Joshua Becker and Edward “Ned” Smith in Havard Business Review: “How useful is the wisdom of crowds? For years, it has been recognized as producing incredibly accurate predictions by aggregating the opinions of many people, allowing even amateur forecasters to beat the experts. The belief is that when large numbers of people make forecasts independently, their errors are uncorrelated and ultimately cancel each other out, which leads to more accurate final answers.
However, researchers and pundits have argued that the wisdom of crowds is extremely fragile, especially in two specific circumstances: when people are influenced by the opinions of others (because they lose their independence) and when opinions are distorted by cognitive biases (for example, strong political views held by a group).
In new research, we and our colleagues zeroed in on these assumptions and found that the wisdom of crowds is more robust than previously thought — it can even withstand the groupthink of similar-minded people. But there’s one important caveat: In order for the wisdom of crowds to retain its accuracy for making predictions, every member of the group must be given an equal voice, without any one person dominating. As we discovered, the pattern of social influence within groups — that is, who talks to whom and when — is the key determinant of the crowd’s accuracy in making predictions….(More)”.