dynamics of brand competition effects of unobserved social networks brand competition is modelled using an agent based approach in order to examine the long run dynamics of market structure and brand characteristics a repeated game is designed where myopic firms choose strategies based on beliefs about their rivals and consumers consumers are heterogeneous and can observe neighbour behaviour through social networks although firms do not observe them the social networks have a significant impact on the emerging market structure presence of networks tends to polarize market share and leads to higher volatility in brands yet convergence in brand characteristics usually happens whenever the market reaches a steady state scale free networks accentuate the polarization and volatility more than small world or random networks unilateral innovations are less frequent under social networks

new microfoundations for the aggregate matching function empirical studies of the aggregate labor market matching function have favored a cobb douglas functional form for which there are no microfoundations in the existing literature i present a new model for the matching process based on a telephone line poisson queuing process which unlike other microeconomic approaches can be integrated directly into standard theoretical search models this implies a ces matching function approximately cobb douglas when search costs are approximately linear the model allows empirical estimates of matching function parameters to be interpreted in terms of the costs and benefits of search

a search interpretation of male female wage differentials a general equilibrium search framework is used to examine the role of gender differences in labor market behavior patterns e g quit rates for personal reasons in determining gender wage differentials for samples of high school and college graduates from the national longitudinal survey of youth nlsy these behavioral patterns are found to be significantly different across the sexes and account for 20 30 of the wage differentials in particular they play a key role in explaining the male female wage differential that remains after controlling for the gender composition across occupations

the emergence of generalized exchange the existence of generalized exchange characterized by unilateral resource giving has been a puzzle when we assume rational actors because free riding can occur this article first identifies pure generalized exchange in which each actor gives resources to the recipient s of his choice then it proposes the fairness based selective giving strategy an actor adopting this strategy selects a recipient whose behaviors satisfy her criterion of fairness provided perfect information is given the results of evolutionary simulation show that pure generalized exchange can emerge among egoists without collective norms even in societies in which individuals have information only about their immediate neighbors

strategic delay in bargaining with two sided uncertainty the role of strategic delay is analyzed in an infinite horizon alternating offer model of bargaining a buyer and seller are engaged in the trade of a single object both bargainers have private information about their own preferences and are impatient in that delaying agreement is costly an equilibrium is constructed in which the bargainers signal the strength of their bargaining positions by delaying prior to making an offer a bargainer expecting large gains from trade is more impatient than one expecting small gains and hence makes concessions earlier on trade occurs whever gains from trade exist but due to the private information only after costly delay panmunjom korea upi the american general and the north korean general glared at each other across the table and the only sound was the wind howling across the barren hills outside their hut maj gen james b knapp negotiator for the united nations command unc was waiting for maj gen ri choonsun of the democratic people s republic of north korea to propose a recess they sat there arms folded for 42 hours not a word finally gen ri got up walked out and drove away evening bulletin philadelphia 11 april 1969

social contacts and occupational choice social contacts help workers to find jobs but those jobs need not be in the occupations where workers are most productive hence social contacts can generate mismatch between a worker s occupational choice and his comparative productive advantage thus economies with dense social networks can exhibit apparently low labor force quality and as a result low returns to firms investment and depressed aggregate productivity we employ us and european data for the 1990 s to test the key prediction that social contacts distort workers occupational choices in a direction that reduces their apparent productivity we find that the use of social contacts helps find jobs one to two months sooner but leads to individual wage discounts of 5 to 7 and produces negative externalities on aggregate productivity

