturing Industry Categories: Methods, Machines, Materials, Manpower, Measurement, and Environment (commonly known as the 6Ms). These categories help in analyzing issues related to production quality, process inefficiencies, or equipment failures.
• Service/Business Industry Categories: Policies, Procedures, People, Place, Technology, and Environment. These categories are useful for identifying service-related inefficiencies, customer complaints, or workflow bottlenecks.

You may need to come up with categories specific to your problem or industry. The fishbone diagram analysis method was created in a way that accommodates many different categories.

The “Sub-Bones” (Root Causes and Contributing Factors)

The “sub-bones” extend from the main bones or categories of root causes. It showcases specific causes and contributing factors related to the problem.

Here, you want to go deeper and avoid simple surface-level explanations. The 5 Whys method of root cause analysis may be useful here.

For example, under ‘technology’ in service industries, you may have a cause such as system downtime. You’ll need to go further and ask why there was system downtime. It could be that there is more usage and the system needs upgraded capacity. In essence, by digging deeper you find causes that may not be obvious.

How to Create a Fishbone Diagram

1. Define the Problem Statement

The first step in creating a Fishbone Diagram is to clearly define the problem you want to analyze. A well-articulated problem statement keeps your analysis focused and actionable.

Use specific and measurable terms to describe the issue. Avoid vague language. For example, instead of stating “Delivery issues,” a precise problem statement would be: “Customer complaints about late product deliveries increased by 20% in the last quarter.“ This specificity helps in identifying meaningful root causes.

2. Identify Major Cause Categories

After you’ve defined the problem, determine the major categories of causes that could contribute to it. As mentioned earlier, the problem and your industry will dictate the categories you choose.

Manufacturing problems often use the 6Ms (Methods, Machines, Materials, Manpower, Measurement, and Environment), service industries use different categories, and technology companies may have overlap between all of them. The main thing is that the categories cover the potential areas where the root cause can appear.

3. Brainstorm Potential Causes

With the categories in place, brainstorm possible causes under each category. Consider enlisting the help of others because a diverse team provides multiple perspectives and deeper analysis.

At this stage, focus on generating as many causes as possible without immediately evaluating their validity. This open approach encourages creativity and uncovers hidden issues.

4. Analyze and Prioritize Causes

After brainstorming, analyze the potential causes to identify the most significant contributors to the problem. Use techniques like the 5 Whys to trace deeper root causes by repeatedly asking why a certain issue occurs.

This helps distinguish between surface-level symptoms and fundamental problems. Remove less relevant or redundant causes to streamline the analysis. Doing this allows your efforts to be directed toward the most impactful factors.

5. Develop an Action Plan

Once the root causes are identified, the next step is to develop and implement solutions. Assign responsibility for corrective actions. Make sure each solution has a clear owner and timeline.

Monitor progress and make adjustments as needed to verify that the problem is effectively addressed. Continuous review of the Fishbone Diagram helps refine problem-solving efforts and improve long-term outcomes.

Best Practices for Effective Fishbone Analysis

Use a Structured Approach to Brainstorming

A systematic brainstorming process ensures that all potential causes are explored. Encourage open discussion without immediate judgment, allowing participants to share ideas freely.

Techniques like round-robin brainstorming or affinity grouping can help organize your thoughts and prevent dominant voices from overshadowing other contributions.

Focus on Facts and Data Rather than Assumptions

Basing your analysis on real data rather than assumptions leads to more reliable conclusions. Use historical records, performance metrics, customer feedback, or defect reports to support findings.

Avoid jumping to conclusions without verifying whether a cause contributes to the problem. Data-driven decision-making ensures that corrective actions address actual issues rather than perceived ones.

Validate Findings Through Real-World Observations or Additional Analysis

After identifying root causes, validate them through real-world observations, process audits, or further analysis.

Conducting pilot tests, surveys, or trend analysis helps confirm whether the identified causes are truly responsible for the problem.

Continuous validation prevents unnecessary changes and ensures that corrective actions lead to meaningful improvements.

Conclusion

Fishbone diagram analysis is a powerful method to understand the root cause of problems and develop useful solutions. It does have strict requirements for data quality and analysis but the effort is worth it – especially for impactful problems.

This guide has walked you through the components of the Fishbone diagram, the method to create yours, and best practices.

Now, it’s your turn.

Let me know how it goes in the comments and don’t forget to share.