Interrelationship Diagraph

An Interrelationship Diagraph, sometimes referred to as an Interrelationship Digraph, is a visual tool used to identify and display the relationships and interactions between various factors, issues, or ideas within a complex system. This diagramming technique is commonly employed in quality management, problem-solving, and decision-making processes, particularly in the context of Total Quality Management (TQM) and Six Sigma methodologies.

Purpose and role:

The primary purposes of an Interrelationship Diagraph are:

  1. Identify relationships: The diagram helps uncover the complex interactions and dependencies between different elements within a system, allowing users to understand how they are interconnected.
  2. Analyze cause and effect: By identifying the causal relationships between factors, an Interrelationship Diagraph can reveal the root causes of problems or issues, guiding the prioritization of improvement efforts.
  3. Facilitate decision-making: By providing a visual representation of relationships, the diagram aids in decision-making by clarifying the potential impacts of proposed changes or solutions.
  4. Encourage collaboration: The process of creating an Interrelationship Diagraph often involves collaboration among team members, fostering open communication and shared understanding of the system's complexities.


An Interrelationship Diagraph typically consists of:

  1. Nodes: Circles or boxes that represent the factors, issues, or ideas being analyzed. Each node corresponds to one element within the system.
  2. Arrows: Directed lines connecting the nodes, which represent the relationships or interactions between the elements. The direction of the arrow indicates the cause-and-effect relationship (i.e., the direction of influence).
  3. Looping arrows: Arrows that connect nodes in a circular manner, representing feedback loops or cyclical relationships.

Importance and benefits:

Interrelationship Diagraphs are important because they:

  1. Enhance understanding: By visually displaying relationships and interactions, the diagrams improve understanding of complex systems and their underlying dynamics.
  2. Support problem-solving: The diagrams help identify root causes and prioritize improvement efforts, which can lead to more effective problem-solving and decision-making.
  3. Facilitate communication: The visual nature of the diagrams makes it easier to communicate complex relationships and system dynamics, promoting shared understanding among team members.

Examples to illustrate key concepts:

Consider a manufacturing company experiencing production delays. An Interrelationship Diagraph might be used to analyze the factors contributing to the delays, such as equipment failures, employee training, and supply chain issues. By creating a diagram that maps the relationships between these factors, the team can better understand the underlying causes and identify opportunities for improvement.

In summary, an Interrelationship Diagraph is a visual tool used to identify and display relationships and interactions within a complex system. It helps enhance understanding, support problem-solving, and facilitate decision-making by revealing the underlying dynamics of the system. The diagram is particularly useful in quality management and process improvement methodologies, such as TQM and Six Sigma.

See Also