Definition
An organizing method in which scattered verbal information is written on cards, grouped creatively, and then each group is summarized with a header card. The strict version of the VOC interview module has hard thresholds: compress to about 24 items, land in 8–12 first-level groups, and avoid grouping by cause-and-effect relationships.
In detail
An affinity diagram is an organizational method that writes scattered verbal information on cards, groups them creatively, and summarizes each group with a header card. It is used to organize qualitative data, such as Voice of Customer (VOC) interview results, helping teams identify themes from chaos. Unlike fishbone diagrams, affinity diagrams do not presuppose cause-and-effect relationships but group based on similarity. In the VOC module, the strict version requires compressing to about 24 items, falling into 8-12 first-level groups, and avoiding grouping by cause-and-effect. It typically outputs a grouped affinity diagram as a basis for subsequent analysis.
Example in practice
The product team collected 50 customer feedback items and grouped them using an affinity diagram: first, each person independently wrote cards, then collectively discussed and categorized, finally forming 8 groups such as "usability," "performance," and "price." Each group was summarized with a header card. The team found that "usability" was mentioned most frequently, so they listed it as an improvement priority.