You may have heard of the concept of "wisdom of crowds" in which individuals in a crowd are privately asked to give an answer to a question, such as how many jelly beans are in a jar. Then when the answers are averaged together, the response provided by the crowd is generally better than for any given individual.
This method can be improved by dividing the crowd into smaller groups and asking the small groups to discuss the question and come to a consensus. The result when averaged produces a more accurate figure than the average produced by the large crowd.
You can learn more about the method here
