computing welfare losses from data under imperfect competition with heterogeneous goods abstract we study the percentage of welfare losses pwl yielded by imperfect competition under product differentiation when demand is linear even if prices outputs costs and the number of firms can be observed pwl is arbitrary in both cournot and bertrand equilibria if in addition the elasticity of demand resp cross elasticity of demand is known we can calculate pwl in a cournot resp bertrand equilibrium when demand is isoelastic and there are many firms pwl can be computed from prices outputs costs and the number of firms we find that price marginal cost margins and demand elasticities may influence pwl in a counterintuitive way we also provide conditions under which pwl increases or decreases with concentration

structural workshop paper discrete choice models of consumer demand in marketing marketing researchers have used models of consumer demand to forecast future sales to describe and test theories of behavior and to measure the response to marketing interventions the basic framework typically starts from microfoundations of expected utility theory to obtain an econometric system that describes consumers choices over available options and to thus characterize product demand the basic framework has been augmented significantly to account for quantity choices to accommodate purchases of several products on a single purchase occasion multiple discreteness and multicategory purchases and to allow for asymmetric switching between brands across different price tiers these extensions have enabled researchers to bring the analysis to bear on several related marketing phenomena of interest this paper has three main objectives the first objective is to articulate the main goals of demand analysis forecasting measurement and testing and to highlight several considerations associated with these goals our second objective is to describe the main building blocks of individual level demand models we discuss approaches built on direct and indirect utility specifications of demand systems and we review extensions that have appeared in the marketing literature the third objective is to explore a few emerging directions in demand analysis including considering demand side dynamics combining purchase data with primary information and using semiparametric and nonparametric approaches we hope researchers new to this literature will take away a broader perspective on these models and see the potential for new directions in future research

cournot and bertrand equilibria compared substitutability complementarity and concavity abstract this paper assesses the view that bertrand equilibrium is intrinsically more competitive than cournot equilibrium we consider an oligopoly model with linear demand and a mixture of substitute and complementary products our results provide support for the conventional wisdom and also indicate its limitations we provide counter examples showing that no clear cut comparison of prices and quantities is possible without strategic complementarity in either of the two games however price competition is indeed more competitive according to the following criteria lower mark up output ratios larger average output and lower average price

a factor analytic probit model for representing the market structure in panel data internal market structure analysis infers both brand attributes and consumer preferences for those attributes from preference or choice data the authors exploit a new method for estimating probit models from panel data to infer market structures that can be displayed in few dimensions even though the model can represent every possible vector of purchase probabilities

welfare reductions from small cost reductions in differentiated oligopoly abstract this paper compares the welfare effects of cost reductions in differentiated bertrand and cournot oligopolies using a linear demand system the paper provides the critical levels of output shares below which a small cost reduction by a bertrand or cournot firm reduces welfare it then shows that the critical value is larger under bertrand competition than cournot competition

endogeneity in brand choice models applications of random utility models to scanner data have been widely presented in marketing for the last 20 years one particular problem with these applications is that they have ignored possible correlations between the independent variables in the deterministic component of utility price promotion etc and the stochastic component or error term in fact marketing mix variables such as price not only affect brand purchasing probabilities but are themselves endogenously set by marketing managers this work tests whether these endogeneity problems are important enough to warrant consideration when estimating random utility models with scanner panel data our results show that not accounting for endogeneity may result in a substantial bias in the parameter estimates

