dynamic market models in industrial organization abstract this paper surveys empirical work done on dynamic models of market performance these fall into one of two categories structural models which model how market structure and performance change in response to entry and reduced form models which describe change regardless of how it is brought about a typical example of each type of model is chosen from the literature and simulations are used to draw out the implications of the estimated coefficients both models depict the competitive process in the us economy as being extremely slow

can entry or exit event studies inform horizontal merger analysis evidence from grocery retailing this study estimates how prices change following the entry and exit of grocery retailers we estimate the effects of entry exit by comparing affected markets to a set of unaffected markets using both a difference in difference estimator and a synthetic control estimator we find that entry typically results in reduced prices more surprisingly we find that exit is frequently associated with falling prices our estimated effects of entry on grocery prices are similar in magnitude to estimates of merger price effects in the supermarket industry this finding suggests that entry event studies may be a useful tool for horizontal merger analysis jel l11 l4 l81

a direct mechanism characterization of sequential bargaining with one sided incomplete information we characterize the sequential equilibria of a class of infinite horizon bargaining games with one sided incomplete information when the seller the uninformed party makes all the offers we prove a folk theorem every incentive compatible individually rational direct bargaining mechanism is implementable by sequential equilibria introducing buyer counteroffers eliminates outcomes which are unfavorable to that party as the proportion of buyer offers increases the set of implementable mechanisms shrinks continuously when the proportion reaches one only the single outcome most favorable to the buyer remains thus depending on the offer structure sequentiality may or may not impose restrictions beyond static incentive compatibility

entry exit and performance in airline markets abstract data from the airline industry indicate that 1 entry generally is not induced by price levels substantially above the norm 2 entry reduces fares and increases output and exit increases fares and reduces output and 3 incumbents cut price and maintain output in response to entry and survivors increase both price and output in response to exit these findings cast doubt on the ability of entry to prevent or reverse price increases from anticompetitive mergers

towards a testable model of entry a study of the us manufacturing industries this paper develops a simple model of firms entry decisions fits it to interindustry data and tests hypotheses related to contestability theory it is shown that entry increases with the profit level of incumbents holding fixed the expected losses that the entrant would suffer in the event of exit these expected losses are greater the higher the probability of a predatory incumbent response and the larger the sunk costs that must be committed by the entrant the effects of sunk costs are significant and incumbents are significantly more likely to react aggressively when they are both profitable and concentrated copyright 1990 by the london school of economics and political science

dynamic contracting under adverse selection and renegotiation abstract we study the effects of renegotiation in an infinitely repeated screening model with long term contracts we propose a simple and tractable recursive formulation to study equilibria in which the monopolist s profit is maximized after every history we show that the monopolist sequentially screens high type consumers and characterize second degree price discrimination policies the monopolist s ability to extract rent from high type consumers by distorting the allocation of low type consumers vanishes as all parties become more patient as a result all distortions disappear and the allocation becomes efficient

alcohol consumption and human capital a retrospective study of the literature grossman proposed an individual s health can be viewed as one aspect of their human capital following this line of thought a number of recent papers have reported a positive impact of alcohol consumption on earnings the rationale for the existence of such a relationship is the positive impact of alcohol on physical and mental health we conduct a meta analysis to determine whether such factors as the estimation technique the presence of ex drinkers in the sample possible sample selection bias and publication bias may all contribute to these findings an additional suggestion for the positive relationship between alcohol and wages is the presence of a common set of personality traits that determines drinking behaviour and also leads to higher earnings we examine this relationship by reviewing the literature that investigates if the personality influencing aspects of alcohol consumption influences measures of human capital we also survey the significant body of research that has examined how alcohol consumption has been found to influence educational outcomes and the work force participation of problem drinkers

entry in monopoly market this paper develops new empirical models of market concentration from game theoretic models of entry we construct our models from inequality conditions that describe entrants equilibrium strategies in simultaneous move and sequential move games and use them to study the effects of entry in isolated monopoly markets for new automobiles from estimates of the market size necessary to support one and two dealers we conclude that monopoly dealers do not block the entry of a second dealer we also find that entry does not cause price cost margins to fall by much

