What is an Affinity Diagram?

An affinity diagram is used to organize the collective ideas arising out of a brainstorming session. It is used to create, systematize, and unify information related to a problem, product, complex issue, or process. After generating ideas, a facilitator sorts them according to their similarity or affinity. Kawakita Jiro created it in the 1960s. The chart is also referred to as the KJ method.

How does an Affinity Diagram Work?

The affinity diagram is an idea creation technique which goes by different names, such as thematic analysis, affinity chart, and K-J Method. Times to use the affinity diagram include:

• When the consensus of a group is required.
• When there are many ideas or facts in disarray.
• When problems are too complex and extensive to comprehend.

The ideal situations when the affinity diagram may get used include:

• When organizing and collecting vast sets of data.
• Following a brainstorming activity.
• When analyzing data obtained verbally.
• When establishing themes or relationships between ideas.

With the affinity diagram process, a group navigates away from their preconceived categories and systematic thinking. There is knowledge and comprehension that remains untouched in people's intuition. This technique is a way to access it. 

A regular affinity diagram could have 40 to 60 items but there are times when it could include up to 200. The only materials needed are cards or sticky notes, pens, and a large surface to work on, like a table, wall, or floor. The steps to the process are as follows:

1. Write down each idea on a separate card or sticky note. All the notes should get spread on the work surface, so they are visible to everyone involved in the group.
2. All members of the team gather the notes and find related ideas to put those cards side by side.
3. Have a discussion and define the grouped relationships into categories. The group should come up with a shape for the diagram. Idea notes can be moved around, and the group can make changes when necessary. There should be headers or summaries for all the categories.
4. Together the team members look at the relationships of the ideas and based on the header, decide which idea best represent that particular group as a whole. That note should get placed at the top above all the other related concepts.