We develop and estimate an equilibrium job search model of worker careers, allowing for human capital accumulation, employer heterogeneity and individual-level shocks. Monthly wage growth is decomposed into the contributions of human capital and job search, within and between jobs. Human capital accumulation is found to be the most important source of wage growth in early phases of workers' careers, but is soon surpassed by search-induced wage growth. Conventional measures of the returns to tenure hide substantial heterogeneity between different workers in the same firm and between similar workers in different firms.

Standard-Nutzungsbedingungen:Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden.Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen.Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. Terms of use: Documents in On the Efficiency of Job Search with Social NetworksPierre Cahuc François Fontaine The Institute for the Study of Labor (IZA) in Bonn is a local and virtual international research center and a place of communication between science, politics and business. IZA is an independent, nonprofit limited liability company (Gesellschaft mit beschränkter Haftung) supported by the Deutsche Post AG. The center is associated with the University of Bonn and offers a stimulating research environment through its research networks, research support, and visitors and doctoral programs. IZA engages in (i) original and internationally competitive research in all fields of labor economics, (ii) development of policy concepts, and (iii) dissemination of research results and concepts to the interested public. The current research program deals with (1) mobility and flexibility of labor, (2) internationalization of labor markets, (3) welfare state and labor market, (4) labor markets in transition countries, (5) the future of labor, (6) evaluation of labor market policies and projects and (7) general labor economics. D I S C U S S I O N P A P E R S E R I E SIZA Discussion Papers often represent preliminary work and are circulated to encourage discussion. Citation of such a paper should account for its provisional character. A revised version may be available on the IZA website (www.iza.org) or directly from the author. ABSTRACT On the Efficiency of Job Search with Social NetworksThis paper provides a simple matching model in which unemployed workers and employers can be matched together through social networks and through more efficient, but also more costly, methods. In this framework, decentralized decisions to utilize social networks in the job search process can be inefficient and give rise to multiple equilibria for some parameters values. More precisely, in a decentralized equilibrium, social networks can be over-utilized, with respect to an efficient allocation, in some circumstances and under-utilized in others. Moreover, the existence of different job search methods can give rise to a higher job search intensity than the efficient one. This is in sharp contrast with the standard result, derived in matching models, according to which search intensity is always too low if not efficient. Eventually, in the presence of different job search methods, conditional unemployment benefits hikes can improve welfare when individuals are risk neutral.JEL Cl...

Standard-Nutzungsbedingungen:Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden.Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen.Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. The Institute for the Study of Labor (IZA) in Bonn is a local and virtual international research center and a place of communication between science, politics and business. IZA is an independent nonprofit company supported by Deutsche Post World Net. The center is associated with the University of Bonn and offers a stimulating research environment through its research networks, research support, and visitors and doctoral programs. IZA engages in (i) original and internationally competitive research in all fields of labor economics, (ii) development of policy concepts, and (iii) dissemination of research results and concepts to the interested public. Terms of use: Documents in D I S C U S S I O N P A P E R S E R I E SIZA Discussion Papers often represent preliminary work and are circulated to encourage discussion. Citation of such a paper should account for its provisional character. A revised version may be available directly from the author. We provide a matching model where identical workers are embedded in ex-ante identical social networks. Job arrival rate is endogenous and wages are bargained. We study the evolution of networks over time and characterize the equilibrium distribution of unemployment rates across networks. We emphasize that wage dispersion arises endogenously as the consequence of the dynamics of networks, firms' strategies and wage bargaining. Moreover, contrary to a generally accepted idea, social networks do not necessary induce stickiness in unemployment dynamics. Our endogenous matching technology shows that the effects of networks on the dynamics mostly hinge on search externalities. Our endogenous framework allows us to quantify these effects.JEL Classification: E24, J64, J68

Our main objective in this paper is to quantify the relative importance of human capital accumulation and imperfect labor market competition in shaping individual labor earnings profiles over the working life. We contribute to the empirical literature on wage equations along three broad dimensions.The first one relates to Mincer's (1974) original specification of log-earnings as a function of individual schooling and experience. In their review of Mincer's stylized facts about postschooling wage growth in the United States, Rubinstein and Weiss (2006) list human capital accumulation and job search as two of the main driving * Bagger: Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK, and CAP (e-mail: jesper.bagger@rhul.ac.uk); Fontaine: Université de Lorraine, 6 rue des Michottes, 54000 Nancy, France, BETA-CNRS, and CREST-ENSAE (e-mail: francois.fontaine@univ-lorraine.fr); Postel-Vinay: Department of Economics, University College London, Drayton House, 30 Gordon Street, London WC1H 0AX, UK, and Sciences Po, Paris (e-mail: f.postel-vinay@ucl.ac.uk); Robin: Department of Economics, Sciences Po, 28, rue des Saints Pères, 75007 Paris, France, and UCL (e-mail: jeanmarc.robin@sciences-po.fr). We are grateful to three anonymous referees for very detailed and constructive comments. We also wish to thank Joe Altonji, Henning Bunzel, Ken Burdett, Melvyn Coles, and Rune Vejlin, as well as participants in numerous seminars and conferences, for useful comments. The usual disclaimer applies. Bagger and Fontaine gratefully acknowledge financial support from LMDG and CAP, Aarhus University (LMDG is a Dale T.