IDEAS home Printed from
   My bibliography  Save this paper

Platform Divergence, Political Efficiency and the Median Voter Theorem


  • Carrillo, Juan D
  • Castanheira, Micael


The Paper analyses a standard Downsian model of election with two opportunistic parties. We assume that, after choosing their ideological position but before the election takes place, parties can affect the quality of their platforms by exerting some unobservable effort. When voters either (almost) always or (almost) never observe the resulting quality before the election, the standard Median Voter Theorem holds. For the more general case of imperfect observability of quality, however, we show that parties may optimally deviate from the median voter’s bliss point as an implicit commitment to exert high effort (and therefore obtain a high-quality platform). The Paper thus argues that extremist parties are endogenously more committed to their ideas than moderate parties. Moreover, the extra quality implied by the divergence of parties will sometimes offset their worse ideology proposed, in which case the voters’ welfare under divergence is greater than under convergence of platforms. Last, we endogenize the amount of information revealed to voters by assuming that a profit maximizing press collects the news about the quality of parties and sells it to the electorate. We show that the press may collect an amount of information that is excessively high from a social viewpoint.

Suggested Citation

  • Carrillo, Juan D & Castanheira, Micael, 2002. "Platform Divergence, Political Efficiency and the Median Voter Theorem," CEPR Discussion Papers 3180, C.E.P.R. Discussion Papers.
  • Handle: RePEc:cpr:ceprdp:3180

    Download full text from publisher

    File URL:
    Download Restriction: CEPR Discussion Papers are free to download for our researchers, subscribers and members. If you fall into one of these categories but have trouble downloading our papers, please contact us at

    As the access to this document is restricted, you may want to search for a different version of it.

    References listed on IDEAS

    1. Persson, Torsten & Tabellini, Guido, 1999. "Political economics and macroeconomic policy," Handbook of Macroeconomics,in: J. B. Taylor & M. Woodford (ed.), Handbook of Macroeconomics, edition 1, volume 1, chapter 22, pages 1397-1482 Elsevier.
    2. Guesnerie, Roger & Laffont, Jean-Jacques, 1984. "A complete solution to a class of principal-agent problems with an application to the control of a self-managed firm," Journal of Public Economics, Elsevier, vol. 25(3), pages 329-369, December.
    3. Andrea Prat, 2002. "Campaign Advertising and Voter Welfare," Review of Economic Studies, Oxford University Press, vol. 69(4), pages 999-1017.
    4. Michele Polo, "undated". "Electoral competition and political rents," Working Papers 144, IGIER (Innocenzo Gasparini Institute for Economic Research), Bocconi University.
    5. Torsten Persson & Gérard Roland & Guido Tabellini, 1997. "Separation of Powers and Political Accountability," The Quarterly Journal of Economics, Oxford University Press, vol. 112(4), pages 1163-1202.
    6. Bengt Holmström, 1999. "Managerial Incentive Problems: A Dynamic Perspective," Review of Economic Studies, Oxford University Press, vol. 66(1), pages 169-182.
    7. Laffont, Jean-Jacques & Tirole, Jean, 1986. "Using Cost Observation to Regulate Firms," Journal of Political Economy, University of Chicago Press, vol. 94(3), pages 614-641, June.
    8. Micael Castanheira, 2003. "Why Vote For Losers?," Journal of the European Economic Association, MIT Press, vol. 1(5), pages 1207-1238, September.
    9. Timothy Besley & Stephen Coate, 1997. "An Economic Model of Representative Democracy," The Quarterly Journal of Economics, Oxford University Press, vol. 112(1), pages 85-114.
    10. John Ferejohn, 1986. "Incumbent performance and electoral control," Public Choice, Springer, vol. 50(1), pages 5-25, January.
    11. Timothy Feddersen & Wolfgang Pesendorfer, 1997. "Voting Behavior and Information Aggregation in Elections with Private Information," Econometrica, Econometric Society, vol. 65(5), pages 1029-1058, September.
    12. Persson, Torsten & Roland, Gerard & Tabellini, Guido, 1998. "Towards micropolitical foundations of public finance," European Economic Review, Elsevier, vol. 42(3-5), pages 685-694, May.
    13. Rogoff, Kenneth, 1990. "Equilibrium Political Budget Cycles," American Economic Review, American Economic Association, vol. 80(1), pages 21-36, March.
    14. Bernard Caillaud & Jean Tirole, 2002. "Parties as Political Intermediaries," The Quarterly Journal of Economics, Oxford University Press, vol. 117(4), pages 1453-1489.
    15. Caillaud, B. & Tirole, J., 1999. "Party governance and ideological bias," European Economic Review, Elsevier, vol. 43(4-6), pages 779-789, April.
    16. David Strömberg, 2004. "Mass Media Competition, Political Competition, and Public Policy," Review of Economic Studies, Oxford University Press, vol. 71(1), pages 265-284.
    17. David Strömberg, 2004. "Radio's Impact on Public Spending," The Quarterly Journal of Economics, Oxford University Press, vol. 119(1), pages 189-221.
    18. Bengt Holmstrom, 1999. "Managerial Incentive Problems: A Dynamic Perspective," NBER Working Papers 6875, National Bureau of Economic Research, Inc.
    19. Thomas R. Palfrey, 1984. "Spatial Equilibrium with Entry," Review of Economic Studies, Oxford University Press, vol. 51(1), pages 139-156.
    20. John E. Roemer, 1997. "Political-economic equilibrium when parties represent constituents: The unidimensional case," Social Choice and Welfare, Springer;The Society for Social Choice and Welfare, vol. 14(4), pages 479-502.
    Full references (including those not matched with items on IDEAS)


