A team’s goal is to improve information flow in a payroll function. They make thirty-three Post-It® notes, each listing an issue for further investigation. After some discussion, they group them into four categories: mandated record keeping, privacy concerns, insurance concerns and transfer concerns. This grouping process is best described by which approach to problem solving?

An affinity diagram (also called the K-J method) is used after brainstorming to take dozens of individual ideas written on cards/Post-Its and sort them into naturally occurring groups so that the team can see common themes before moving to deeper analysis. The team in the question generated 33 issues and then clustered them into four topic areas—exactly the textbook definition of an affinity-diagram activity.

B. Inter-relationship digraph maps cause-and-effect links among already-grouped ideas; it does not perform the initial clustering.
C. Tree diagram breaks a single objective into successively finer levels; it is not a method for sorting brainstormed ideas.
D. PDPC adds potential failure modes and countermeasures to a plan; it is used after a tree diagram, not for idea grouping.
E. Matrix diagram cross-plots two (or more) sets of items to show strength of relationships, not to create categories themselves.
F. Prioritization matrix ranks alternatives against weighted criteria; it requires predefined categories and scoring, not open clustering.
G. Activity network diagram (PERT/CPM) sequences tasks with time dependencies; unrelated to categorizing qualitative issues.

1. ASQ. The Certified Six Sigma Black Belt Handbook, 4th ed., 2022, Ch. 6 “Seven Management Tools,” pp. 237–240: definition and use of affinity diagrams.

2. Brassard, M., & Ritter, D. “The Seven Management and Planning Tools.” Quality Engineering, 1994, 6(1), pp. 13–18 (affinity diagram description). DOI:10.1080/08982119408918643.

3. MIT OpenCourseWare, Course 16.660 “Intro to Lean Six Sigma,” Lecture 8 notes, slide 12: affinity diagram purpose—“organize large numbers of ideas into natural groupings.”

4. Goetsch, D., & Davis, S. Quality Management for Organizational Excellence, 9th ed., 2022, Sec. 10-3, pp. 319–320: explanation of affinity diagram vs. other management tools.