Expert Information and Majority Decisions

==notes by yinung==
又出現有關 group decision 的研究:
* 專家意見的影響 (在人數多的委員會不佳)
Date: 2015-09-23
By: Kohei Kawamura
Vasileios Vlaseros
This paper shows theoretically and experimentally that hearing expert opinions can be a double-edged sword for collective decision making. We present a majoritarian voting game of common interest where committee members receive not only private information, but also expert information that is more accurate than private information and observed by all members. In theory, there are Bayesian Nash equilibria where the committee members’ voting strategy incorporates both types of information and access to expert information enhances the efficiency of the majority decision. However, there is also a class of potentially inefficient equilibria where a supermajority always follow expert information and the majority decision does not aggregate private information. In the laboratory, the majority decisions and the subjects’ voting behaviour were largely consistent with those in the class of inefficient equilibria. We found a large efficiency loss due to the presence of expert information especially when the committee size was large. We suggest that it may be desirable for expert information to be revealed only to a subset of committee members.
Keywords: committee decision making, voting experiment, expert information, strategic voting
JEL: C92 D72 D82

Private Contracts in Two-Sided Markets

Date: 2015-09
By: Gaston Llanes (Escuela de Administracion, Pontificia Universidad Catolica de Chile)
Francisco Ruiz-Aliseda (Escuela de Administracion, Pontificia Universidad Catolica de Chile)
We study a two-sided market in which a platform connects consumers and sellers, and signs private contracts with sellers. We compare this situation with a two-sided market with public contracts. We find that the platform provider sets positive (negative) royalties to sellers and earns a negative (positive) markup on consumers when contracts are private (public). Thus, private contracting has a significant effect on the price structure. Private contracting leads to lower platform profits, consumer surplus, and social welfare. We study the welfare effects of most-favored-nation clauses, price-forcing contracts, and integration with sellers; and relate our results with the agency model of sales. Our results indicate that enhancing the market power of a dominant platform over sellers may increase welfare because it acts as a commitment device for inducing lower seller prices, mitigating the hold-up problem borne by consumers when they cannot observe sellers’ contracts.
Keywords: Two-Sided Markets; Platforms; Vertical Relations; Most-Favored Nation; Price-Forcing Contracts; Resale Price Maintenance; Integration; Agency Model of Sales
JEL: L12 L14 L42

Risk taking and information aggregation in groups

==notes by yinung==
reverse confirmation bias:
* 決策者對於來自於其他人的且和自己所獲看法相同之私有訊息, 所放的權重較少; 反之, 對和自己所獲看法「衝突」之私有訊息, 所放的權重較多。
they place less weight on information from others that agrees with their private signal and more weight on conflicting information.
* 在 group 分享訊息但不溝通的決策情境中, 此現象會減少…
Date: 2015
By: Spiro Bougheas
Jeroen Nieboer
Martin Sefton
We report a controlled laboratory experiment examining risk-taking and information aggregation in groups facing a common risk. The experiment allows us to examine how subjects respond to new information, in the form of both privately observed signals and signals reported from others. We find that a considerable number of subjects exhibit ‘reverse confirmation bias’: they place less weight on information from others that agrees with their private signal and more weight on conflicting information. We also find a striking degree of consensus when subjects make decisions on behalf of the group under a random dictatorship procedure. Reverse confirmation bias and the incidence of consensus are considerably reduced when group members can share signals but not communicate.
Keywords: Group behaviour; teams; decision making; risk; experiment
JEL: C91 C92 D71 D80

Econometrics of network models

Date: 2015-09
By: Áureo de Paula (Institute for Fiscal Studies and University College London)
In this article I provide a (selective) review of the recent econometric literature on networks. I start with a discussion of developments in the econometrics of group interactions. I subsequently provide a description of statistical and econometric models for network formation and approaches for the joint determination of networks and interactions mediated through those networks. Finally, I give a very brief discussion of measurement issues in both outcomes and networks. My focus is on identification and computational issues, but estimation aspects are also discussed.

Public Goods in Endogenous Networks

Date: 2015-10-21
By: Markus Kinateder (​University of Navarra)
Luca Paolo Merlino (Universit e libre de Bruxelles)
In this paper we study a local public good game in an endogenous network with heterogeneous agents. We consider two specifications, in which different networks arise. When agents differ in the cost of acquiring the public good, active agents form hierarchical complete multipartite graphs; yet, better types need not have more neighbors. When agents have heterogeneous benefits from the public good, nested split graphs in which investment need not be monotonic in type emerge. In large societies, few agents are active and the network dampens inequality.
Keywords: public goods,
JEL: C72 D00 D85 H41

Trading in Networks: a Classroom Experiment

==noted by yinung==
分組, 在圈形的網路 topoloty 中, 隨機選兩組進行貿易, 但 transport 經過各組 node 時要付費
  • S. Choi, A. Galeotti, S. Goyal.Trading in networks: theory and experiments, -Cambridge-INET Working Paper, 2014
  • M. Kosfeld. Economic Networks in the Laboratory: A Survey, Institute for Empirical Research
    in Economics, University of Zurich, 2015.
Date: 2015-10
By: Paul Johnson (Department of Economics and Public Policy, University of Alaska Anchorage)
Qiujie Zheng (Department of Economics and Public Policy, University of Alaska Anchorage)
This paper describes a classroom experiment that demonstrates coordination and competition between traders in a network. Students test theoretical predictions concerning the emergence of equilibrium and the division of surplus between buyers and sellers. The experiment is appropriate for use in teaching intermediate microeconomics, industrial organization, transportation economics and game theory.
Keywords: Experimental Economics, Classroom Experiment, Trading in Networks
JEL: A22 B21 C92