contracting with imperfect commitment and noisy communication abstract this paper provides new analytical tools for studying principal agent problems with adverse selection and limited commitment by allowing the principal to use general communication devices we overcome the literature s common but overly restrictive focus on one shot direct communication in addition general communication devices solve two fundamental problems of contracting with imperfect commitment first they allow us to identify the local downward incentive constraints as the relevant ones if the agent s preferences satisfy a single crossing property second we show how one may restrict the cardinality of the message spaces of the communication device an example illustrates our arguments and the suboptimality of one shot direct communication

preying for time the recent antitrust policy literature which seeks to define predatory pricing contains a flood of proposals which have pervasively transformed an entire body of law 1 one theme of this literature is that a readily anticipatable standard should be established so that firms will not fear being sued for normal competitive responses another is that since predation is presumed to be rare the standard should be lax so as to minimize the possibility of stifling competition in the overwhelming majority of more competitive markets perhaps the most striking feature of these arguments is the omission of any analysis of predatory behavior when business firms are sophisticated and rational mcgee i980 pp 295 6 for example points out that predation only pays if the present discounted value of future high prices exceeds the costs of suffering today s low prices but if this is so for the monopolist then why not for the competitor

market structure entry and performance in korea this paper applies a recursive model of structure entry performance with structural feedbacks to sixty two korean manufacturing industries for 1976 81 the results strongly support the market power hypothesis the results also indicate that despite active government intervention the invisible hand is working structure is evolving as expected with high profits leading to entry and consequently lower profits however there is little support for limit pricing hypotheses in this explosively growing economy copyright 1990 by mit press

mutual forbearance in experimental conglomerate markets we conduct economic experiments to gauge the level of cooperation between conglomerate rivals first we run control experiments to observe cooperation between subjects acting as duopolists in one of two markets in the control experiments subject pairs choose a quantity xi or yi from a payoff matrix in a repeated game relatively less cooperation is observed in the y market than in the x market a second series of experiments then combines the two payoff matrices to create a conglomerate setting facing each other in two markets opponents now choose an xi yi pair each period we find that conglomeration encourages more coperation in the y market but less cooperation in the x market time series analysis of our conglomerate subjects choices strongly supports the recent game theoretic propositions in bernheim and whinston 1990

cooperative investments and the value of contracting recent articles have shown that contracts can support the efficient outcome for bilateral trade even in the face of specific investments and incomplete contracting these studies typically considered selfish investments that benefit the investor e g the seller s investment reduces her production costs the authors find very different results for cooperative investments that directly benefit the investor s partner e g the seller s investment improves the buyer s value of the good most importantly if committing not to renegotiate the contract is impossible then contracting has no value i e the parties cannot do better than to abandon contracting altogether in favor of ex post negotiation

contract renegotiation a simple framework and implications for organization theory this paper provides a unifying framework for studying renegotiation of contracts in the presence of asymmetric information we show that interim renegotiation does not constrain the set of contracts attainable with full commitment regardless of whether renegotiation offers are made by the informed or the uninformed agent ex post renegotiation however does constrain the set of attainable contracts these constraints depend on the identity of the agent making the renegotiation offer we then show how the theory of contract renegotiation can provide insights for organization theory specifically we show how decentralization of decision making can be an optimal response to the threat of ex post renegotiation finally we show that our framework can be used to analyse the trade off between internal and external markets

