The Wisdom of Crowds


The Wisdom of Crowds

Author: James Surowiecki



This is a comprehensive review of group decision-making and the factors that influence this. The book discusses how the composition of the group and the structure of the organisation influence the decisions they make. The main point the book makes is that group diversity is essential for effective decision-making. The author, a journalist, argues that groups made of independent members, with different backgrounds, make wiser decisions (page10). This enables different views to be aggregated (page 29) and allows the group to view problems in new ways and to apply a wider choice of possible solutions (page 36). Diverse group have a higher chance of coming up with innovative ideas because each member brings a different insight to the problem, and this insight outweighs what individual intelligence or expertise bring to group decision-making (page 30-31). The author therefore urges that important decisions should never be left to a few members no matter their expertise (page 32).




The author uses several anecdotes to illustrate the principles of group decision-making which he advocates. A typical example he narrated is how diversity and collaborative research led to the quick identification of the SARS-causing corona virus. The diverse research teams involved in this brought different kinds of knowledge and perspectives and were able to distribute cognitive labour (page 161-162). Citing examples of the Bay of pigs invasion and mutual fund management, he demonstrated the grave consequences of decision taken by homogenous groups; he says in such groups, ‘….information that might represent a challenge to the conventional wisdom is either excluded or rationalized as obviously mistaken…’ and ‘…people come away from discussions with their beliefs reinforced, convinced more than ever that they’re right’ (page 37). He argues that homogenous groups ‘share an illusion of invulnerability, a willingness to rationalize away possible counterarguments to the groups position, and a conviction that dissent is not useful’ (page 37). Such groups are often under pressure to conform and are likely to adopt extreme views thereby fostering groupthink (page 38).




The importance of diversity seems more important when the group membership is small, a situation that allows a few biased or influential members to skew the decision-making process (page 29-30).  The author maintains that members of small groups are more susceptible to the influence of co-members (page 176) and he illustrated this with the example of the Columbia shuttle disaster. He therefore advocates that diversity should be actively selected in small groups. Large groups however are also liable to err in decision-making by the phenomena of social proof and herding: individual members do what other members are doing because it is a less risky option (pages 43 and 49). In this context, the book distinguishes between intelligent and slavish imitation (page 60). He supports his assertions with studies from sociologists and psychologists such as Hazel Knight, Kate Gordon, Irving Janis, Solomon Asch, Stanley Milgram, Scott Page and James Shenteau.

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The author addressed the issue of organisational structure in detail. He was critical of the typical hierarchical, centralized and multi-layered structure of most institutions which are geared towards achieving consensus (page 203). On the contrary he advocates for a decentralised decision making process where ‘…decisions about local problems should be made, as much as possible, by people close to the problem’ (page 211). This has the added advantages of improving local engagement and reducing excessive and costly supervision (page 212-213). He uses the Toyota production system to illustrate this (page 213).” target=”_blank”>

The author speaking on the wisdom of crowds


How should groups undertake the process of decision-making? The author suggests that group members should give their opinions as autonomously and simultaneously as possible to avoid the effect of information cascade whereby ‘…people are making decisions based on what they think people who came before them knew…’ (page 54). To foster debate, the author says discussions should be structured, and the group leader should ensure that everyone has a chance to speak. He points out that dissenting views may be stifled if dominant members speak first, and he warns against the inappropriate influence of more talkative members, powerful advocates of specific agendas, and excessive deference to status. An illusion of consensus may arise when final decision is taken; the book suggests that this may be reduced by producing a minority opinion (pages 183-188).


This is a very enjoyable book to read, filled to the brim with insightful details on group decision-making. The author convincingly argues the case for group diversity and provides unassailable evidence for this. With examples from fields such as healthcare and the automotive industry, he illustrates the consequences of group structure on the quality of decisions. His opinion that diversity trumps expertise is perhaps controversial and I think the author should have emphasised that this is more relevant in some fields of endeavour than others. It was disappointing that the book did not have an index; apart from this there is very little else to criticise about the book which has an excellent writing style, appropriate illustrative examples, and a great cover.


This is a very important review of group-decision making and it makes very cogent arguments. Whilst many of the examples he gives are not healthcare-related, the themes the author explores are central to healthcare decision-making. For this reason I recommend the book to all doctors.


  • Publisher, place, date: Abacus, London, 2004
  • Edition: 1st
  • Number of chapters: 12
  • Pages: 295
  • ISBN: 0-349-11605-9
  • Price: £7.49
  • Star rating: 5 stars


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