Dave Pollard has posted a great summary of The Wisom of Crowds. I'd like to focus on this bit:

The group's answer, he shows, is almost invariably better than any expert's answer, even better than the best answer of the experts in the group. The group's answer is the collective answer, a term Surowiecki prefers to 'average' or 'consensus' answer, which aren't always the same thing. And the superiority of the collective answer depends importantly on the group's members having three qualities:

- Intellectual diversity: Different opinions and perspectives (unlike most management teams and boards, who tend to select others who think the same way they do),
- Independence: Freedom from the tendency to want to agree automatically with what one or more other group members says, and
- Decentralization with Aggregation: Individual access to different, specialized knowledge, and a mechanism for effectively sharing that knowledge with the rest of the group.

...Surowiecki drops his first bombshell early: "There is no evidence that one can become expert in something as broad as decision-making, policy, or strategy...or perhaps even management. ... Large groups of diverse individuals will make more intelligent decisions than even the most skilled decision-maker." The implication of this is that business executives, expert consultants, investment analysts, egomaniacal doctors and heads of state are not competent to make important decisions related to cognitive, coordination or cooperation problems, and should always defer to the collective wisdom of large diverse groups when such problems arise.

,,,The book describes at length the phenomenon of groupthink and how it biases groups' decisions and gives collective wisdom a bad name. In fact there are four phenomena at work: The tendency of groups to excessively rationalize away minority views as improbable, the shyness of individuals to voice the first opposing view in the face of an apparent consensus, the tendency to accept consensus of a small number as inherent 'proof' of that consensus' validity, and the bandwagon tendency of groups to be infected by what Gladwell in The Tipping Point called an 'epidemic'.

I like this! I'm interested in the distinction between a collective decision and a consensus and I've long been fascinated by groupthink and have many times experienced groups where the consensus is a low common denominator, with many responses suppressed in favour of cosy agreement.

This seems to provide more evidence of the value of people really "showing up" to relationships, being willing to express contrary views and bring more of their responses, emotional and intellectual, to bear in group decision-making.