do drinkers earn less theoretical work by becker and others on human capital led initially to empirical research on the determinates of earnings interest in human capital has now spread to other areas especially health this movement is in conjunction with societal concerns regarding the role of diet and environmental factors on human well being and performance following becker 1 and grossman 9 economists expect to find a significant relationship between health and earnings health aspects of human capital have been extensively explored since the early work of grossman 9 10 good health is both beyond the control of the individual exogenous as a result of genetic factors and random events and controllable endogenous through the regulation of activities such as smoking drinking eating exercise and other informed choices this study examines the relation between earnings and drinking curiously little rigorous empirical work has been done on the relation between earnings and drinking irving fisher s claim to the contrary 1 there is little evidence that prohibition led to substantial if any productivity increases although it is established that excessive drinking leads to poor health the empirical evidence regarding earnings and drinking is mixed and inconclusive according to the u s government abusive drinkers earn less in their biennial reports to congress the national institute on alcohol abuse and alcoholism niaaa estimates the economic cost to society of alcohol abuse approximately half of this cost arises from the estimated loss in earnings productivity due to abusive drinking 2 their approach consists of estimating a wage equation which includes human capital variables as well as a dichotomous abusive drinking variable and quantity of alcohol consumed 3 berger and leigh 3 used a sample selection model to test whether drinkers earned more or less than nondrinkers they divided their sample from the 1972 73 quality of employment survey into two categories drinkers and nondrinkers using a sample selection correction estimator hedonic wage regressions for each category and by sex were estimated they found that drinkers moderate and abusive combined earned more than nondrinkers comparisons were then made between wages from each regression with demographic and human capital variables set at

ambivalent investment and the hold up problem in this paper we add to the foundations of incomplete contracting literature we study the hold up problem with ambivalent investment where investment benefits the investing party if ex post the right decision is undertaken but harms the investing party if the wrong decision is made in this context we show that the power of contracts to provide investment incentives depends on three factors the commitment value of contracts the amount of quasirents that the investing party can expect in the case of out of contract renegotiation and the degree of ambivalence of investment first contracts provide first best investment incentives when parties can commit to a contract regardless of the type of investment second with sufficiently ambivalent investment if parties cannot commit not to renegotiate a contract and if the investing party s bargaining power is intermediate contracts cannot improve investment incentives above those provided by no contract in contrast a simple buyer or seller option contract is optimal when the investing party s bargaining power is extreme jel d23 k12 l22

reputation in bargaining and durable goods monopoly this paper analyzes durable goods monopoly in an infinite horizon discrete time game we prove that as the time interval between successive offers approaches zero all seller payoffs between zero and static monopoly profits are supported by subgame perfect equilibria this reverses a well known conjecture of coase alternatively one can interpret the model as a sequential bargaining game with one sided incomplete information in which an uninformed seller makes all the offers our folk theorem for seller payoffs equally applies to the set of sequential equilibria of this bargaining game

concentration potential entry and performance in the airline industry airline markets do not satisfy the theoretical conditions for perfect contestability and theory does not indicate which deviations from perfect contestibilty significantly affect performance thus the effect of potential entry on performance in airline markets is explored empirically the best model for explaining fares is found to be one in which the measure of market concentration takes into account not only the number and size distribution of incumbents but also the number of potential entrants not significantly disadvantaged due to economies of scale and scope the hypothesis that all city pair markets are perfectly contestable is rejected coauthors are richard l johnson andrew s joskow gregory j werden and michael a williams copyright 1989 by blackwell publishing ltd

is there a wage bonus from drinking unobserved heterogeneity examined while the result that drinkers earn more than abstainers has been remarkably persistent only one paper in the literature on drinking and earnings has been written where individual fixed effects are included this study improves the current literature by utilizing a much longer panel and focuses on the low end of drinking while controlling for unobserved heterogeneity with the inclusion of individual specific effects it is found that while ols specifications yield a positive significant coefficient on current drinking even when a rich set of covariates is controlled for including individual fixed effects renders the coefficient statistically insignificant

price reactions to rivals local channel exits in this paper we study the effect of a firm s local channel exits on prices charged by incumbents remaining in the marketplace exits could result in higher prices due to tempered competition or lower prices due to reduced colocation or agglomeration benefits the net effect of these two countervailing forces remains unknown in addition little is known about how this effect could change depending on incumbents geographic locations we address this research gap by examining new car price reactions by incumbent multiproduct automobile dealerships who experience the exit of a chrysler dealership in their local markets we find evidence that the competition effect exceeds the colocation effect prices increase by about 1 318 following an exit relative to the price change in the absence of an exit more important we find that the price increase is lower at dealerships more proximate to the exiting dealership than dealerships farther away for the same set of cars available across these locations this

