# Round-robin pair-wise meetings

December 14, 2011 1 Comment

A procedure for a group that wants to ensure every person gets to meet or talk with each other person (e.g., when an academic department wants each person to learn about each others’ work during the past year):

- arrange N/2 pairs of chairs facing each other in an inner and outer circle. Leave a gap so the circles are more of a C shape.
- if there is an odd number of people, place an extra chair at the right (or counterclockwise) end of the outer circle.
- if there is an even number of people, place an extra chair at the right (or counterclockwise) end of the outer circle and at the right (clockwise) end of the inner circle (see diagram below).
- ask people to find a seat. If there is an even number of people, leave the two end chairs empty at the start.

- in the pairs the people meet or talk with each other for the time allotted (e.g., 3 minutes for speed dating). If someone at the end is unpaired they have a break.
- people in the outer circle move to their left (clockwise; see arrows above). The person at the end moves to the vacant chair at the end of the inner circle.
- in the pairs the people meet or talk with each other for the time allotted (e.g., 3 minutes for speed dating). If someone at the end is unpaired they have a break.
- people in the inner circle move to their left (counterclockwise; see arrows above). the person the end moves to the vacant chair at the end of the outer circle.

- repeat these four steps (i.e., the ones below the diagram) until everyone has been paired with everyone else. (If there are N people this will take N rounds of meeting/talking followed by one of the circles moving.

In theory, the minimum time for an even-sized group would be N-1 rounds, but with people only having to move every second round, you might prefer this procedure. If you do not mind people moving every round, try this:

- arrange N/2 pairs of chairs facing each other (or [N+1]/2 pairs for an odd-sized group). If these are in an inner and outer circle, leave a gap so the circles are more of a C shape.
- ask people to find a seat.
- In an odd-sized group, one person will have no pair at first. That person stays put when everyone else moves after each round of the two steps ahead. If there is an even-sized group, one person (say at one end) is chosen to say put.

- in the pairs the people meet or talk with each other for the time allotted (e.g., 3 minutes for speed dating). In an odd-sized group, the person unpaired has a break.
- people, except for the one person who stays put, move clockwise one chair, moving from the inner to the outer circle or vice versa as needed. (The unfilled chair moves around as well.)

Published in 2012: http://link.springer.com/chapter/10.1007%2F978-3-642-30347-0_6#page-1