strategic interactions and airline network morphology under demand uncertainty abstract in this paper we examine how strategic interactions affect airline network under demand uncertainty we develop a three stage duopoly game at stage 1 airlines determine their network structure linear versus hub and spoke at stage 2 they decide on their capacities at stage 3 firms compete in quantities the main feature of the model is that firms have to decide on network structure and capacities while facing demand uncertainty we show that while hubbing is efficient airlines may choose a linear network for strategic reasons furthermore we show that this structure softens competition by preventing contagion of competition across markets

airport presence as product differentiation there is now widespread recognition that an airline s operation at a given airport greatly affects its competitive position on routes flown out of that airport see m levine 1987 s borenstein 1989 s morrison and c winston 1989 and myself 1989 among many others airlines typically defend any competitive advantage as stemming from the lower costs and better service that are said to be generated by hub and spoke route systems airline critics typically respond that airlines gain market power by dominating individual airports both views are at least plausible huband spoke transportation networks reduce the number of round trips necessary to carry a given number of passengers on a given set of itineraries while increasing the number of passenger miles flown if there are sufficient economies of scale in plane size then the advantages of hubbing can overcome the disadvantage in passenger miles resulting in lower total costs by pooling passengers with different ultimate destinations a hubbed system can also offer more frequent flights than would be economically feasible under a nonstop system it also appears however that airlines gain other advantages from a large presence at an airport incumbent airlines are the major source of financing for many airports and therefore gain a large degree of bureaucratic control over airport operations this control may enable them to block the entry or expansion of rivals airlines with a large presence in a given city also gain advantages from frequent flyer plans and nonlinear travel agent commission schedules see again levine and others if the bureaucratic and marketing advantages of airport presence are sufficient to prevent most attempts at entry then incumbents may gain the ability to exercise traditional market power by restricting output and driving up prices this paper argues that both simple costreducing and naive market power stories are inappropriate for the airline industry i present a model in which consumers are willing to pay a premium for the services of the dominant airline this premium may be related to a number of factors including flight frequency frequent flier miles and travel agent commission overrides this model has the advantage of treating oligopoly product differentiation in an explicit way of treating price as an endogenous variable and of allowing for airport presence to affect both costs and demand

job exit behavior of older men a dynamic programming model of job exit behavior and retirement is constructed and estimated using the method of simulated moments the model and estimation method allow for both unobserved individual effects and unobserved job specific match effects the model is estimated using two different assumptions about individual discount factors first a static model with the discount factor equal to zero is estimated then a dynamic model with the discount factor equal to 95 is estimated in both models it is found that bad health age and lack of education increase the probability of retirement the dynamic model performs better than the static model and has different implications for retirement behavior the job specific effects are an important source of unobserved heterogeneity copyright 1991 by the econometric society

the economics of international codesharing an analysis of airline alliances abstract international airline alliances allow airlines to coordinate their operations in providing international service this paper analyzes the effect of such alliances on traffic levels fares and welfare in the model the benefits of alliances arise because cooperative pricing of trips by the partners puts downward pressure on fares in the interline city pair markets these are markets where travel on both carriers is necessary the loss of competition in the interhub market which connects the hub cites of the partners generates a countervailing effect tending to raise the fare in that market while the presence of economies of traffic density complicates these impacts by generating cost links across markets simulation analysis shows that the above tendencies typically prevail welfare analysis shows that both consumer and total surplus typically rise following formation of an alliance despite the harm to interhub passengers suggesting that the positive effects of alliances may outweigh any negative impacts

the economics of hubs the case of monopoly in this paper we study the optimization problem of an unregulated air carrier which is given the exclusive right to satisfy demand for air travel between any pair of cities it chooses a network of connections and a set of prices to maximize profits thus both network design and prices are endogenous we characterize the solution to this optimization problem when demands and costs are symmetric our main result is that if there are economies of density in the number of individuals travelling between two directly connected cities the optimal network is either a hub of size n 1 or one in which every pair of cities is connected directly

