Abstract: Many decisions rest upon people’s ability to make estimates of some unknown quantities. In these judgments, the aggregate estimate of the group is often more accurate than most individual estimates. Remarkably, similar principles apply when aggregating multiple estimates made by the same person – a phenomenon known as the “wisdom of the inner crowd”. The potential contained in such an intervention is enormous and a key challenge is to identify strategies that improve the accuracy of people’s aggregate estimates. Here, we propose the following strategy: combine people’s first estimate with their second estimate made from the perspective of a person they often disagree with. In five pre-registered experiments (total N = 6425, with more than 53,000 estimates), we find that such a strategy produces highly accurate inner crowds (as compared to when people simply make a second guess, or when a second estimate is made from the perspective of someone they often agree with). In explaining its accuracy, we find that taking a disagreeing perspective prompts people to consider and adopt second estimates they normally would not consider as viable option, resulting in first- and second estimates that are highly diverse (and by extension more accurate when aggregated). However, this strategy backfires in situations where second estimates are likely to be made in the wrong direction. Our results suggest that disagreement, often highlighted for its negative impact, can be a powerful tool in producing accurate judgments.
From a paper by Van de Calseyde and Efendić.
What this means is that diversity can improve group thinking but you need cognitive diversity, i.e. you need people in the group who disagree with one another not people who all agree despite superficial differences.
Another simple tool to make judgment more accurate is the premortem.
Hat tip: The excellent Steve Stewart-Williams.