What is an affinity relationship?
Often, you may know that two roles or two task cases have something in common or are similar in some way but not know precisely what relationship they have. A vague or unspecified similarity is called an affinity. In the interest of quickly getting insight into the overall structure of a problem, we often start out by doing an affinity clustering. Putting the task cases (or user roles) on index cards or Post-it notes simplifies sorting them into groups or loose collections of similar or related examples. Specifics can be worked out later, but at least this way we know how things go together.