Cause and Effect Diagram (Fishbone Diagram)

🎯 Cause and Effect Diagram (Fishbone Diagram)

📌 Definition:

A Cause and Effect Diagram, also known as a Fishbone Diagram or Ishikawa Diagram, is a visualization tool used to systematically identify, explore, and display all the possible causes of a specific problem (effect). It helps teams to identify root causes rather than just symptoms.

🐟 Why It’s Called Fishbone Diagram:

The diagram resembles the skeleton of a fish:

The head of the fish represents the problem or effect.
The bones branching off the spine represent major cause categories.
Sub-branches under each major category represent possible contributing factors.

🔍 Purpose:

To identify the root causes of a problem.
To organize and categorize potential causes.
To promote brainstorming and systematic analysis in quality management.

📚 Structure:

The diagram is typically built from:

Effect (problem): written at the head of the fish.
Major cause categories: main branches from the spine.
Root causes and sub-causes: smaller branches off the main ones.

✅ Main Categories: 5M + 1E

This classification is especially used in manufacturing and industrial analysis, but it can be adapted to other industries.

1. Man (People):

Refers to human-related causes.
Examples:
- Inadequate training
- Operator error
- Lack of experience
- Miscommunication

2. Machine:

Refers to equipment, technology, and tools.
Examples:
- Equipment malfunction
- Poor maintenance
- Outdated machinery
- Inconsistent calibration

3. Method:

Refers to processes, procedures, and policies.
Examples:
- Lack of standardized work
- Inefficient procedures
- Non-compliance with SOPs
- Poor planning

4. Material:

Refers to raw materials, components, or consumables.
Examples:
- Low-quality materials
- Incorrect materials
- Defective parts
- Variability in materials

5. Measurement:

Refers to inspection, testing, and data collection methods.
Examples:
- Inaccurate data
- Faulty measurement systems
- Lack of measurement standards
- Misinterpretation of results

6. Environment:

Refers to external conditions (physical, social, or organizational).
Examples:
- Temperature or humidity variations
- Poor lighting or noise
- Cultural or organizational environment
- Safety hazards

🛠 Steps to Create a Fishbone Diagram:

Define the Problem: Write the effect (problem) at the head of the fish.
Draw the Main Backbone: This is the central line pointing to the problem.
Identify Major Categories: Use 5M+1E or categories relevant to your context.
Brainstorm Causes: For each category, list potential causes and sub-causes.
Analyze: Look for root causes, relationships, and areas to investigate further.
Take Action: Use findings to develop corrective or preventive actions.

🧠 Tips for Use:

Use cross-functional teams for broader insights.
Don’t rush; focus on identifying root causes, not just surface symptoms.
Combine with other tools (e.g., 5 Whys, Pareto Analysis) for deeper root cause analysis.