job information networks neighborhood effects and inequality this paper explores the theoretical and empirical literature to examine the use by different social groups of informal sources of information provided by friends relatives and acquaintances during job search and its consequences for the job market it also addresses the role of network structure and size the resource endowments of contacts and nature of the links between contacts to explain differences in the effects of job information networks in doing so the paper also turns to the sociology literature on job information networks and provides an economic perspective on such sociological concepts as strong versus weak ties inbreeding distance from structural holes etc the paper distinguishes between models of exogenous job information networks that is where individuals obtain job related information through a given social structure and endogenous job information networks which are social networks that result from individuals uncoordinated actions the paper pays special attention to such issues as physical and social proximity and sharing of information and discusses them in the context of the recent social interactions and neighborhood effects literature finally the paper outlines a model that integrates job information networks where interactions occur in business cycle frequencies with the dynamics of human capital formation which include the joint effects of parental community and neighborhood human capital and are set in life cycle frequencies for the purpose of organizing suggestions for future research and examining earned income inequality

why are similar workers paid differently the role of social networks abstract 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 within our framework wage dispersion arises endogenously as the consequence of the dynamics of networks firms strategies and wage bargaining we show that networks induce new search externalities which shape the dynamics of the labor market our endogenous framework allows us to quantify these effects

production strategies under environmental constraints continuous time model with concave costs abstract the aim of this paper is to investigate how environmental policies in the form of emission charges or emission limits affect the production inventory decisions of a firm our framework applies control theory to analyze optimal production policies the paper modifies the results of wirl european journal of operational research 55 1991 191 to the case of concave production costs

hiring through referrals abstract an equilibrium search model of the labor market is combined with a social network the key features are that the workers network transmits information about jobs and that wages and firm entry are determined endogenously empirically the inter industry variation in aggregate matching efficiency is attributed to variation in referral use the model predicts that the efficiency of the aggregate matching function is pro cyclical which is consistent with empirical evidence

networks and farsighted stability the main contribution of this paper is to provide a framework in which the notion of farsighted stability for games introduced by chwe 1994 can be applied to directed networks in particular we introduce the notion of a supernetwork a supernetwork is made up of a collection of directed networks the nodes and uniquely represents via the arcs connecting the nodes agent preferences and the rules governing network formation by reformulating chwe s basic result on the nonemptiness of farsightedly stable sets we show that for any supernetwork i e for any collection of directed networks and any collection of rules governing network formation there exists a farsightedly stable directed network we also introduce the notion of a nash network relative to a given supernetwork as well as the notions of symmetric nonsimultaneous and decomposable supernetworks to illustrate the utility of our framework we present several examples of super networks compute the farsightedly stable networks and the nash networks

nonlinear persistence and partial insurance income and consumption dynamics in the psid in this paper we highlight the importance of the psid in understanding income dynamics and consumption insurance we explore the nonlinear nature of income shocks and describe a new quantile based panel data framework for income dynamics in this approach the persistence of past income shocks is allowed to vary according to the size and sign of the current shock the model provides a good match with data and we confirm the results on population register data from norway using the enhanced consumption and asset data in the psid nonlinear persistence is shown to have key implications for consumption insurance

networks in labor markets wage and employment dynamics and inequality we present a model of labor markets that accounts for the social network through which agents hear about jobs we show that both wages and employment are positively associated a strong form of correlation across time and agents we also analyze the decisions of agents regarding staying in the labor market or dropping out if there are costs to staying in the labor market then networks of agents that start with a worse wage status will have higher drop out rates and there will be a persistent differences in wages between groups according to the starting states of their networks

the effects of social networks on employment and inequality we develop a model where agents obtain information about job opportunities through an explicitly modeled network of social contacts we show that employment is positively correlated across time and agents moreover unemployment exhibits duration dependence the probability of obtaining a job decreases in the length of time that an agent has been unemployed finally we examine inequality between two groups if staying in the labor market is costly and one group starts with a worse employment status then that group s drop out rate will be higher and their employment prospects will be persistently below that of the other group

search method use by unemployed youth this article presents a search model which shows that search method choices should be related to their costs and expected productivities as well as to nonwage income and wage offer distributions the empirical evidence then shows that the most frequently used search methods i e friends and relatives and direct applications without referral are also the most productive in generating offers and acceptances the number of methods used is affected by factors that presumably reflect opportunities as well as income sources and needs specific methods are chosen in a manner that generates positive average effects on outcomes for those using them

