Affinity process

Skill level: Basic


An affinity diagram is a tool that organizes large amounts of data into related categories based on their natural relationships. Typically used in conjunction with a brainstorming exercise as a subsequent step, affinity diagrams tend to have 40 to 60 items; however, it is not unusual to see 100 to 200 items.


  • Collects and organizes large data sets
  • Helps to develop relationships or themes among ideas
  • Helps to reduce attributes to categories that can be addressed at a higher level

How to Use

  • Step 1. Conduct a brainstorming session on the topic to capture ideas on cards or sticky notes, or use the output from a previously conducted brainstorming session.
    • *Tip: Written ideas should be between three and seven words long.
  • Step 2. Attempt to look for relationships between individual ideas and have team members simultaneously sort the ideas (without talking) into five to 10 related groupings.
    • *Tip: It is important to call these “groupings.”
  • Step 3. From these relationships, attempt to define categories and create summary or header cards for each grouping or category.
    • *Tip: Header Cards should clearly identify the common thread for all groupings and should be descriptive of that thread.
  • Step 4. Assign all ideas to the identified categories by placing ideas under header cards.
    • *Tip: Base assignment on “gut feel,” not through contemplation.

Relevant Definitions

Brainstorming: An activity used to generate ideas on a particular topic. Each participant is asked to capture as many ideas relating to the topic as possible, and then all ideas are collected from the group and recorded.


Company SQBOK seeks to understand the difficulties around and excessive time needed for onboarding new employees. A team of hiring managers, new employees, human resource managers, and peer employees conducted a brainstorming session and identified 15 problems. In an affinity process, all of the ideas were written down on “sticky” pages affixed to a board.

A separate group charged with managing the onboarding process was asked to identify any commonalities or relationships between the ideas. The group identified four main categories: training, paperwork, regulatory, and technology. Each idea was categorized under these general areas. Company SQBOK can now track these four areas and assign them to the appropriate groups for resolution. The process also highlights areas of deficiency.

Details of this exercise, which highlights improvement opportunities for the team, are shown in the table below.


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