Number Effects and Tacit Collusion in Experimental Oligopolies
通过元分析和两个新实验（共368名参与者），发现企业数量从2家增加到4家时，默契合谋程度严格递减，并首次证明三家企业比四家企业更易合谋。
We systematically investigate the relationship between the number of firms in a market and tacit collusion by means of a meta‐analysis of the literature on oligopoly experiments as well as two of our own experiments with a total of 368 participants. We show that the degree of tacit collusion decreases strictly with the number of competitors in industries with two, three and four firms. Although previous literature could not affirm that triopolies are more collusive than quadropolies, we provide evidence for this fact for symmetric and asymmetric firms under Bertrand and Cournot competition.