Affinity diagram
An affinity diagram is a way of organizing a large set of research observations or ideas by grouping related items into clusters and naming each cluster. Also called affinity mapping or the KJ method, it builds categories from the data upward.
How it works
Each observation, quote or idea goes on its own sticky note or digital card. The team spreads the notes out and, usually in silence at first, moves related notes together. Groups form, split and merge until each cluster holds one idea, and the team then writes a label that says what the cluster is about. Labels can be grouped again into higher-level themes.
Because there are no predefined categories, the structure comes from the data itself, which is the method's strength in exploratory research. The KJ method is named after the Japanese anthropologist Jiro Kawakita, and quality managers use the same technique to sort causes and ideas.
A worked example
A consumer electronics brand's insights team finishes 24 interviews about home setup and has 310 observations. In a two-hour session, the team sorts them into 19 clusters, then 5 themes. The largest theme, "I don't know which cable goes where", holds 71 notes from 20 of the 24 participants.
Related
Automate this in Pulse
Each quote under a Pulse theme can go on its own sticky note, so an affinity session starts from participants' exact words instead of a note-taker's paraphrases.