farsighted network formation this paper studies a model of dynamic network formation when individuals are farsighted players evaluate the desirability of a current move in terms of its consequences on the entire discounted stream of payoffs we define a concept of equilibrium which takes into account farsighted behavior of agents and allows for limited cooperation amongst agents we show that an equilibrium process of network formation exists we also show that there are valuation structures in which no equilibrium strategy profile can sustain efficient networks we then provide sufficient conditions under which the equilibrium process will yield efficient outcomes

old boy networks as screening mechanisms this paper studies a fulfilled expectations equilibrium in situations in which intermediaries provide personal opinions on the likelihood of success of personnel projects or investments each referee must recommend some candidates from a group of people about whom he has private information the employer uses the recommendations to choose the workers using his expectations about the quality of the recommended and the nonrecommended applicants although the referees use their information strategically the competition among them produces optimal use of the information in the sense that employers make the same choices in equilibrium as they would if they had the same information as the referees

the empirical content of the job search model labor mobility and wage distributions in europe and the us abstract job search models of the labor market hypothesize a very tight correspondence between the determinants of labor turnover and individual wage dynamics on one hand and the determinants of wage dispersion on the other this paper offers a systematic examination of whether this correspondence is present in the data by estimating a rudimentary partial equilibrium job search model on a three year panel of individual worker data covering 10 european countries and the u s we find that our basic job search model fits the data surprisingly well this also allows us to point at a number of interesting empirical regularities about wage distributions our results suggest that cross sectional data on individual wages contain the basic information needed to obtain a reliable measure of the magnitude of labor market frictions as measured by a parameter of the canonical job search model finally we use our results in a cross country comparison of the intensity and nature of job to job turnover we arrange countries into two different groups according to their turnover intensity we further show that the nature of job to job turnover is very different between those two groups turnover is predominantly voluntary in low turnover countries whereas it is to a large extent involuntary in high turnover countries

on delay in bargaining with one sided uncertainty recently attention has been given to a model of two person bargaining in which the parties alternate making offers and there is uncertainty about the valuation of one party the purpose of the analysis has been to identify delay to agreement with a screening process where agents with relatively lower valuations distinguish themselves by waiting longer to settle we point out a fundamental difficulty with this program by demonstrating that the assumptions used in the literature allow for delay only in so far as the time between offers is significant

some contacts are more equal than others informal networks job tenure and wages the explanation typically given for longer tenure among workers who use informal contacts to find jobs is that relatives and friends reduce uncertainty about the quality of the match between worker and employer an alternative explanation is that workers rely on informal information sources as a last resort such workers remain at their current jobs mainly because they have few alternative choices rather than because of better match quality this article shows that the two different explanations are simultaneously valid for different types of contacts and can account for differences in the wage effects of job contacts

strategic delay in bargaining this paper analyses a bargaining model with incomplete information in which the time between offers is an endogenous strategic variable we find equilibria involving a delay to agreement that is due to the use of strategic time delay by bargainers to signal their relative strength under some specifications of the parameters delay is present in the unique sequential equilibrium whose beliefs satisfy one intuitive restriction this delay does not vanish as the minimal time between offers becomes small

matchmaker matchmaker the effect of old boy networks on job match quality earnings and tenure firms often view job applicant referrals from current employees as more informative than direct applications or referrals through formal labor market intermediaries such as placement firms we argue that old boy networks reduce employers uncertainty about worker productivity using jovanovic s job matching model we show that workers hired through the old boy network should 1 earn higher initial salaries 2 experience lower subsequent wage growth on the job and 3 stay on the job longer than otherwise comparable workers hired from outside the network we find considerable support for this theory using data from the 1972 survey of natural and social scientists and engineers