Quantitative Sozialforschung




Ability or Diversity: How to Boost the "Wisdom" of Groups

In the last decade interest in the "wisdom of crowds" effect has gained momentum both in organizational research and in corporate practice. "Crowd wisdom"' relies on the aggregation of a set of independent judgments. The accuracy of a group's aggregate prediction rises with the number, ability, and diversity of its members. In this project, we investigate these variables' relative importance for collective approximation using agent-based simulation.

We test the ''diversity trumps ability'' proposition for large groups, showing that samples of heterogeneous agents outperform same-sized homogeneous teams of high ability. In groups smaller than a dozen members, however, the effects of group composition depend on the social decision function employed: Diversity is of key importance only in continuous estimation tasks (averaging) while much less so in discrete choice tasks (voting), in which agents' individual abilities remain crucial. Thus, strategies to improve collective decision-making must adapt to the predictive situation at hand.

Furthermore, we investigate how social influence affects the wisdom-of-crowd effect. Conventional knowledge has it that social influence (i.e., being informed about others’ judgments) undermines this effect. The great potential of groups to come up with accurate decisions, it says, relies on the combination of members’ independent judgments. Social influence, instead, narrows the variation of individual judgments, preventing individual guesses to “bracket the truth” and eventually tipping their central tendency away from the true value. This project demonstrates that social influence’s negative consequence is far from universal. Undesirable outcomes only occur if group decisions rest on the averaging principle. Under voting, the most widespread social decision rule, social influence contributes to information aggregation and can thus be advantageous for collective accuracy.


Ganser, C., Keuschnigg, M, 2018 (forthcoming): Social Influence Strengthens Crowd Wisdom Under Voting. Advances in Complex Systems.

Keuschnigg, M., C. Ganser, 2016: Crowd Wisdom Relies on Agents' Ability in Small Groups with a Voting Aggregation Rule. Management Science.


  • Social Influence Strengthens Crowd Wisdom Under Voting. Interdisciplinary Workshop on Opinion Dynamics and Collective Decision, Jacobs University Bremen, July 2017.
  • How to Boost the "Wisdom" of Groups: An Experiment and a Simulation. Forschungskolloqium Empirie, Universität Bern, Oktober 2013.
  • Size, Ability, or Diversity: How to Boost the "Wisdom" of Groups. Kongress der Schweizerischen Gesellschaft für Soziologie, Bern, Juni 2013.
  • Diversität und die "Weisheit" von Gruppen. Sektionsnachmittag "Theoretische und methodische Konzepte von Diversität" der Sektion Modellbildung und Simulation der DGS beim 36. DGS-Kongress, Ruhr-Universität Bochum, Oktober 2012.


Marc Keuschnigg (E-Mail), Christian Ganser (E-Mail)