effects of brand preference product attributes and marketing mix variables in technology product markets we develop a demand model for technology products that captures the effect of changes in the portfolio of models offered by a brand as well as the influence of the dynamics in its intrinsic preference on that brand s performance to account for the potential correlation in the preferences of models offered by a particular brand we use a nested logit model with the brand e g sony at the upper level and its various models e g mavica fd dsc etc at the lower level of the nest relative model preferences are captured via their attributes and prices we allow for heterogeneity across consumers in their preferences for these attributes and in their price sensitivities in addition to heterogeneity in consumers intrinsic brand preferences together with the nested logit assumption this allows for a flexible substitution pattern across models at the aggregate level the attractiveness of a brand s product line changes over time with entry and exit of new models and with changes in attribute and price levels to allow for time varying intrinsic brand preferences we use a state space model based on the kalman filter which captures the influence of marketing actions such as brand level advertising on the dynamics of intrinsic brand preferences hence the proposed model accounts for the effects of brand preferences model attributes and marketing mix variables on consumer choice first we carry out a simulation study to ensure that our estimation procedure is able to recover the true parameters generating the data then we estimate our model parameters on data for the u s digital camera market overall we find that the effect of dynamics in the intrinsic brand preference is greater than the corresponding effect of the dynamics in the brand s product line attractiveness assuming plausible profit margins we evaluate the effect of increasing the advertising expenditures for the largest and the smallest brands in this category and find that these brands can increase their profitability by increasing their advertising expenditures we also analyze the impact of modifying a camera model s attributes on its profits such an analysis could potentially be used to evaluate if product development efforts would be profitable

efficiency and surplus bounds in cournot competition we derive bounds on the ratios of deadweight loss and consumer surplus to producer surplus under cournot competition to do so we introduce a parameterization of the degree of curvature of market demand using the parallel concepts of concavity and convexity the more concave is demand the larger the share of producer surplus in overall surplus the smaller is consumer surplus relative to producer surplus and the lower the ratio of deadweight loss to producer surplus deadweight loss over total potential surplus is at rst increasing with demand concavity then eventually

optimizing retail assortments retailers face the problem of finding the assortment that maximizes category profit this is a challenging task because the number of potential assortments is very large when there are many stock keeping units skus to choose from moreover sku sales can be cannibalized by other skus in the assortment and the more similar skus are the more this happens this paper develops an implementable and scalable assortment optimization method that allows for theory based substitution patterns and optimizes real life large scale assortments at the store level we achieve this by adopting an attribute based approach to capture preferences substitution patterns and cross marketing mix effects to solve the optimization problem we propose new very large neighborhood search heuristics we apply our methodology to store level scanner data on liquid laundry detergent the optimal assortments are expected to enhance retailer profit considerably 37 3 and this profit increases even more to 43 7 when sku prices are optimized simultaneously

unequal treatment of identical agents in cournot equilibrium oligopoly models where prior actions by firms affect subsequent marginal costs have been useful in illuminating policy debates in areas such as antitrust regulation environmental protection and international competition we discuss properties of such models when a cournot equilibrium occurs at the second stage aggregate production costs strictly decline with no change in gross revenue or gross consumer surplus if the prior actions strictly increase the variance of marginal costs without changing the marginal cost sum therefore unless the cost of inducing second stage asymmetry more than offsets this reduction in production costs the private and social optima are asymmetric

dynamic natural monopoly regulation time inconsistency moral hazard and political environments this paper quantitatively assesses time inconsistency moral hazard and political ideology in monopoly regulation of electricity distribution we specify and estimate a dynamic model of utility regulation featuring investment and moral hazard we find that 1 there is under investment in electricity distribution capital aiming to reduce power outages 2 more conservative political environments have higher regulated returns and 3 more electricity is lost in distribution in more conservative political environments we quantify the value of regulatory commitment in inducing more investment conservative regulators mitigate welfare losses due to time inconsistency but worsen losses from moral hazard

cournot oligopoly and the theory of supermodular games abstract we reconsider the cournot oligopoly problem in light of the theory of supermodular games invoking the recent ordinal version of this theory proposed by milgrom and shannon we generalize novshek s existence result derive the associated uniqueness result give an extension of a classical existence result under symmetry and provide conditions making a cournot oligopoly into a log supermodular game with the natural order on the action sets we also provide extensive and precise insight as to why decreasing best responses are widely regarded as being typical for the cournot model with production costs several illustrative examples are provided journal of economic literatureclassification numbers c72 l10 l13

modeling asymmetric competition the effects of the marketing actions of one brand can be distributed among its competitors market shares in a complex manner this paper presents and illustrates methods for modeling brand competition and brand strategies in markets where competitive effects can be differentially and asymmetrically distributed we discuss the empirical specification parameter estimation and competitive strategy implications of the models proposed price and advertising competition among eleven brands of an australian household product is used to illustrate the application of these procedures

