What is an Interrelationship Diagram

What is an Interrelationship Diagram?

→ An interrelationship diagram represents the relationship between the factors in a complex situation.

→ This tool easily identifies the difficult relations between the various factors.

→  This tool helps us to identify the Cause and Effect Relationship of the critical issues.

→ This analysis helps us to differentiate between the issue and cause or we can say that the driving factors and the outcomes of that activity.

→ We can also use this tool to identify logical relationships in a complex and confusing problem situations.

→ This tool is a part of a New 7 QC Tools (Seven Management and Planning Tools).

→ The Interrelationship_Diagram also visualizes the relationships between the various factors.


Different Names of an Interrelationship Diagram

  1. Interrelationship diagraph,
  2. Relations_Diagram or Digraph,
  3. Network_Diagram


When to use the Interrelationship Diagram?

→ We need to use this_diagram when we are trying to understand the relationship between ideas or cause_and_ffect relationships.

→ We can use it during the analysis of a complex issue or a situation.

→ After creating an Affinity_Diagram, Fishbone_Diagram, or Tree_Diagram, we can use the Interrelationship_Diagram for detailed and further analysis. 

→ Use an Interrelationship_Diagram can also be useful in identifying root_causes, even when objective data is not available.


How to Make an Interrelationship Diagram?

→ Materials needed: Sticky notes or cards, large paper surface, marking pens.

→ We can divide the diagram making process into below simple four steps.

  1. Identify and define the Issue or Problem
  2. List down all ideas/activity
  3. Draw and count the arrow as per cause and effect relationship
  4. Analysis of the Interrelationship Diagram


Step 1: Identify and define the Issue or Problem

→ Define the statement of the problem for that we need to make an Interrelationship_Diagram.

→ Write the problem on a sticky note and place it at the top of a whiteboard or blank paper surface.


Step 2: List down all ideas/activity

→ Brainstorm ideas about the issue and write them on sticky notes. In other words, we can say develop issues related to the problem.

→ After that, we need to identify the relationships.

→ Using any of the issues as a starting point, work through the relationships in sequence.


Step 3: Draw and count the arrow as per cause and effect relationship

➨ For each pair of issues, determine the below three possibilities.

     (a) No cause and effect relationship,

     (b) A weak cause_and_effect relationship,

     (c) A strong cause_effect relationship.

→ If the team determines there is a cause_and_effect relationship then also determine which issue is the cause and which is the result.

→ Draw arrows to indicate directions of influence or we can say that the direction of the arrow should be from an influencer (affecting to) to influence by (get affected).

➨ Draw arrow based on below two types.

     (a) For strong relationships, use a solid line.

     (b) For a weaker relationship, draw a dashed line.

→ Although some relationships may seem evenly balanced, always determine which is the stronger influence and draw the arrow in that direction.

→ At a time we need to use only a single-headed arrow to avoid two-headed arrows.

→ For each issue, clearly record the number of arrows going in and going out.

→ Count the arrow in and an arrow out for each idea and note down the counts of arrow either at the bottom of each box or side of the box.

→ The box has the highest arrows that are the key activity/idea and also keep it in mind that the count of arrows is the only indicator it is not a final one.

→ Sometimes the idea/activity having a lesser number of arrows is also a key activity or idea.

→ At finally, draw a bold box around the key ideas.


Step 4: Analysis of Interrelationship Diagram

→ Now we need to analyze the_diagram to identify drivers and outcomes.

→ We can identify the basic causes for which ideas have primarily outgoing (from) arrows.

→ Then the final effects can be identified as the ideas have primarily incoming (to) arrows. And the final effects may be very critical to address.

→ A high number of outgoing_arrows indicate that an issue is a driver or possible root cause.

→ The idea with a higher number of incoming arrows known as a key issue or key concern.



Example of an Interrelationship Diagram

→ For a Better understanding of the Interrelationship_Diagram, we are taking one example and we will refer to the above-mentioned steps for making the diagram.


Step 1: Identify and define the Issue or Problem

→ So in the very first steps, we need to Define the Problem or identifying the issue. In this example, we will take the below issue.

➨ Issue/Problem: Poor Communication of the Product Dispatch/Shipping.


Step 2: List down the cause and effect relations for all ideas/activity

➨ As per the brainstorming, we have found below ideas or points that are related to Poor Communication of the Product Dispatch/Shipping.

     ⇢ Poor Communication with Logistic Provider

     ⇢ Poor Communication with Dispatch Department

     ⇢ Poor Planning

     ⇢ Poor Scheduling of Logistic Provider

     ⇢ Poor Maintenance of Truck

     ⇢ Late Order From Customer

     ⇢ Breakdown in Truck

     ⇢ Late Delivery of Raw Material

     ⇢ Other Orders in Progress

Case Study of Interrelationship Diagram


Step 3: Draw and count the arrow as per cause and effect relationship

→ Now as per the next step we will find out the cause and effect relationship and drawing the incoming and outgoing_arrows.

→ After that, we need to count the arrows in and out for each idea.

→ Write the counts at the bottom of each box.

→ These all things we can easily show in the below picture.

Example of Interrelationship Diagram


Step 4: Analysis of Interrelationship Diagram

A. Identify the Key Cause (Driver)

→ From which idea or point having the highest number of output_arrows is called a driver or key cause.

→ In other words, a key cause affects a large number of other items.

→ The above diagram shows the following key causes:

→ Poor Planning - (5 outgoing_arrows)

→ Late Order From Customer - (5 outgoing_arrows)

B. Identify the Key Concern

→ A Concern or Idea with a large number of Input_arrows is affected by a large number of other concerns or ideas.

→ Thus, It could be a source of quality or performance metric.

→ Poor Scheduling of Logistic Provider - (4 Incoming_arrows)

→ A Measure of Poor Scheduling of Logistic Provider could create the problem of Late Delivery.


Advantages of an Interrelationship Diagram

→ This tool very easily analyze the cause and effect relation of any problem

→ A very complex issue can be easily solved by this tool

→ Sometimes this tool is used to identify the Root Cause Analysis

→ This tool is very easy to use and analyze


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