ex post renegotiation proof mechanism design we study what kind of equilibria of which mechanisms are ex post renegotiation proof eprp i e robust against the possibility of ex post renegotiation under a variety of renegotiation procedures and which social choice functions are eprp implementable in complete information environments with two agents only budget balanced groves allocations are eprp implementable while with three or more agents all ex post efficient allocations are in environments with independent private values essentially only the budget balanced groves in expectations allocations are eprp implementable while with three or more agents and correlated beliefs all ex post efficient allocations are

incumbent positioning as a determinant of strategic response to entry existing research has identified different firm characteristics that determine an incumbent s reaction toward market entrants this study widens the perspective from a firm s absolute attributes to its relative positioning within its competitive environment the hypotheses for the empirical analysis are derived from game theoretic models with either vertical or horizontal product differentiation in each of the two theoretical models two incumbents initially choose very different quality and variety levels respectively and move closer to the center when faced by entry of a competitor from the vertical differentiation model we predict a stronger price reduction by high quality firms in our empirical analysis we are using a novel dataset of the high quality restaurant market in germany to test the theoretical findings while the hypotheses with respect to adjustments of prices and varieties are supported we do not find empirical evidence for the predicted quality adjustment

adverse selection and renegotiation in procurement as was shown by dewatripont optimal long term contracts are generally not sequentially optimal the parties ex post renegotiate them to their mutual advantage this paper fully characterizes the equilibrium of a simple two period procurement situation and studies the extent to which renegotiation reduces ex ante welfare i a central result is that like in the non commitment case the second period allocation is optimal for the principal conditionally on his posterior beliefs about the agent ii the first period allocation exhibits an increasing amount of pooling when the discount factor grows iii with a continuum of types it is never optimal to induce full separation the paper also analyzes whether renegotiated long term contracts yield outcomes resembling those under either unnegotiated long term contracts or a sequence of short term contracts and it links the analysis with the multiple unit durable good monopoly problem

contract design and non cooperative renegotiation abstract we study a contract design setting in which the contracting parties cannot commit not to renegotiate previous contract agreements in particular we characterize the outcome functions that are implementable for an uninformed principal and an informed agent if having observed the agent s contract choice the principal can offer a new menu of contracts in its place an outcome function can be implemented in this setting if and only if it is optimal for the principal for some belief over agent types which is more pessimistic in the sense of the likelihood ratio order than the prior furthermore the outcome function cannot be too sensitive to variations in the agent s type we show that the direct revelation mechanism which implements such a function when renegotiation can be prevented will also implement it in any equilibrium when it cannot so the standard contract is robust to renegotiation

the dynamics of incentive contracts the paper studies a simple two period principal agent model in which the principal updates the incentive scheme after observing the agent s first period performance the agent has superior information about his ability the principal offers a first period incentive scheme and observes some measure of the agent s first period performance cost or profit which depends on the agent s ability and unobservable first period effort the relationship is entirely run by short term contracts in the second period the principal updates the incentive scheme and the agent is free to accept the new incentive scheme or to quit the strategies are required to be perfect and updating of the principal s beliefs about the agent s ability follows bayes rule the central theme of the paper is that the ratchet effect leads to much pooling in the first period first for any first period incentive scheme there exists no separating equilibrium second when the uncertainty about the agent s ability is small the optimal scheme must involve a large amount of pooling the paper also gives necessary and sufficient conditions for the existence of partition equilibria and looks at the effect of cost uncertainty

