The Wisdom of Crowds: Why the Many Are Smarter Than the Few and How Collective Wisdom Shapes Business, Economies, Societies and Nations, by James Surowiecki is based on work that the author did as a columnist for The New Yorker.
Many of Surowiceki's arguments seem counter-intuitive, but he cites a fair amount of evidence that the best decisions, on average, are always made by groups rather than individuals regardless of their expertise. In fact, he says: "... the more power you give a single individual in the face of complexity and uncertainty, the more likely it is that bad decisions will get made."
For the group decision-making process to work the best, several elements must be present.
1. A formal process for encouraging disagreement must be present;
2. The group must consist of stakeholders and non-stakeholders, i.e., people normally not part of the group should be present to make sure diversity of opinion is present. Diversity guarantees that multiple perspectives are brought into the decision-making process and that a broader range of information is included;
3. the group must belief and see that it has the responsibility for making decisions. If the decision is made elsewhere, the result is the opposite, i.e., bad results or at least not the best;
4. individuals be independent and have that independence respected to avoid being swayed by a leader or one powerful individual,
5. and there be a process for aggregating the opinions. It's important that pressure to conform be suppressed.
An intelligent group does not ask of its individual members to conform to the dominant view. Instead it creates a mechanism that resembles a democracy or a market. Individual group members get the opportunity to bring in their own information and opinions and are not forced to change their views. Their independence must be explicitly protected.
The first half, or so, of the book is theory (sounds dry, but it's really quite fascinating) followed by some case studies.