Groupthink and bad decisionmaking

From "U turn if you want to on the road to a bad decision," in the Financial Times:

This botched invasion of Cuba is often held up as the definitive example of "groupthink", that process by which, the psychologist Irving Janis said, "the (group) members' strivings for unanimity override their motivation to realistically appraise alternative courses of action".

Close-knit teams are particularly susceptible to the pull of groupthink. The late Prof Janis suggested several ways in which teams can avoid it. Two key steps are to invite experts from outside into meetings, and to appoint at least one person to the role of "devil's advocate" - a role that should be played by different people in successive meetings.

Why do clever people make bad decisions? No doubt groupthink explains why some boards end up committing to an idiotic course of action. Cowardice may stop people who know better from speaking up. But what if everybody is acting in good faith, is drawing on good data and apparently relevant experience? What explains the bad decisions that do undeniably get made even in these propitious circumstances?

See Essence of Decision by Allison, Groupthink and Decision Making by Janis and Mann and even The Andromeda Strain by Crichton...