Relation Diagram in New 7 QC Tools

A Relation Diagram, also called an Interrelationship Diagram, is one of the New 7 QC Tools used in quality management and problem-solving. It helps teams identify the logical relationship between different causes and effects in a complex problem.

This tool is widely used in:

• Total Quality Management (TQM)
• Lean Manufacturing
• Root Cause Analysis
• Quality Improvement Projects
• Six Sigma
• Problem Solving Activities

A relation diagram encourages multi-directional thinking and helps identify the most influential factors affecting a process or problem.

What is a Relation Diagram?

A relation diagram is a visual management tool used to show the relationship between ideas, causes, and effects using arrows.

It is especially useful when:

• Many factors are interrelated
• The root cause is unclear
• A problem is complex
• Multiple departments are involved

The arrows in the diagram show which factor influences another factor.

Relation Diagram Meaning in TQM

In Total Quality Management (TQM), a relation diagram helps teams:

• Identify root causes
• Understand interconnections
• Prioritize corrective actions
• Improve decision-making

It converts confusing information into a structured visual format that is easier to analyze.

Purpose of a Relation Diagram

The main objectives of using a relation diagram are:

• Identify major causes of a problem
• Understand cause-and-effect relationships
• Find key drivers affecting performance
• Improve team understanding
• Support effective decision-making

When to use a Relation Diagram?

A relation diagram is used in the following situations:

1. Complex Problem Solving

When the problem has many interconnected causes and effects.

2. Root Cause Analysis

To identify the major driving causes behind a problem.

3. Planning Activities

During project planning or process improvement activities.

4. After Brainstorming

After preparing:

• Affinity Diagram
• Fishbone Diagram
• Tree Diagram

5. Cross-Functional Issues

When different departments influence the problem.

Benefits of Relation Diagram

Better Understanding of Problems

It helps teams visualize relationships clearly.

Identifies Key Causes

The diagram highlights the most influential factors.

Improves Team Participation

Encourages collaborative brainstorming and analysis.

Supports Decision Making

Helps prioritize improvement actions.

Enhances Logical Thinking

Develops analytical and systematic thinking.

How to Create a Relation Diagram?

Follow these simple steps to prepare a relation diagram:

Step 1: Define the Problem

Clearly write the problem statement at the center or top of the chart.

Example:

Frequent rejection in Welding process.

Step 2: Brainstorm Possible Causes

Collect all possible causes related to the problem.

Examples:

• Operator skill
• Machine condition
• Welding parameters
• Material quality
• Maintenance issues

Step 3: Arrange Related Ideas

Place related ideas close to each other.

Step 4: Draw Relationship Arrows

Draw arrows from the influencing factor toward the affected factor.

The arrow direction shows:

• Cause → Effect
• Influence → Result

Step 5: Analyze the Diagram

Count:

• Incoming arrows
• Outgoing arrows

Factors with:

• More outgoing arrows → Major causes
• More incoming arrows → Final effects

Example of Relation Diagram

A company plans to install a new welding robot in the assembly line.

Different issues are identified:

• Operator training
• Space availability
• Power supply
• Programming skills
• Budget approval
• Maintenance planning

The team prepares a relation diagram to identify which factors have the maximum influence on successful robot installation.

Relation Diagram Symbols

Difference Between Relation Diagram and Fishbone Diagram

Applications of Relation Diagram

Relation diagrams are widely used in:

• Manufacturing industries
• Automotive companies
• Quality management systems
• Lean manufacturing projects
• TPM activities
• Process improvement
• Six Sigma projects

Relation Diagram in New 7 QC Tools

The Relation Diagram is one of the New 7 QC Tools, also known as the 7 Management and Planning Tools.

The New 7 QC Tools are:

1. Affinity Diagram
2. Relation Diagram
3. Tree Diagram
4. Matrix Diagram
5. Prioritization Matrix (Matrix Data Analysis)
6. PDPC (Process Decision Program Chart)
7. Arrow Diagram

Tips for Effective Relation Diagram

• Keep statements short and clear
• Avoid duplicate ideas
• Involve cross-functional team members
• Use brainstorming techniques
• Focus on logical relationships
• Highlight major influencing factors

Common Mistakes While Preparing Relation Diagram

• Drawing too many unnecessary arrows
• Using unclear problem statements
• Ignoring team participation
• Confusing causes with effects
• Not analyzing outgoing and incoming arrows properly

Conclusion

A Relation Diagram is a powerful quality management tool used to analyze complex relationships between causes and effects. It helps organizations identify root causes, improve teamwork, and take better decisions during problem-solving activities.

In Lean Manufacturing, TQM, and Six Sigma projects, the relation diagram plays an important role in identifying the most influential factors affecting quality and productivity.

For organizations aiming for continuous improvement, learning and applying relation diagrams can significantly improve analytical thinking and process understanding.

For deep drive about New 7 QC Tools: ASQ- Seven Management and Planning Tools

FAQs on Relation Diagram

What is a relation diagram?

A relation diagram is a quality management tool used to identify logical relationships among different factors in a complex problem.

Is relation diagram part of New 7 QC Tools?

Yes, relation diagram is one of the New 7 QC Tools used in planning and management activities.

What is another name for relation diagram?

It is also called an Interrelationship Diagram.

What is the main benefit of a relation diagram?

It helps identify the key driving causes in a complex problem.

Where is relation diagram used?

It is used in:

• TQM
• Lean Manufacturing
• Six Sigma
• Root Cause Analysis
• Process Improvement Projects