Affinity Diagram is a technique that allows large number of ideas classified into groups for review and analysis.
Within the PMBOK® Guide, Affinity Diagram technique is used in the following processes:
Project Scope Management
Project Quality Management
Affinity diagrams allow large number of ideas to be classified into groups for review and analysis. As an example, the figure shows a set of techniques grouped under heads like creativity techniques and decision making techniques. In turn they belong to a master group tools and techniques – “Collect Requirements”
In the below figure, the Affinity diagram is given cost of quality under the heads of Conformance Vs Non-Conformance. This further helps to identify the area that should be focused first for improvement, so that the investment on quality is justifiable
PMBOK® GUIDE SIXTH EDITION