@techreport{AndresBruttelFriedrichsen2020,
  type      = {Working Paper},
  author    = {Andres, Maximilian and Bruttel, Lisa Verena and Friedrichsen, Jana},
  title     = {Choosing between explicit cartel formation and tacit collusion - An experiment},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {19},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-47388},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-473885},
  pages     = {55},
  year      = {2020},
  abstract  = {Numerous studies investigate which sanctioning institutions prevent cartel formation but little is known as to how these sanctions work. We contribute to understanding the inner workings of cartels by studying experimentally the effect of sanctioning institutions on firms' communication. Using machine learning to organize the chat communication into topics, we find that firms are significantly less likely to communicate explicitly about price fixing when sanctioning institutions are present. At the same time, average prices are lower when communication is less explicit. A mediation analysis suggests that sanctions are effective in hindering cartel formation not only because they introduce a risk of being fined but also by reducing the prevalence of explicit price communication.},
  language  = {en}
}
@techreport{AndresBruttel2024,
  type      = {Working Paper},
  author    = {Andres, Maximilian and Bruttel, Lisa},
  title     = {Communicating Cartel Intentions},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {77},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-63846},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-638469},
  pages     = {36},
  year      = {2024},
  abstract  = {While the economic harm of cartels is caused by their price-increasing effect, sanctioning by courts rather targets at the underlying process of firms reaching a price-fixing agreement. This paper provides experimental evidence on the question whether such sanctioning meets the economic target, i.e., whether evidence of a collusive meeting of the firms and of the content of their communication reliably predicts subsequent prices. We find that already the mere mutual agreement to meet predicts a strong increase in prices. Conversely, express distancing from communication completely nullifies its otherwise price-increasing effect. Using machine learning, we show that communication only increases prices if it is very explicit about how the cartel plans to behave.},
  language  = {en}
}
@techreport{BruttelPetrishcheva2024,
  type      = {Working Paper},
  author    = {Bruttel, Lisa Verena and Petrishcheva, Vasilisa},
  title     = {Does communication increase the precision of beliefs?},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {74},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-62936},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-629367},
  pages     = {1 -- 33},
  year      = {2024},
  abstract  = {In this paper, we study one channel through which communication may facilitate cooperative behavior - belief precision. In a prisoner's dilemma experiment, we show that communication not only makes individuals more optimistic that their partner will cooperate but also increases the precision of this belief, thereby reducing strategic uncertainty. To disentangle the shift in mean beliefs from the increase in precision, we elicit beliefs and precision in a two-stage procedure and in three situations: without communication, before communication, and after communication. We find that the precision of beliefs increases during communication.},
  language  = {en}
}
@techreport{AndresBruttelFriedrichsen2022,
  type      = {Working Paper},
  author    = {Andres, Maximilian and Bruttel, Lisa Verena and Friedrichsen, Jana},
  title     = {How communication makes the difference between a cartel and tacit collusion},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-56223},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-562234},
  pages     = {67},
  year      = {2022},
  abstract  = {This paper sheds new light on the role of communication for cartel formation. Using machine learning to evaluate free-form chat communication among firms in a laboratory experiment, we identify typical communication patterns for both explicit cartel formation and indirect attempts to collude tacitly. We document that firms are less likely to communicate explicitly about price fixing and more likely to use indirect messages when sanctioning institutions are present. This effect of sanctions on communication reinforces the direct cartel-deterring effect of sanctions as collusion is more difficult to reach and sustain without an explicit agreement. Indirect messages have no, or even a negative, effect on prices.},
  language  = {en}
}
@techreport{BruttelGuethNithammeretal.2020,
  type      = {Working Paper},
  author    = {Bruttel, Lisa Verena and G{\"u}th, Werner and Nithammer, Juri and Orland, Andreas},
  title     = {Inefficient Cooperation under Stochastic and Strategic Uncertainty},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {20},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-47550},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-475500},
  year      = {2020},
  abstract  = {Stochastic uncertainty can cause difficult coordination problems that may hinder mutually beneficial cooperation. We propose a mechanism of ex-post voluntary transfers designed to circumvent these coordination problems and ask whether it can do so. To test this, we implement a controlled laboratory experiment based on a repeatedly played Ultimatum Game with a stochastic endowment. Contrary to our hypothesis, we find that allowing voluntary transfers does not entail an efficiency increase. We suggest and analyze two main reasons for this finding: First, the stochastic uncertainty forces proposers to accept high strategic uncertainty if they intend to cooperate by claiming a low amount (which many proposers do not). Second, many responders behave only incompletely conditionally cooperative by transferring too little (which hinders cooperation in future periods).},
  language  = {en}
}
@techreport{BruttelEisenkopfNithammer2024,
  type      = {Working Paper},
  author    = {Bruttel, Lisa Verena and Eisenkopf, Gerald and Nithammer, Juri},
  title     = {Pre-election communication in public good games with endogenous leaders},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {73},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-62395},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-623952},
  pages     = {28},
  year      = {2024},
  abstract  = {Leadership plays an important role for the efficient and fair solution of social dilemmas but the effectiveness of a leader can vary substantially. Two main factors of leadership impact are the ability to induce high contributions by all group members and the (expected) fair use of power. Participants in our experiment decide about contributions to a public good. After all contributions are made, the leader can choose how much of the joint earnings to assign to herself; the remainder is distributed equally among the followers. Using machine learning techniques, we study whether the content of initial open statements by the group members predicts their behavior as a leader and whether groups are able to identify such clues and endogenously appoint a "good" leader to solve the dilemma. We find that leaders who promise fairness are more likely to behave fairly, and that followers appoint as leaders those who write more explicitly about fairness and efficiency. However, in their contribution decision, followers focus on the leader's first-move contribution and place less importance on the content of the leader's statements.},
  language  = {en}
}
@techreport{AndresBruttelFriedrichsen2021,
  type      = {Working Paper},
  author    = {Andres, Maximilian and Bruttel, Lisa Verena and Friedrichsen, Jana},
  title     = {The Leniency Rule Revisited: Experiments on Cartel Formation with Open Communication},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {24},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-49169},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-491696},
  pages     = {62},
  year      = {2021},
  abstract  = {The experimental literature on antitrust enforcement provides robust evidence that communication plays an important role for the formation and stability of cartels. We extend these studies through a design that distinguishes between innocuous communication and communication about a cartel, sanctioning only the latter. To this aim, we introduce a participant in the role of the competition authority, who is properly incentivized to judge communication content and price setting behavior of the firms. Using this novel design, we revisit the question whether a leniency rule successfully destabilizes cartels. In contrast to existing experimental studies, we find that a leniency rule does not affect cartelization. We discuss potential explanations for this contrasting result.},
  language  = {en}
}