is 75 of the sales promotion bump due to brand switching no only 33 is abstract several researchers have decomposed sales promotion elasticities based on household scanner panel data a key result is that the majority of the sales promotion elasticity approximately 74 on average is attributed to secondary demand effects brand switching and the remainder is attributed to primary demand effects timing acceleration and quantity increases the authors demonstrate that this result does not imply that if a brand gains 100 units in sales during a promotion the other brands in the category lose 74 units the authors offer a complementary decomposition measure based on unit sales the measure shows the ratio of the current cross brand unit sales loss to the current own brand unit sales gain during promotion the authors report empirical results for this measure they also derive analytical expressions that transform the elasticity decomposition into a decomposition of unit sales effects these expressions show the nature of the difference between the two decompositions to ga

on the microeconomic foundations of linear demand for differentiated products abstract this paper provides a thorough exploration of the microeconomic foundations for the multi variate linear demand function for differentiated products which is widely used in industrial organization the setting is the standard representative consumer with a quasi linear utility function a key finding is that strict concavity of the quadratic utility function is critical for the demand system to be well defined otherwise the true demand function may be quite complex multi valued non linear and income dependent we uncover failures of duality relationships between substitute products and complementary products as well as the incompatibility between high levels of complementarity and concavity the two good case emerges as a special case with strong but non robust properties a key implication is that all conclusions derived in applied economic models via the use of linear demand that does not satisfy the law of demand ought to be regarded with some suspicion

a note on price and quantity competition in differentiated oligopolies abstract in this note we show that the results developed in n singh and x vives 1984 rand j econ 15 546 554 are sensitive to the duopoly assumption if there are more than two firms prices may be higher under price competition than under quantity competition this will be the case if quality differences are large and goods are complements if goods are substitutes high quality firms may earn higher profits under price competition than under quantity competition hence it is not evident which kind of competition is more efficient journal of economic literature classification numbers d43 l13

choice map inferring a product market map from panel data this paper describes choice map a model that infers a product market map from panel data choice map is a stochastic brand choice model a random utility quantal choice model and a multidimensional scaling procedure choice map combines the parsimony of stochastic choice models the rationale of random utility models and the ability of multidimensional scaling procedures to simultaneously infer both brand positions and consumer preferences from preference choice data choice map assumes that consumers have stationary purchase probabilities for the observational period which makes the model best suited to frequently bought mature product categories neither experimental nor survey data are required traditional mapping methods that scale such data may not yield the same structure for low involvement products as will a procedure like choice map that scales behavioral data choice map s descriptive and predictive validity exceeds that of an alternative stochastic brand choice model the dirichlet multinomial for a test data set

certification of corporate social responsibility activities in oligopolistic markets we investigate the impact of alternative certifying institutions on firms incentives to engage in costly corporate social responsibility csr activities as well as their relative market and societal implications we find that the csr certification standard is the lowest under for profit private certifiers and the highest under a non governmental organization ngo with the standard of a welfare maximizing public certifier lying in between yet regarding industry output this ranking is reversed certification of csr activities is welfare enhancing for consumers and firms and should be encouraged finally the market and societal outcomes o f csr certification depend crucially on whether certification takes place before or after firms csr activities

welfare losses under cournot competition abstract in a market for a homogeneous good where firms are identical compete in quantities and produce with constant returns the percentage of welfare losses pwl is small with as few as five competitors for a class of demand functions which includes linear and isoelastic cases we study markets with positive fixed costs and asymmetric firms we provide exact formulae of pwl and robust constructions of markets were pwl is close to one in these two cases we show that the market structure that maximizes pwl is either monopoly or dominant firm depending on demand finally we prove that pwl is minimized when all firms are identical a clear indication that the assumption of identical firms biases the estimation of pwl downwards

combining micro and macro data in microeconometric models or panel samples to improve accuracy of estimation in this paper we show how to do this efficiently we show that the gains from use of marginal information can be substantial we also discuss how to test the compatibility of sample and marginal information

