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Process improvement project - Define -

What is it for?


This tool identifies connections and relationships between topics or people. 

It can also be used to look at ideas within a topic and help to focus on the main idea that emerges.




Some clues about what to ask during the drawing of an Interrelationship Diagram are


  • Must this happen before that can happen?

  • You must to this in order to achieve that

  • Does one topic help or influence the other topic?

  • Does one topic tend to follow the other topic?



How to draw an Interrelationship Diagram?


STEP 1 -

Take your topics (you may have these already if you created an Affinity Diagram or Fishbone Diagram) and place them in a circle on a flipchart or wall.

STEP 2 - 

Look at each pair to see if there is a relationship.  Take one relationship at a time.  In this example:

·         Document Errors + Product Quality

·         Document Errors + Packaging

·         Document Errors + Delivery

·         Document Errors + Labelling

·         Document Errors + Pricing

·         Document Errors + Product number

·         Document Errors + Other


You may choose the question "Does this Document Error help or influence product quality?"  The answer is likely to be no, so there is no relationship here. 


If you ask the same for Document Error + Delivery, the answer may be yes, as if a document is generated with an incorrect shipping address, the Delivery will be affected.

STEP 3 -

As you find a relationship, draw a line between the two topics


STEP 4 - 

Then start with Product Quality and complete the relationship for each of the other cards

STEP 5 - 


Now count the number of arrows OUT and the number of arrows IN for each topic.  In this example, Product Quality shows 2 arrows OUT and 1 arrow IN.

STEP 6 - 

Write the totals on each card

STEP 7 - 

Find the Topic that contains the most number of OUT arrows, as this is the topic which is impacting most other processes. 


In this example, Labelling has 5 out arrows and therefore is the largest cause of issues.

Some Tips and Tricks to consider:
  • Do not use two headed arrows, you won't be able to count them later.  Use only one line and arrow for OUT and one for IN

  • Only one line type allowed to indicate if there is a relationship or not.  Do not use dotted lines

  • If you cannot decide if there is a relationship on one of the cards, leave it and go back to it at the end.




A good understanding of the issues; Identifies the largest contributor.

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