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The Informational Effects of Competition and Collusion in Legislative Politics


  • Martimort, David
  • Semenov, Aggey


We use a mechanism design approach to study the organization of interest groups in an informational model of lobbying. Interest groups influence the legislature only by communicating private information on their preferences and not by means of monetary transfers. Interest groups have private information on their ideal points in a one-dimensional policy space and may either compete or adopt more collusive behaviors. Optimal policies result from a trade-off between imposing rules which are non-responsive to the groups' preferences and flexibility that pleases groups better. Within a strong coalition, interest groups credibly share information which facilitates communication of their joint interests, helps screening by the legislature and induces flexible policies responsive to the groups' joint interests (an informativeness effect). Competing interest groups better transmit information on their individual preferences (a screening effect). The socially and privately optimal organization of lobbying favors competition between groups only when their preferences are not too congruent with those of the legislature. With more congruence, a strong coalition is preferred. Finally, within a weak coalition, interest groups must design incentive compatible collusive mechanisms to share information. Such weak coalitions are always inefficient.

Suggested Citation

  • Martimort, David & Semenov, Aggey, 2008. "The Informational Effects of Competition and Collusion in Legislative Politics," MPRA Paper 6989, University Library of Munich, Germany.
  • Handle: RePEc:pra:mprapa:6989

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    Cited by:

    1. Tymofiy Mylovanov & Andriy Zapechelnyuk, 2010. "Decision Rules for Experts with Opposing Interests," Working Papers 674, Queen Mary University of London, School of Economics and Finance.
    2. Zapechelnyuk, Andriy, 2013. "Eliciting information from a committee," Journal of Economic Theory, Elsevier, vol. 148(5), pages 2049-2067.
    3. Rosar, Frank, 2015. "Continuous decisions by a committee: Median versus average mechanisms," Journal of Economic Theory, Elsevier, vol. 159(PA), pages 15-65.
    4. Javier A. Prado Domínguez & Antonio García Lorenzo, 2010. "Competencia e incentivos a la cooperación en la interacción de grupos de interés que pretenden aumentar su influencia política directa: ¿cuál es la importancia de la presión política?," Hacienda Pública Española, IEF, vol. 192(1), pages 105-125, March.
    5. Ricardo Alonso & Isabelle Brocas & Juan D. Carrillo, 2014. "Resource Allocation in the Brain," Review of Economic Studies, Oxford University Press, vol. 81(2), pages 501-534.
    6. Burnett, Johann Caro & Carrasco, Vinicius, 2011. "Coordination and the provision of incentives to a common regulated firm," International Journal of Industrial Organization, Elsevier, vol. 29(5), pages 606-627, September.
    7. Kawamura, Kohei, 2008. "Communication for Public Goods," SIRE Discussion Papers 2008-25, Scottish Institute for Research in Economics (SIRE).
    8. Kohei Kawamura, 2008. "Communication for Public Goods," ESE Discussion Papers 182, Edinburgh School of Economics, University of Edinburgh.
    9. McGee, Andrew & Yang, Huanxing, 2013. "Cheap talk with two senders and complementary information," Games and Economic Behavior, Elsevier, vol. 79(C), pages 181-191.
    10. Robin Boadway & Motohiro Sato, 2008. "Bureaucratic Advice and Political Governance," Journal of Public Economic Theory, Association for Public Economic Theory, vol. 10(4), pages 503-527, August.
    11. Koessler, Frédéric & Martimort, David, 2012. "Optimal delegation with multi-dimensional decisions," Journal of Economic Theory, Elsevier, vol. 147(5), pages 1850-1881.
    12. Andrea Attar & Eloisa Campioni & Gwenael Piaser, 2011. "Information Revelation in Competing Mechanism Games," CEIS Research Paper 205, Tor Vergata University, CEIS, revised 04 Jul 2011.
    13. Mylovanov, Tymofiy & Zapechelnyuk, Andriy, 2013. "Decision rules revealing commonly known events," Economics Letters, Elsevier, vol. 119(1), pages 8-10.
    14. Attar, Andrea & Campioni, Eloisa & Piaser, Gwenaël, 2013. "Two-sided communication in competing mechanism games," Journal of Mathematical Economics, Elsevier, vol. 49(1), pages 62-70.

    More about this item


    Communication Mechanisms; Lobbying; Competition; Coalition; Legislative Politics;

    JEL classification:

    • D72 - Microeconomics - - Analysis of Collective Decision-Making - - - Political Processes: Rent-seeking, Lobbying, Elections, Legislatures, and Voting Behavior
    • D8 - Microeconomics - - Information, Knowledge, and Uncertainty

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