participation constraints in adverse selection models abstract this paper characterizes the optimal contract offered by an uninformed principal to an informed agent when the latter s reservation utility depends on his type the informational rent is nonmonotonic so that interior types may have a vanishing rent or be excluded from trade the paper identifies conditions for the optimal contract to be separating to be nonstochastic and to induce full participation it also discusses the nature of the solution when bunching occurs the results are applied to nonlinear pricing under price cap regulation and bypass competition and to competition in nonlinear pricing journal of economic literature classification numbers d82 d42 d23 d78 l51 l15

alcohol taxes and labor market outcomes abstract we present reduced form estimates of the effect of alcohol taxes on employment weekly work hours and wages the reduced form estimates are meaningful in two ways first they provide estimates of the effect of an important public policy tool alcohol taxes and second they can be used to evaluate hypotheses about the structural effects of alcohol use on labor market outcomes estimates indicate that there is a weak and indeterminate relationship between alcohol taxes and labor market outcomes this implies that alcohol use does not adversely affect labor market outcomes and is inconsistent with findings from previous studies

complexity and renegotiation a foundation for incomplete contracts the paper considers a hold up model where only one of n future trading opportunities will prove to be efficient and where ex post renegotiation of the ex ante contract cannot be prevented as the environment becomes more complex n the outcome under any message contingent long term contract converges to that of the incomplete contracting model where trade is contractible ex post but not ex ante when trades are costly to describe both ex ante and ex post the incomplete contracting result is extended to a broader class of environments

potential competition in the deregulated airlines using a new and unique data set this paper applies a systems approach to the study of potential competition prices and entry relations in airline city pair markets consistent with limit pricing models future entry is directly influenced by current prices current prices thus appear to provide an important signal to potential entrants about the probability of profitable entry while results indicate the existence of barriers to entry these barriers appear to have no independent effects on price beyond there effect on actual competition through increases in concentration copyright 1990 by mit press

multimarket contact and collusive behavior traditional analyses of industrial behavior typically link the exercise of market power in an industry to internalfeatures such as demand conditions concentration and barriers to entry nevertheless some economists have remained concerned that external factors such as contact across markets may also play a significant role in determining the level of competitiveness in any particular industry in this article we examine the effect of multimarket contact on the degree of cooperation that firms can sustain in settings of repeated competition we isolate conditions under which multimarket contact facilitates collusion and show that these collusive gains are achieved through modes of behavior that have been identified in previous empirical studies of multimarketfirms

postentry investment and market structure in the chemical processing industries this article analyzes the investment response of incumbents to new entry in 39 chemical product industries the behavior of incumbents in highly concentrated industries differed from that of incumbents in low concentration industries in concentrated industries incumbents increased their rate of investment following entry but reduced investment to accommodate capacity expansions made by other incumbents this asymmetric response did not arise in less concentrated industries significant excess capacity existed in concentrated industries following entry but there is little evidence that incumbents built such capacity as a deterrent before entry thus the results support mobility deterrence theories rather than the conventional excess capacity deterrence argument

estimation of a model of entry in the airline industry this paper considers the effect of an airline s scale of operation at an airport on the profitability of routes flown out of that airport the empirical methodology uses the entry decisions of airlines as indicators of underlying profitability the results extend the empirical literature on airport presence by providing a new set of estimates of the determinants of city pair profitability these estimates imply that city pair profits increase in airport presence and decrease rapidly in the number of entering firms the literature on empirical models of oligopoly entry is also extended via a focus on the role of differences between firms

the effect of alcohol use on wages 1988 the effect of alcohol use on wages applied economics vol 20 no 10 pp 1343 1351

contract renegotiation and coasian dynamics consider a long term relationship between a seller and a buyer whose valuation for a per period service or a durable good is private as trade progresses the valuation will be partially revealed and it may be impossible for the parties to commit ex ante not to take advantage of this we analyse this situation first by supposing that the parties can sign a sequence of short term contracts and secondly by supposing that they can sign a long term contract but cannot commit not to renegotiate it later we find a close relationship in the second case between the optimal long term contract and the non commitment outcome in the standard coasian durable good model our results also have implications for hidden information principal agent models

