(Extracted from Principles by Ray Dalio)
1+1=3. Two people who collaborate well will be about three times as effective as the two of them operating independently because they will see what the other might miss, they can leverage each other, and they can hold each other to higher standards. This symbiotic relationship of adding people to a group will have incremental benefits (2+1=4.25) up to a point at which there are no incremental gains and beyond which adding people produces incremental losses in effectiveness. That is because 1) the marginal benefits diminish as the group gets larger—e.g. two or three people might be able to cover most of the important perspectives so adding more people doesn’t bring much more, and 2) larger group interactions are less efficient than smaller group interactions. Of course, what’s best in practice is a function of 1) the quality of the people and the differences of the perspectives that they bring and 2) how well the group is managed. As noted before, each group should have someone who is responsible for managing the flow to get out of the meeting the most possible.