Theory and Decision

, Volume 73, Issue 3, pp 465–499 | Cite as

Conflicting evidence and decisions by agency professionals: an experimental test in the context of merger regulation

  • Bruce Lyons
  • Gordon Douglas Menzies
  • Daniel John Zizzo


Many important regulatory decisions are taken by professionals employing limited and conflicting evidence. We conduct an experiment in a merger regulation setting, identifying the role of different standards of proof, volumes of evidence, cost of error and professional or lay decision making. The experiment was conducted on current practitioners from 11 different jurisdictions, in addition to student subjects. Legal standards of proof significantly affect decisions. There are specific differences because of professional judgment, including in how error costs and volume of evidence are taken into account. We narrow the range of explanations for why professional decision making matters.


Belief conservatism Experiment Merger control Professionalism Standard of proof 

JEL Classification

L33 L40 L50 C91 


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Copyright information

© Springer Science+Business Media, LLC. 2011

Authors and Affiliations

  • Bruce Lyons
    • 1
  • Gordon Douglas Menzies
    • 2
  • Daniel John Zizzo
    • 3
  1. 1.School of Economics and the ESRC Centre for Competition PolicyUniversity of East AngliaNorwichUK
  2. 2.School of Finance and EconomicsUniversity of Technology SydneyBroadwayAustralia
  3. 3.School of Economics, Centre for Competition Policy and Centre for Behavioural and Experimental Social ScienceUniversity of East AngliaNorwichUK

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