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Quality Improvement Course

Affinity Diagram

Definition: A group decision-making technique designed to sort a large number of ideas, process variables, concepts, and opinions into naturally related groups. These groups are connected by a simple concept.

Purpose: To sort a list of ideas into groups.

Guidelines:

  • Insure ideas are described with phrases or sentences.
  • Minimize the discussion while sorting -- discuss while developing the header cards.
  • Aim for 5-10 groups.
  • If one group is much larger than others, consider splitting it.

How to Conduct an Affinity Sort:

  • Conduct a brainstorming session on the topic under investigation.
  • Clarify the list of ideas. Record them on small cards or Post-It notes.
  • Randomly lay out cards on a table, flipchart, wall, etc.
  • Without speaking, sort the cards into "similar" groups based on your gut reaction. If you don't like the placement of a particular card, move it. Continue until consensus is reached. Create header cards consisting of a concise 3-5 word description; the unifying concept for the group. Place header card at top of each group.
  • Discuss the groupings and try to understand how the groups relate to each other.

Tips:

  • Inquire whether ideas are adequately clarified.
  • Use only 3-5 words in the phrase on the header card to describe the group.
  • If possible, have groupings reviewed by non-team personnel.
  • While sorting, physically get up and gather around the area where the cards are placed.
  • Team members will ultimately reach agreement on placement, if for no other reason than exhaustion.
  • Sorting should not start until all team members are ready.
  • If an idea fits in more than one category or group, and consensus about placement cannot be reached, make a second card and place it in both groups.

Affinity Sort  - This example documents the delays Internal Medicine residents encounter when discharging patients.  It is the basis for this fishbone diagram.

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