* Corresponding author. Tel.: #44-171-955-75-17; fax: #44-171-831-18-40. E-mail address: t.mariotti@lse.ac.uk (T. Mariotti). European Economic Review 45 (2001) 1}25 Electoral competition and politician turnover Juan D. Carrillo, Thomas Mariotti* ECARE, Universite & Libre de Bruxelles, 39, avenue Franklin D. Roosevelt, 1050 Bruxelles, Belgium Department of Economics, London School of Economics and Political Science, Houghton Street, WC2A 2AE London, UK Received 1 October 1997; accepted 6 December 1999 Abstract In this paper, we analyze the selection by opportunistic parties of the candidates who run for election. We consider a setting with incomplete but symmetric information about the candidates' abilities, in which electoral campaigns provide voters with additional information about candidates. Parties care only about selecting an appropriate candidate to win the election, while voters elect the best candidate conditional on their information. We "rst argue that in order to defeat an established very good candidate of its rival, a party may favor a new candidate with highly uncertain ability, rather than an established good candidate. Next, we establish that the discrepancy between the objective of parties and the objective of the electorate leads to ine$cient conservatism in the selection of candidates, i.e. each party keeps its incumbents too often from the voters' viewpoint.  2001 Elsevier Science B.V. All rights reserved. JEL classixcation: D72; D81 Keywords: Elections; Candidates; Incentives; Political campaigns 1. Introduction Elections are one of the prominent features of modern democratic societies. It is therefore quite natural that much theoretical attention has been devoted to study their e$ciency properties. Up to now, most studies have focused on the informational asymmetries that may jeopardize the electoral process. Starting 0014-2921/01/$ - see front matter  2001 Elsevier Science B.V. All rights reserved. PII: S 0 0 1 4 - 2 9 2 1 ( 9 9 ) 0 0 0 7 7 - X