Don't abandon national referendums, but smaller groups often make wiser choices

[Plazma Inferno!]

New research by scientists from the Max Planck Institute for Human Development in Berlin suggests that larger crowds do not always produce wiser decisions. In fact, when it comes to qualitative decisions such as “which candidate will win the election” or “which diagnosis fits the patient’s symptoms,” moderately-sized "crowds," around five to seven randomly selected members are likely to outperform larger ones. In the real world, these moderately-sized crowds manifest as physician teams making medical diagnoses; top bank officials forecasting unemployment, economic growth, or inflation; and panels of election forecasters predicting political wins.
Where previous research on collective intelligence deals mainly with decisions of how much or how many, the current study applies to this-or-that decisions under a majority vote. The researchers mathematically modeled group accuracy under different group sizes and combinations of task difficulties. They found that in situations similar to a real world expert panel, where group members encounter a combination of mostly easy tasks peppered with more difficult ones, small groups proved more accurate than larger ones. This effect is independent of other influences on group accuracy, such as following an opinion leader or having group discussions before voting.

http://www.santafe.edu/news/item/Galesic-wisdom-smaller-crowds/

 

[iceaura]

The absolutely imperative aspect of the smaller group, the key feature upon which all such conclusions rest, is the one I've bolded for emphasis in this quote from the link:

In fact, when it comes to qualitative decisions such as “which candidate will win the election” or “which diagnosis fits the patient’s symptoms,” moderately-sized "crowds," around five to seven randomly selected members are likely to outperform larger ones. In the real world, these moderately-sized crowds manifest as physician teams making medical diagnoses; top bank officials forecasting unemployment, economic growth, or inflation; and panels of election forecasters predicting political wins.

The analysts who first demonstrated the benefits of crowd or group decision making were clear on that matter - the independence of the members of the deciding group was critical. They each had to be making their own best decision based on a body of objective evidence and physical fact, otherwise uncorrelated with the other deciders, for the sum to be reliably better than the parts. That's why crowds work - they are mostly strangers to each other, at least with respect to the decision.

That is where the real world normally parts company with the theoretical best practice. That is why panels of "experts" in fields deficient in solid criteria for expertise or circumstances excluding entire bodies of such expertise as exists

- such as the small panels of experts that recommended deregulating the US banking system in the '90s, siting and protecting the Fukushima power plants as they were, or invading Iraq in 2003 -

so invariably go so badly and blatantly (to outsiders) wrong: they aren't independent of each other with respect to their inclusion in the decision group, partly because their status as expert deciders is not based on a physical reality by which independence of judgment can be assessed.