The Interrelationship diagram shows cause-and-effect relationships. Just as importantly, the process of creating an interrelationship
diagram helps a team analyze the natural links between the different
aspects of a complex situation.
When to Use:
*When trying to understand the links between ideas or
cause-and-effect relationships, such as identifying the area
of greatest impact for improvement.
*When analysing a complex issue for causes.
*When implementing a complex solution.
Interrelationship Diagram Construction:
Gather sticky notes or cards, large paper surface (newsprint or two flipchart pages taped together), marking pens and tape.
1. Write a statement defining the issue for the relations
diagram. Write it on a card or sticky note and place it at
the top of the work surface.
2. Brainstorm ideas about the issue and write them on individual cards or notes.
If another tool such as an affinity diagram preceded this one, take the ideas from the affinity
diagram or the most detailed row of the tree diagram or the final
branches on the fishbone diagram. You may want to use these ideas as
starting points and brainstorm additional ideas.
3. Place one idea at a time on the work surface. For each idea, ask: "Is this idea
related to any others?" Place ideas that are related together.
Leave space between the cards to allow for drawing arrows. Repeat
until all cards are on the work surface.
4. For each idea, ask, "Does this idea cause or influence any other
idea?" Draw arrows from each idea to the ones it causes or influences.
Repeat the question for every idea.
5. Analyze the diagram:
6. Count the arrows in and out for each idea. Write the counts at the bottom of each box. The ones with the most arrows are the key ideas.
7. Note which ideas have primarily outgoing (from) arrows. These are the basic causes.
8. Note which ideas have primarily incoming (to) arrows. These are final effects that also may be critical to address.