contestable markets an uprising in the theory of industry structure presents a transcript of the presidential address delivered at the 94th meeting of the american economic association on december 29 1981 discussion of developments in the theory of industry structure welfare attributes of contestable markets behavior characteristics of oligopoly equilibrium intertemporal vulnerability to inefficient entry ebsco

contracting with imperfect commitment and the revelation principle the single agent case this paper extends the revelation principle to environments in which the mechanism designer cannot fully commit to the outcome induced by the mechanism we show that he may optimally use a direct mechanism under which truthful revelation is an optimal strategy for the agent in contrast with the conventional revelation principle however the agent may not use this strategy with probability one our results apply to contracting problems between a principal and a single agent by reducing such problems to well defined programming problems they provide a basic tool for studying imperfect commitment

gender differences in labor market effects of alcoholism little is known about the role of specific health problems in affecting labor market productivity even less is known about gender differences in the labor market effects of such health problems current knowledge of health effects is based largely on samples composed exclusively of men a common practice in both economics and health research in the latter case even a congressional mandate to incorporate females in study samples is reputed to have had little effect patricia schroeder 1990 in this study we attempt to determine the structure of gender differences in labor market responses to alcoholism we use a relatively new data source that allows such comparisons by gender in a large community based sample previous studies have established that there are significant gender differences in labor market behavior differences in prevalence rates of alcoholism by gender are also well established it is estimated that 3 percent of females are currently suffering from alcoholism and twice that many have exhibited symptoms at some time for males the numbers are 10 and 20 percent respectively there is some medical evidence to indicate that physiologically women and men respond differently to alcohol for example a recent study suggests that women have greater vulnerability to the acute and chronic health conditions associated with alcoholism mario frezza et al 1990

a pint a day raises a man s pay but smoking blows that gain away this paper studies the wage effects of the use of alcohol and tobacco the analysis based on a recent survey in the netherlands shows that for males the use of tobacco has a negative wage effect of about 10 while the use of alcohol has a positive wage effect of about the same size the wages of females are not affected by smoking and drinking

federal funding and the level of private expenditure on basic research economists have long been interested in questions concerning the role of government in stimulating private sector innovation in the late 1950s blank and stigler 2 asked in particular whether government funded industrial research and development r d activity was likely to stimulate or substitute for private sector expenditure on r d a number of studies have since addressed this issue and most conclude in favor of the existence of a positive relationship between federal r d expenditures and the level of private r d investment leyden and link 8 have provided a theoretical rationale for this observed complementarity they suggest that federallyfunded industrial r d activity may generate knowledge spillovers and other infratechnology that may raise the productivity of inputs into private r d r d is a heterogeneous activity and a question which has received relatively little attention in the literature is the extent to which the apparent complementarity between federal and private industrial r d spending holds for the different components of firms r d budgets cross section evidence on this issue produced by link 13 suggests that

renegotiation proof implementation and time preferences this paper explores how the requirement that the implementation of contracts be renegotiation proof affects the set of contracts that can be implemented in a seller buyer scenario in which the information regarding the agents valuations is nonverifiable this paper explicitly adds a time dimension to an implementa tion problem and introduces a natural criterion of renegotiation proofness for the case of time consuming renegotiation the main insight gained is that the addition of the time dimension enlarges significantly the set of contracts that can be implemented in a renegotiation proof manner jel c70 d23 this paper explores how the requirement that the implementation of contracts be renegotiation proof affects the set of con tracts that can be implemented in a seller buyer scenario in which the informa tion regarding the agents valuations is non verifiable the paper s main contributions are that first it explicitly adds a time di mension to an implementation problem and second it introduces a natural criterion of renegotiation proofness for the case of time consuming renegotiation for concreteness the discussion will be conducted in the context of the following example there are two agents a seller and a buyer who sign a contract for the sale of one unit in the future their valuations for the unit denoted by s and b respectively are not known when they sign the contract they become known to both parties after the contract is signed and before it is imple mented thus when it comes to implement ing the contract the parties information is complete but it is assumed to be nonverifi able i e not observable to third parties such as a court 1 when they sign the con tract the parties want to specify for any possible realization of the valuations s b whether or not there will be trade and the price p s b at which it will take place the contract describes the procedure that will be followed after the valuations are real ized the purpose of this procedure is to make sure that the original intentions of the parties are indeed carried out the idea is that the steps laid out in the contract are independent of s b and hence are en forceable by a third party or by a social convention in game theoretic terms a contract specifies a game form that imple ments the function p in the sense that for all s and b p s b is the resulting game s unique subgame perfect equilibrium out come in the context of this scenario we shall investigate the set of price functions p s b that can be so implemented by a contract and examine how this set is affected by the requirement that the contract be renegotia