    Citations are extracted by the CitEc Project, subscribe to its RSS feed for this item.

    Cited by:

    1. Fabian Gouret & Guillaume Hollard & Stéphane Rossignol, 2011. "An empirical analysis of valence in electoral competition," Social Choice and Welfare, Springer;The Society for Social Choice and Welfare, vol. 37(2), pages 309-340, July.
    2. repec:hal:journl:hal-00267218 is not listed on IDEAS
    3. Caselli, Francesco & Cunningham, Tom & Morelli, Massimo & Moreno de Barreda, Inés, 2012. "Signalling, Incumbency Advantage, and Optimal Reelection Thresholds," CEPR Discussion Papers 8832, C.E.P.R. Discussion Papers.
    4. Castanheira, Micael & Crutzen, Benoît SY & Sahuguet, Nicolas, 2005. "Party Governance and Political Competition with an Application to the American Direct Primacy," CEPR Discussion Papers 4890, C.E.P.R. Discussion Papers.
    5. Micael Castanheira & Benoît Crutzen & Nicolas Sahuguet, 2010. "The Impact of Party Organization on Electoral Outcomes," Revue économique, Presses de Sciences-Po, vol. 61(4), pages 677-695.
    6. Guillaume Hollard & Stéphane Rossignol, 2008. "An Alternative Approach to Valence Advantage in Spatial Competition," Journal of Public Economic Theory, Association for Public Economic Theory, vol. 10(3), pages 441-454, June.
    7. Francesco Caselli & Tom Cunningham & Massimo Morelli & Inés Moreno de Barreda, 2012. "Signalling, Incumbency Advantage, and Optimal Reelection Rules," CEP Discussion Papers dp1122, Centre for Economic Performance, LSE.

    More about this item


    median voter theorem; moral hazard; party competition;

    JEL classification:

    • D72 - Microeconomics - - Analysis of Collective Decision-Making - - - Political Processes: Rent-seeking, Lobbying, Elections, Legislatures, and Voting Behavior
    • D78 - Microeconomics - - Analysis of Collective Decision-Making - - - Positive Analysis of Policy Formulation and Implementation
    • L15 - Industrial Organization - - Market Structure, Firm Strategy, and Market Performance - - - Information and Product Quality

    NEP fields

    This paper has been announced in the following NEP Reports:


    Access and download statistics


    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:cpr:ceprdp:3180. See general information about how to correct material in RePEc.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (). General contact details of provider: .

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service hosted by the Research Division of the Federal Reserve Bank of St. Louis . RePEc uses bibliographic data supplied by the respective publishers.