market roll out and retailer adoption for new brands this paper proposes a descriptive model of the spatial and temporal evolution of retail distribution for new packaged goods the distribution model postulates separate processes for local market entry by manufacturers and adoption by retailers given entry of special interest is whether retail adoption occurs along a competitive network with retailers as nodes and overlapping trade areas of these retailers as links the model is calibrated on data covering the introduction of two very successful new brands in the frozen pizza category for these brands manufacturers sequentially enter markets based on spatial proximity to markets already entered spatial evolution and on whether chains in these markets adopted previously elsewhere market selection a retail chain adopts new brands based on the adoption timing of competing chains within its trade territory competitive contagion and on the fraction of its trade area in which the new brand is available trade area coverage the effects of market selection and of trade area coverage create dependencies between market entry and retail adoption because of these dependencies the attraction of a particular market as a lead market depends on its location in the geographic structure of the u s retail trade

measuring market power in the ready to eat cereal industry the ready to eat cereal industry is characterized by high concentration high price cost margins large advertising to sales ratios and numerous introductions of new products previous researchers have concluded that the ready to eat cereal industry is a classic example of an industry with nearly collusive pricing behavior and intense nonprice competition this paper empirically examines this conclusion in particular i estimate price cost margins but more importantly i am able empirically to separate these margins into three sources i that which is due to product differentiation ii that which is due to multi product firm pricing and iii that due to potential price collusion the results suggest that given the demand for different brands of cereal the first two effects explain most of the observed price cost margins i conclude that prices in the industry are consistent with noncollusive pricing behavior despite the high price cost margins leading firms are able to maintain a portfolio of differentiated products and influence the perceived product quality it is these two factors that lead to high price cost margins

price induced patterns of competition this research focuses on how price changes influence the observed pattern of brand competition the paper begins with a basic utility model formulation and examines the implications of three major classes of preference distributions on the expected patterns of competition a price tier model is proposed to operationalize the theory and to allow predictive testing the price tier model is estimated on 28 brands across four product categories the results show a specific asymmetric pattern of price competition higher price higher quality brands steal share from other brands in the same price quality tier as well as from brands in the tier below however lower price lower quality brands take sales from their own tier and the tier below brands but do not steal significant share from the tiers above the results are consistent with a bimodal preference distribution with the regular price indifference point being located toward the lower quality end of the preference distribution for the categories analyzed

estimating demand heterogeneity using aggregated data an application to the frozen pizza category this paper combines different aggregate level data sets to identify new product demand in consumer packaged goods cpg categories our approach augments market level time series data with widely available summaries of household purchase behavior i e brand penetration and purchase set size data we show that this augmentation is helpful in the estimation of consumer heterogeneity for instance observing a brand with relatively large shares and low penetration typically indicates that preferences are dispersed with relatively few customers liking the brand a lot whereas the combination of share and penetration is informative about heterogeneity with realistic sample sizes in isolation neither variable may lead to precise estimates of heterogeneity in addition other widely available data e g category penetration is helpful in estimating the size of the total market using a large monte carlo study the paper demonstrates the benefits of the proposed approach in estimating model parameters price elasticities and brand switching empirically the approach is used to evaluate the launch of a new national brand digiorno in the frozen pizza category the new brand is inferred to be very successful at expanding the category while avoiding cannibalization of existing company share using only standard information i e market shares to estimate the demand model leads in our data to poor estimates of the degree of consumer taste variation and of switching to a new brand

new products the antidote to private label growth abstract as private labels pls continue to grow in power and market share product innovation has become one of the strongest weapons in the national brand nb manufacturer s arsenal in this article the author assesses when and to what extent new products change nbs market position to address this question more than 300 nb and pl introductions are analyzed using a multibreak model that quantifies the impact of product introductions on own share rival nb and pl share and category sales drawing on empirical generalizations the author finds that products introduced by leading nbs standard pls and premium pls are more likely to increase category sales than products introduced by follower nbs or economy pls new products introduced by leader and follower nbs more often boost own share thus new products help prevent the decline of nb shares with respect to competitive impact new products affect rival shares with the exception of those launched by economy pls still nbs tend to hurt rival nbs

