Also called: interrelationship diagram or digraph, network diagram
Variation: matrix relations diagram
The relations diagram shows cause–and–effect relationships. Just as importantly, the process of creating a relations diagram helps a group analyze the natural links between different aspects of a complex situation.
When to Use a Relations Diagram
- When trying to understand links between ideas or cause–and–effect relationships, such as when trying to identify an area of greatest impact for improvement.
- When a complex issue is being analyzed for causes.
- When a complex solution is being implemented.
- After generating an affinity diagram, cause–and–effect diagram or tree diagram, to more completely explore the relations of ideas.
Relations Diagram Basic Procedure
Materials needed: Sticky notes or cards, large paper surface (newsprint or two flipchart pages taped together), marking pens, tape.
- Write a statement defining the issue that the relations diagram will explore. Write it on a card or sticky note and place it at the top of the work surface.
- Brainstorm ideas about the issue and write them on cards or notes. If another tool has preceded this one, take the ideas from the affinity diagram, 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.
- Place one idea at a time on the work surface and ask: “Is this idea related to any others?” Place ideas that are related near the first. Leave space between cards to allow for drawing arrows later. Repeat until all cards are on the work surface.
- 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.
- Analyze the diagram:
- 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.
- Note which ideas have primarily outgoing (from) arrows. These are basic causes.
- Note which ideas have primarily incoming (to) arrows. These are final effects that also may be critical to address.
Be sure to check whether ideas with fewer arrows also are key ideas. The number of arrows is only an indicator, not an absolute rule. Draw bold lines around the key ideas.
Relations Diagram Example
A computer support group is planning a major project: replacing the mainframe computer. The group drew a relations diagram (see figure below) to sort out a confusing set of elements involved in this project.
Relations Diagram Example
“Computer replacement project” is the card identifying the issue. The ideas that were brainstormed were a mixture of action steps, problems, desired results and less-desirable effects to be handled. All these ideas went onto the diagram together. As the questions were asked about relationships and causes, the mixture of ideas began to sort itself out.
After all the arrows were drawn, key issues became clear. They are outlined with bold lines.
- “New software” has one arrow in and six arrows out. “Install new mainframe” has one arrow in and four out. Both ideas are basic causes.
- “Service interruptions” and “increased processing cost” both have three arrows in, and the group identified them as key effects to avoid.
Excerpted from Nancy R. Tague’s The Quality Toolbox, Second Edition, ASQ Quality Press, 2004, pages 444-446.