labor force dynamics of older married couples this article analyzes the dynamics of joint labor force behavior of older couples in the united states using the retirement history survey rhs i analyze the determinants of joint retirement and the effect of one spouse s labor force status on the labor force transitions of the other spouse the results reveal strong associations between the labor force transition probabilities of one spouse and the labor force status of the other spouse these result from structural differences in exit and entry behavior by the spouse s status several lagged endogenous variables have substantial effects on behavior even after controlling for unobserved heterogeneity

bargaining in a network of buyers and sellers abstract we analyze bargaining between buyers and sellers who are connected by an exogenously given network players can make repeated alternating public offers that may be accepted by any of the responders linked to each specific proposer our purpose is to find the conditions of the network which drive the price distribution in equilibrium this paper uses graph theory tools to provide necessary and sufficient conditions regarding the architecture of networks for the subgame perfect equilibrium of the bargaining game to coincide with the walrasian outcome

the evolution of u s airline competition studies by academic economists were a significant force in the movement towards deregulation of the domestic airline industry in the early 1970s levine 1965 jordan 1970 keeler 1972 douglas and miller 1974 during the critical 1977 78 period in which deregulation was imposed first de facto by the civil aeronautics board cab and then de jure by congress the chairman and vice chairman of the cab were economists for the 14 years since deregulation economists have continued intensive study of the industry in part because of the unusual availability of reliable firm and transaction level data and in part because of the rare opportunity to observe an industry as it evolves from strict economic regulation to fairly unimpeded competition and strategic behavior the simplest prediction of economists about airline deregulation and one of the few on which nearly all economists agreed was that deregulation would improve consumer welfare in comparison to continued price and entry regulation fourteen years later nearly all economists still agree on this though the degree of enthusiasm for the deregulation outcome varies considerably there was substantial disagreement among economists about the market structure that would result because studies of scale economies in the airline industry had concluded that none existed beyond the scale of the smaller major airlines of the 1970s caves 1962 eads et al 1969 many economists argued that deregulation would result in more than the 11 major airlines that existed at the time of deregulation others predicted that only a few or possibly only one airline would survive at a large scale two noted university of chicago economists sam peltzman and lester telser made a bet in 1979 on whether

equilibria in networks we study a model in which two carriers choose networks to connect cities and compete for customers we show that if carriers compete aggressively e g bertrand like behavior one carrier operating a single hub spoke network is an equilibrium outcome competing hub spoke networks are not an equilibrium outcome although duopoly equilibria in nonhub networks can exist if carriers do not compete aggressively an equilibrium with competing hub spoke networks exists as long as the number of cities is not too small we provide conditions under which all equilibria consist of hub spoke networks

airline network rivalry in this paper the effects of the strategic interaction between deregulated airlines on their network choice are analyzed the authors examine whether switching from a linear to a hub spoke network confers a strategic advantage because it saves costs and improves service quality they find that if hubbing lowers total cost which includes both airline and passenger inconvenience costs the pursuit of strategic advantages usually intensifies the extent of hubbing even if hubbing raises total cost it might be pursued by the airline either because hubbing is a dominant strategy in an oligopolistic setting or because hubbing will be useful in deterring entry

structural models of family labor supply a discrete choice approach a static neoclassical structural model is presented explaining labor supply of both spouses in two adult households in the netherlands family preferences are described with a direct translog utility function with the husbands leisure the wifes leisure and family income as its arguments we assume that the choice set of each family is finite account is taken of the dutch tax and benefits system we allow for hours restrictions and random preferences and account for unobserved wages of nonworkers the models are estimated using smooth simulated maximum likelihood results based upon dutch cross section data from 1987 are illustrated by confidence intervals for elasticities and by several policy simulations excerpt

management control systems for j i t an empirical comparison of japan and the u s just in time manufacturing j i t an essential component of the japanese manufacturing model is increasingly emulated by western corporations while j i t has received considerable conceptual and empirical attention suitable management control systems which are essential to successful implementation have been sorely neglected this study provides large scale empirical evidence comparing management control systems as they relate to j i t in the u s and japan