technical note a comparison of bertrand and cournot profits in oligopolies with differentiated products we compare equilibrium profits of bertrand price and cournot quantity competition in oligopolies with an arbitrary number of nonsymmetric firms offering differentiated substitutable products under an affine demand function we provide a precise characterization of the profit relationship in terms of 1 the number of firms 2 their relative quality and cost differences and 3 the competition intensity defined as the maxiumum absolute value of total change in competitors demand over change in own demand due to a unit change in own price we first examine the case where firms have the same demand sensitivity to own price and the same demand sensitivity to competitor prices but different cost and quality parameters for this case we prove that the total profit of the industry under cournot competition is at least as high as the total profit under bertrand competition if the number of firms is less than 28 or if the competition intensity is less than 0 909 or if the differences in quality and cost competitiveness between firms are small we also prove that for each firm the profit achieved under cournot competition is at least as high as the profit achieved under bertrand competition if the number of firms is less than eight or if the competition intensity is less than 0 739 we then provide numerical and analytical results that qualitatively support the same conclusions for general affine demand functions with variable demand sensitivities to prices

comparing bertrand and cournot in mixed markets abstract we revisit the classic comparison between bertrand and cournot outcomes in a mixed market with private and public firms the results are often strikingly different and opposite to the ones obtained from a similar comparison in the standard setting with all profit maximizing firms

estimating cannibalization rates for pioneering innovations to evaluate the success of a new product managers need to determine how much of its new demand is due to cannibalizing the firm s other products rather than drawing from competition or generating primary demand we introduce a time varying vector error correction model to decompose the base sales of a new product into its constituent sources the model allows managers to estimate cannibalization effects and calculate the new product s net demand which may be considerably less than its total demand we apply our methodology to the introduction of the lexus rx300 using detailed car transaction data this case is especially interesting because the lexus rx300 was the first crossover sport utility vehicle suv implying that its demand could come from both the luxury suv and the luxury sedan categories because lexus was active in both categories there was a double cannibalization potential we show how the contribution of the different demand sources varies over time and discuss the managerial implications for both the focal brand and its competitors

equilibrium prices in the bertrand and cournot oligopolies abstract the equilibrium prices for the bertrand and cournot oligopolies with product differentiation are compared if all firms have linear demand and cost functions and if in addition the jacobian matrix of the demand functions has a dominant negative diagonal the cournot equilibrium prices are not lower than the bertrand ones the general condition for the comparison of the bertrand and cournot equilibrium prices can be derived even if the nonlinearity is involved in the cost and or demand functions

a dynamic analysis of market structure based on panel data internal market structure analysis infers brand positions in an attribute space from preference and choice data given a market in which consumers have heterogeneous tastes for attributes previous market structure models have adopted a static framework e g elrod 1988 chintagunta 1994 elrod and keane 1995 furthermore they assumed that consumer perceptions of brand attributes do not vary across consumers yet these approaches may render inaccurate representations of market structure if there is state dependence in consumer choice behavior this paper attempts to incorporate consumer choice dynamics into market structure models by specifying the source of choice dynamics explicitly in particular the process by which past purchases affect current choices is modeled in a framework which captures both consumer habit persistence and variety seeking behavior more specifically consumer preferences for brand attributes are modeled to depend on the attributes of brands bought on the previous purchase occasion furthermore the modeling approach adopted incorporates heterogeneity in both consumer preferences and perceptions of brand attributes the audience of this paper includes practitioners and academics interested in understanding consumer choice processes and inferring market structure from consumer choice data the proposed models are estimated on nielsen scanner panel data for margarine peanut butter yogurt and liquid detergent using simulated maximum likelihood techniques the empirical results suggest that accounting for choice dynamics improves both in sample and out of sample fit the results indicate that the average consumer is habit persistent in all the product categories studied this result is consistent with the findings of kannan and sanchez 1994 who conducted an aggregate analysis of consumer variety seeking behavior across product categories however the results obtained in this paper suggest that consumers are heterogeneous with respect to the processes by which past purchases affect current purchases these results provide strong evidence for habit persistence and variety seeking in brand attributes to be the behavioral source of consumer choice dynamics in food categories thus consumer tastes utility weights seem to be affected by the attributes of the brands consumed in the past given the empirical result that a large proportion of consumers are habit persistent this suggests that tastes are reinforced by the brand attributes consumed in the past the empirical results also show that not accounting for state dependence in market structure models for panel data may produce misleading results that is depending on consumer behavior patterns models that do not account for state dependence may distort the true nature of competition among brands more specifically the results confirm the expectation that if there is habit persistence that is if consumer tastes are reinforced by attributes of brands consumed in the past models that do not capture this choice dynamics will overestimate the distance between similar brands furthermore the policy experiments conducted suggest that 1 static models overestimate the short run impact of a price cut on the sales of the brand on promotion 2 price cuts hurt the sales of the more similar brands more and 3 free samples affect relatively less similar brands the most finally this paper studies variety seeking and habit persistence across brands over purchase occasions however variety seeking behavior may also involve the purchase of a portfolio of brands or items at a purchase occasion consumers may buy multiple items knowing that prior to the next trip they may want to consume different items simanson 1990 walsh 1995 this type of behavior can be modeled within the context of dynamic expected utility maximization with forward looking consumers the development and estimation of market structure models that include forward looking consumers who maximize expected utility over a planning horizon incorporating their future tastes and needs and shopping for an inventory of brands remain an important future research issue