excess capacity and limit pricing an empirical test entry may be inhibited by expectations that incumbents have lower marginal costs incumbents may be able to use limit pricing or excess capacity to further this expectation we construct an empirical model of oligopoly capacity and pricing decisions and of entrant responses the results support the hypothesis that both lower prices and greater excess capacity inhibit entry they further support limit pricing but provide no evidence that oligopolies deliberately install excess capacity to deter entry the results suggest however that limit pricing firms may exploit the entry inhibiting effects of unintended excess capacity by raising their limit prices

airline mergers airport dominance and market power effects of northwestrepublic and twaozark mergers on fares at minneapolisst paul and st louis

employment unemployment and problem drinking the misuse of alcohol is estimated to result in enormous economic costs composed largely of reduced labor market productivity however there has been debate on this issue the purpose of this paper is to help to resolve this debate by presenting sound structural estimates of the relationship between measures of problem drinking and of employment and unemployment the analysis is based on the 1988 alcohol supplement of the national health interview survey we find that for both men and women problem drinking results in reduced employment and increased unemployment

optimal information transmission in a holdup problem this article examines the optimal contract in a bilateral trade model with unobservable relationship specific investment and renegotiation in such a setting a contract plays an additional role that it does not have in the standard holdup model namely that of transmitting information between the parties the article shows that a partial disclosure contract may be optimal and describes the optimal contract if the investment is cooperative and the information between the trading parties is asymmetric the optimal contract generally cannot result in the first best but dispensing with either of these assumptions makes the first best achievable

job search and network composition implications of the strength of weak ties hypothesis workers find jobs through personal contacts weak and strong ties and formal sources alternative formulations of the strength of weak ties hypothesis suggest 1 weak ties relay job offers more frequently than strong ties or 2 weak tie offers are drawn from a better distribution a formal model shows that both formulations imply a correlation between network composition and a job seeker s minimum acceptable wage however the use of a weak tie is never associated with higher expected wages under the firstformulation and is only sometimes associated with higher expected wages under the secondformulation these results suggest that researchers shouldfocus on job seekers network structures

adolescent alcohol use sociability and income as a young adult we use data from the national longitudinal survey of adolescent health add health to study how sociability and adolescent alcohol use impact personal income as a young adult we find that factors which enhance not only individual sociability but also social interaction at the community level are positively linked to future earnings of adolescents adolescents whose friends and friends of friends have greater sociability reap long term labour market rewards into adulthood after adjusting for individual and community sociability the effect of teenage alcohol consumption on labour market earnings as young adults is reduced our results suggest that earnings premiums associated with adolescent alcohol consumption may be partially explained by social network dynamics

optimal oligopoly pricing and the threat of entry in earlier work we tested stochastic dynamic limit pricing using u s data we replicate these tests using canadian data the results are weak but consistent with the earlier tests along the way we deal with several methodological problems how does the new rational limit pricing relate to the test how might oligopoly influences be integrated into limit pricing how should existing concentration affect entrant behavior might factors which suppress industry profitability not ceteris paribus deter entry what might one do with correlated proxy variables should weak results be interpreted the same in a replication test as in a de novo test