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

a note on pricing of hub and spoke networks abstract the difference between competitive and monopolistic pricing of airlines hub and spoke networks is examined it is found that under reasonable cost conditions pass through passengers pay lower prices per mile than those originating or ending at the hub thus higher per mile prices in large hubs do not necessarily signal market power

labor force dynamics of older men this paper describes and analyzes movements of older men among labor force states in the united states using quarterly observations derived from the retirement history survey rhs the results indicate substantial undercounts in the biannual data indicating that the prevalence of labor force movements at older ages has been underestimated previously the results show that labor force dynamics at older ages are important including duration and spell occurrence dependence and work experience effects these effects are robust to nonparametric controls for unobserved heterogeneity the estimates indicate that social security benefits have strong effects on the timing of labor force transitions at older ages but that changes in social security benefit levels over time have not contributed much to the trend toward earlier labor force exit excerpt

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

a strategic model of social and economic networks we study the stability and efficiency of social and economic networks when self interested individuals can form or sever links first for two stylized models we characterize the stable and efficient networks there does not always exist a stable network that is efficient next we show that this tension persists generally to assure that there exists a stable network that is efficient one is forced to allocate resources to nodes that are not responsible for any of the production we characterize one such allocation rule the equal split rule and another rule that arises naturally from bargaining of the players

hubs and high fares dominance and market power in the u s airline industry this article estimates the importance of route and airport dominance in determining the degree of market power exercised by an airline the results indicate that an airline s share of passengers on a route and at the endpoint airports significantly influences its ability to mark up price above cost the high markups of a dominant airline however do not create much of an umbrella effect from which carriers with smaller operations in the same markets can benefit the article suggests a number of possible explanations for this asymmetry

experimental games on networks underpinnings of behavior and equilibrium selection in this paper we describe a series of laboratory experiments that implement specific examples of a general network structure specifically actions are either strategic substitutes or strategic complements and participants have either complete or incomplete information about the structure of a random network since economic environments typically have a considerable degree of complementarity or substitutability this framework applies to a wide variety of settings we examine behavior and equilibrium selection the degree of equilibrium play is striking in particular with incomplete information behavior closely resembles the theoretical equilibrium whenever this is unique when there are multiple equilibria general features of networks such as connectivity clustering and the degree of the players help to predict informed behavior in the lab people appear to be strongly attracted to maximizing aggregate payoffs social efficiency but there are forces that moderate this attraction 1 people seem content with in the aggregate capturing only the lion s share of the efficient profits in exchange for reduced exposure to loss and 2 uncertainty about the network structure makes it considerably more difficult to coordinate on a demanding but efficient equilibrium that is typically implemented with complete information

capacity and product market competition measuring market power in a puppy dog industry abstract in this paper we specify and estimate a structural model which accounts for competition in two variables capacity and prices the model has a two stage setup in the first stage firms make capacity decisions followed by a product differentiated price setting game in the second stage since costs are endogenized through the first stage this has important implications for the measurement of market power in the product market in particular simpler one stage specifications would result in a bias in the measurement of market power which can be linked to the taxonomy for two stage games given in fudenberg and tirole 1984 fudenberg d tirole j 1984 the fat cat effect the puppy dog ploy and the lean and hungry look american economic review paper and proceedings 74 361 366 we then estimate this model demand cost short and long run and conduct for the european airline industry using data for the period of 1976 1990 we perform a number of specification tests and reject a simple one stage specification in favor of our two stage set up in particular we find that some degree of market power in the product market exists however market conduct in the two stage set up is significantly less collusive than in the more widely employed one stage specification which is consistent with the direction of bias in puppy dog games this illustrates that collusiveness of firms market conduct in the product market is significantly overestimated whenever capacity competition is not accounted for

network effects congestion externalities and air traffic delays or why not all delays are evil we examine two factors that explain air traffic congestion network benefits due to hubbing and congestion externalities while both factors impact congestion we find that the hubbing effect dominates empirically hub carriers incur most of the additional travel time from hubbing primarily because they cluster their flights in short time spans to provide passengers as many potential connections as possible with a minimum of waiting time non hub flights at the same hub airports operate with minimal additional travel time these results suggest that an optimal congestion tax might have a relatively small impact on flight patterns at hub airports jel l2 l5 l9 d6

