Interrelationship Diagram

Introduction: Interrelationship Diagram

An Interrelationship Diagram is a tool used to explore cause-and-effect relationships among complex issues. It helps teams see how different factors influence each other and identify which ones have the greatest impact on a problem or situation.

Background

The Interrelationship Diagram is part of the Seven Management and Planning Tools, developed in Japan to support quality management and problem-solving. It is often used after an Affinity Diagram, where grouped ideas are further analysed to reveal their connections.

Key Elements / Features

• Visual network – Ideas or issues are written in boxes and connected with arrows showing influence.
• Cause and effect – Arrows point from a cause to the issue it influences.
• Drivers and outcomes – Factors with many outgoing arrows are root causes (drivers), while those with many incoming arrows are outcomes (effects).
• Clarity – Makes hidden relationships visible in complex systems.

Applications / Examples

In healthcare, an Interrelationship Diagram might be used to explore delays in patient admissions, linking causes such as “staff shortages,” “poor IT systems,” and “unclear procedures.” In business, it could help identify which market factors drive customer dissatisfaction.

The diagram is usually created in workshops:

1. Write down key issues from brainstorming or Affinity Diagram.
2. Connect related issues with arrows to show influence.
3. Count arrows to identify main drivers and effects.
4. Use this insight to focus improvement efforts.

Relevance / Impact

The Interrelationship Diagram helps teams deal with complexity by identifying leverage points for change. It supports root cause analysis, guides decision-making, and ensures improvements focus on the most influential issues.

See also

• Affinity Diagram
• Root Cause Analysis
• Cause-and-Effect Diagram
• Seven Management and Planning Tools