sequentially optimal mechanisms this paper establishes that posting a price in each period is a revenue maximizing allocation mechanism in a finite period model without commitment a risk neutral seller has one object to sell and faces a risk neutral buyer whose valuation is private information and drawn from an arbitrary bounded subset of the real line the seller has all the bargaining power she designs a mechanism to sell the object at t but if trade does not occur at t she can propose another mechanism at t 1 we show that posting a price in each period is an optimal mechanism a methodological contribution of the paper is to develop a procedure to characterize optimal dynamic incentive schemes under non commitment that is valid irrespective of the structure of the agent s type 2006 the review of economic studies limited

sequential bargaining with incomplete information this paper describes a simple two person two period bargaining game and solves it using the concept of perfect bayesian equilibrium in which the actions of each player convey information which is used by his opponent the paper examines the effects of changes in bargaining costs the size of the contract zone and the length of the bargaining process on such aspects of the solution as the probability of impasse and the likelihood of concessions the combination of information transfer and the lack of pre commitment embodied in perfectness yields many surprising results common perceptions about the effects of parameter changes on bargaining processes are suspect and should be checked in the particular game being discussed

alcohol and earnings does drinking yield a wage premium this paper examines the relationship between alcohol consumption and earnings for prime age males wage differentials for non moderate and heavy drinkers are estimated using a polychotomous choice model which accounts for the endogenous relationship be tween drinking and earnings we find that moderate alcohol consumption leads to increased earnings relative to abstention however heavy drinking leads to reduced earnings relative to moderate drinking heavy drinkers possess flatter age earnings profiles and attain lower returns for higher education than non and moderate drinkers these results are in contrast to previous research on substance abuse which finds no earnings drop off for heavy users

prices capacity and the entry decision a conditional logit analysis an understanding of what potential entrants consider in reaching an entry decision is important in assessing the validity of some rather fundamental hypotheses concerning the behavior of firms faced with an entry threat the reason is that such hypotheses are based on implicit assumptions concerning what influences the decisions of potential entrants if for example established firms deter entry by adjusting their prices as suggested by the limit pricing hypothesis then it must be true that prices in fact influence potential entrants 1 similarly if firms build capacity to deter entry as suggested recently by spence 8 then it must be true that observed capacity in fact influences the entry decision hence an examination of whether these considerations are important to potential entrants can be interpreted as a test of a necessary though not sufficient condition for the existence of these types of behavior on the part of established firms despite the significance of this question as a foundation upon which a number of important hypotheses concerning firm behavior rest few studies have attempted to estimate the relationship between the relevant market characteristics and the behavior of identifiable potential entrants the reasons for this are not hard to isolate price data of the type required is not generally available for most industries leaving untested the frequently debated relationship between pre entry market price and the entry decision also in the interindustry context in which empirical resesarch is usually conducted it is virtually impossible to account systematically for the differing levels of knowledge and experience among potential entrants and such differences may significantly influence the relative attractiveness of markets for entry thus any attempt to estimate the relationship between market characteristics and the entry decisions of individual potential entrants in the interindustry context will founder on the inability to account for the influence of knowledge and experience on the attractiveness of the potential entrant s choices this paper circumvents these problems by examining the relationship between market

endogeneity in the concentration price relationship causes consequences and curses the ordinary least squares estimator of the effect of concentration on price is biased for two reasons first performance feeds back into structure causing a simultaneous equations bias second as a function of outputs or revenues measured concentration is correlated with determinants of price that are at best measured with error so measured concentration is correlated with the error term with panel data fixed effects procedures can be combined with instrumental variables to eliminate bias from both sources in concentration price regressions for the airline industry the bias can be substantial and negative copyright 1993 by blackwell publishing ltd

alcohol use human capital and wages this article develops and estimates a model of wage determination that isolates the effects of alcohol use on wages as mediated through human capital accumulation although generally insignificant estimation results suggest that moderate alcohol use while in school or working has a positive effect on the returns to education or experience and therefore on human capital accumulation but heavier drinking reduces this gain slightly based on these results alcohol use does not appear to adversely affect returns to education or work experience and therefore has no negative effect on the efficiency of education or experience in forming human capital