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''The Wisdom of Crowds: Why the Many Are Smarter Than the Few and How Collective Wisdom Shapes Business, Economies, Societies and Nations'', published in 2004, is a book written by James Surowiecki about the aggregation of information in groups, resulting in decisions that, he argues, are often better than could have been made by any single member of the group. The book presents numerous case studies and anecdotes to illustrate its argument, and touches on several fields, primarily economics and psychology. The opening anecdote relates Francis Galton's surprise that the crowd at a county fair accurately guessed the weight of an ox when their individual guesses were averaged (the average was closer to the ox's true butchered weight than the estimates of most crowd members, and also closer than any of the separate estimates made by cattle experts).〔 Introduction (page XII): Although Surowiecki's description of the "averaging" calculation (page XIII) implies that Galton first calculated the ''mean'', inspection of the original 1907 paper indicates that Galton considered the ''median'' the best reflection of the crowd's estimate. ( ). Galton's quotation from the end of this paper (given by Surowiecki on page XIII) actually refers to the surprising proximity of the median and the measurement, and not to the (much closer) agreement of mean and measurement (which is the context Surowiecki gives it in). The mean (only 1 pound, rather than 9, from the ox's weight) was only calculated in Galton's subsequent reply to a letter from a reader, though he still advocates use of the median over any of the "several kinds" of mean (); he thinks the median, which is analogous to the 50% +1 vote, particularly democratic.〕 The book relates to diverse collections of independently deciding individuals, rather than crowd psychology as traditionally understood. Its central thesis, that a diverse collection of independently deciding individuals is likely to make certain types of decisions and predictions better than individuals or even experts, draws many parallels with statistical sampling; however, there is little overt discussion of statistics in the book. Its title is an allusion to Charles Mackay's ''Extraordinary Popular Delusions and the Madness of Crowds,'' published in 1841. ==Types of crowd wisdom== Surowiecki breaks down the advantages he sees in disorganized decisions into three main types, which he classifies as * Cognition : Thinking and information processing : Market judgment, which he argues can be ''much'' faster, more reliable, and less subject to political forces than the deliberations of experts or expert committees. * Coordination : Coordination of behavior includes optimizing the utilization of a popular bar and not colliding in moving traffic flows. The book is replete with examples from experimental economics, but this section relies more on naturally occurring experiments such as pedestrians optimizing the pavement flow or the extent of crowding in popular restaurants. He examines how ''common understanding'' within a culture allows remarkably accurate judgments about specific reactions of other members of the culture. * Cooperation : How groups of people can form networks of trust without a central system controlling their behavior or directly enforcing their compliance. This section is especially pro free market. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「The Wisdom of Crowds」の詳細全文を読む スポンサード リンク
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