Got a problem that keeps coming back? You’re probably just treating the symptoms instead of the root cause. Enter the fishbone diagram—a simple but powerful tool that helps teams get to the heart of recurring issues.
Here’s a breakdown of what it is, why you should use it, and how to make one yourself.
1. What’s a Fishbone Diagram?
A fishbone diagram (also called an Ishikawa or cause-and-effect diagram) is used to figure out why a problem is happening. Picture a fish: the head is the problem you’re solving, and the “bones” are potential causes. You organize these causes into categories, like People, Processes, or Technology.
This tool was invented in the ‘60s by Japanese quality control expert Kaoru Ishikawa. It’s still a go-to for businesses using Lean, Six Sigma, and other problem-solving methods.
2. Why Use It?
Fishbone diagrams help you move past the obvious symptoms and find out what’s really going on.
- Structure your thinking: You don’t miss key causes because everything’s laid out in one place.
- Collaborate better: Teams from different departments can share insights.
- Prevent quick fixes: By focusing on root causes, you avoid bandaid solutions that won’t last.
3. How to Create a Fishbone Diagram
Step 1: Define the problem
Be clear and specific. Instead of “quality issues,” go with something like “20% product defect rate over the last three months.”
Step 2: Draw the fish
• Draw a straight line for the “spine.”
• Write the problem at the “head” (right side).
Step 3: Add categories (the main ‘bones’)
These are common ones, but you can adjust them to fit your situation:
• People: Skills, training, communication issues
• Processes: Steps not followed or unclear procedures
• Materials: Poor quality or supply issues
• Technology: Outdated systems or faulty equipment
• Environment: External factors like market trends or regulations
Step 4: Brainstorm causes
Ask questions like “Why is this happening?” over and over until you dig deep. This is where the 5 Why’s method can help.
Step 5: Find the root cause
Once you’ve brainstormed all possible causes, look for recurring patterns or the causes with the biggest impact. This is your root cause.
4. Do’s and Don’ts
Do’s:
✅ Involve a mix of people with different expertise.
✅ Be specific and data-driven.
✅ Ask “Why?” multiple times to go deeper.
Don’ts:
❌ Don’t just treat symptoms.
❌ Avoid vague problem definitions.
❌ Don’t make the diagram so complicated that nobody can follow it.
5. How It Fits into Lean Problem Solving
In Lean problem-solving, a fishbone diagram helps teams drill down into causes and prioritize fixes. It pairs well with other methods like A3 problem-solving and the 5 Why’s. Think of it as a starting point to organize your thoughts before deciding on countermeasures.
6. 5M vs. 8P: Which Version Should You Use?
When creating a fishbone diagram, you’ll often hear about two common frameworks for the categories: 5M and 8P. Both work well, but they’re suited to slightly different situations. Here’s a quick breakdown to help you choose the right one:
5M (Common in Manufacturing & Engineering)
This version focuses on technical and operational factors that often cause problems in production environments.
The 5Ms are:
1. Man (People): Skills, training, or staffing issues
2. Machine: Equipment, tools, or technology problems
3. Method: Processes, procedures, or instructions
4. Material: Quality or availability of raw materials or components
5. Measurement: Data collection errors or inaccurate KPIs
When to use:
The 5M approach is ideal for manufacturing, logistics, or other operations-driven industries where processes and technology are key.
8P (Common in Services & Marketing)
The 8P categories are more customer-focused and useful in industries like marketing, sales, and service delivery. They reflect a broader view of organizational factors.
The 8Ps are:
1. Product: The product or service itself
2. Price: Pricing strategy or value perception
3. Promotion: Marketing and communication efforts
4. Place: Distribution channels or locations
5. People: Employees, training, or customer interactions
6. Processes: Workflow, procedures, or automation
7. Physical Evidence: Tangible aspects (e.g., packaging, branding)
8. Performance: Results, KPIs, or customer outcomes
When to use:
The 8P framework works best in service-oriented businesses or when analyzing customer experience issues.
7. Ready to Start? Download my Free Template!
Want to give this a try? I’ve got you covered with a free fishbone diagram template.
For more insights on Lean tools, check out our posts on the 5 Why’s and A3 Problem Solving. Need more help? Reach out to us [here].