An Affinity Diagram is very similar to brainstorming. It is a group decision-making process designed to sort a large number of ideas, variables, concepts, and/or opinions into naturally related groups. Ideas are written on post-it notes and then organized into logical categories and labeled.  The end result is similar to a tree map.
 

1. Is the problem (or issue) complex and hard to understand?
2. Is the problem uncertain, disorganized, or overwhelming?
3. Does the problem require the involvement and support of a group?

1. Choose a group leader.
2. State the issue or problem.
3. Brainstorm and record ideas.
4. Move the cards into like categories.
5. Name each category with a header card.
6. Draw the affinity diagram.
7. Discuss the categories.