communication and coordination in social networks i model people in a coordination game who use a communication network to tell each other their willingness to participate the minimal sufficient networks for coordination can be interpreted as placing people into a hierarchy of social roles or stages initial adopters then followers and so on down to late adopters a communication network helps coordination in exactly two ways by informing each stage about earlier stages and by creating common knowledge within each stage we then consider two examples first we show that low dimensional networks can be better for coordination even though they have far fewer links than high dimensional networks second we show that wide dispersion of insurgents people predisposed toward participation can be good for coordination but too much dispersion can be bad although collective action depends on both social structure and individual incentives these integral aspects have been formalized separately in the fields of social network theory and game theory by considering them together this paper engages the classic question of which structures are conducive to coordination and shows that structure and strategy are related in a mutually interesting way here we consider a coordination game in which each person wants to participate only if others participate social structure is thought of as a communication network by which people tell each other their willingness to participate each person knows whether her neighbours in the network are willing but does not know about anyone else our model is thus a game of incomplete information in which each person given his local knowledge decides whether to participate the main result is a characterization of the minimal sufficient networks for coordination in terms of a hierarchy of social roles or stages initial adopters then followers and so on down to late adopters for example a communication network helps coordination in exactly two ways by informing each stage about earlier stages and by creating common knowledge within each stage we also consider two simple examples first we show that low dimension or strong link networks can be better for coordination even though they have far fewer links than high dimension or weak link networks second we show that wide dispersion of insurgents people predisposed toward participation can be good for coordination but too much dispersion can be bad this paper is built on the assumption that the most basic and common mechanism for coordination is the i ll go if you go mechanism individuals first communicate with each other about their preferences and then each individual chooses whether to participate or not hence a person s participation depends on what he knows about his neighbours it does not depend solely on their participation itself either through learning adaptation or social influence the physical analogies of contagion or diffusion are not

formation of hub cities transportation cost advantage and population agglomeration abstract many cities are located on rivers or coasts such cities developed as transportation hubs or markets for interregional trade since these locations provide better access to other regions local products are collected at such hubs and interregional trade then takes place among these transportation hubs as the volume of trade between hubs increases more workers are needed in order to meet labor demand for shipping and handling commodities resulting in population agglomeration at such hubs formalizing the mechanism described above this paper constructs a simple three location general equilibrium model in which transportation hubs and population agglomeration emerge endogenously

income and outcomes a structural model of intrahousehold allocation there is evidence from several sources that one cannot treat many person households as a single decision maker if this is the case then factors such as the relative incomes of the household members may affect the final allocation decisions made by the household we develop a method of identifying how incomes affect outcomes given conventional family expenditure data the basic assumption we make is that household decision processes lead to efficient outcomes we apply our method to a sample of canadian couples with no children we find that the final allocations of expenditures on each partner depend significantly on their relative incomes and ages and on the level of lifetime wealth

how social security and medicare affect retirement behavior in a world of incomplete markets this paper provides an empirical analysis of how the u s social security and medicare insurance system affect the labor supply of older males in the presence of incomplete markets for loans annuities and health insurance we estimate a detailed dynamic programming dp model of the joint labor supply and social security acceptance decision focusing on a sample of males in the low to middle income brackets whose only pension is social security the dp model delivers a rich set of predictions about the dynamics of retirement behavior and comparisons of actual vs predicted behavior show that the dp model is able to account for wide variety of phenomena observed in the data including the pronounced peaks in the distribution of retirement ages at 62 and 65 the ages of early and normal eligibility for social security benefits respectively we identify a significant fraction of health insurance constrained individuals who have no form of retiree health insurance other than medicare and who can only obtain fairly priced private health insurance via their employer s group health plan the combination of significant individual risk aversion and a long tailed pareto distribution of health care expenditures implies that there is a significant security value for these individuals to remain employed until they are eligible for medicare coverage at age 65 overall our model suggests that a number of heretofore puzzling aspects of retirement behavior can be viewed as artifacts of particular details of the social security rules whose incentive effects are especially strong for lower income individuals and those who do not have access to fairly priced loans annuities and health insurance