oversight of long term investment by short lived regulators certain regulators of economic activity like utility regulators and government procurement officers typically serve for relatively short periods of time the authors consider how to best motivate long term investment in the presence of short lived regulators a firm s investment decision is overseen by one regulator whether the investment is ultimately adopted is determined by a second distinct regulator each regulator is concerned with the welfare of its own contemporary population transfer payments between populations are limited and relevant data cannot be verified by third parties underadoption and underinvestment on average result although overinvestment may also occur under the optimal regulatory charter copyright 1991 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

choice set heterogeneity and the role of advertising an analysis with micro and macro data abstract the authors show how to use microlevel survey data from a tracking study on brand awareness in conjunction with data on sales and advertising expenditures to improve the specification estimation and interpretation of aggregate discrete choice models of demand in a departure from the commonly made full information assumption they incorporate limited information in the form of choice sets to reflect that consumers may not be aware of all available brands at purchase time they find that both the estimated brand constants and the price coefficient are biased downward when consumer heterogeneity in choice sets is ignored these biased estimates can lead firms to make costly price setting mistakes in addition the tracking data enable the authors to identify separately two processes by which advertising influences market shares they find that advertising has a direct effect on brand awareness inclusion in choice set in addition to its effect on consumer preferences increase in utility this

on the efficiency of bertrand and cournot equilibria with product differentation in a differentiated products setting with n varieties it is shown under certain regularity conditions that if the demand structure is symmetric and bertrand and cournot equilibria are unique then prices and profits are larger and quantities smaller in cournot than in bertrand competition and as n grows both equilibria converge to the efficient outcome at a rate of at least 1n if bertrand reaction functions slope upwards and are continuous then even with an asymmetric demand structure given any cournot equilibrium price vector one can find a bertrand equilibrium with lower prices in particular if the bertrand equilibrium is unique then it has lower prices than any cournot equilibrium

a simultaneous equations model of coffee brand pricing and advertising this paper explores the relationship between a differentiated brand s market share and its price in the con text of a model that recognizes the endogeneity of the brand s advertising behavior and pricing decisions the empirical analysis suggests that general foods charged higher prices for its regular grind maxwell house coffee in geographic areas where the brand s market share was relatively large available cross sectional time series data and company documents sug gest that this empirical relationship is attributable to the preference grocery retailers have for putting dominant coffee brands on special rather than cross sectional variations in costs market concentration or consumer tastes i introduction r his paper explores the relationship between a differentiated brand s market share and its price in the context of a model that recognizes the endogeneity of the brand s advertising behav ior and pricing decisions by using price as the measure of economic performance rather than accounting profits and by recognizing that adver tising is determined simultaneously with price the empirical tests reported here avoid some of the more serious problems of structure perfor mance studies moreover by focusing on the rela tionship between a single brand s market share and price this study analyzes the unilateral mar ket power of a differentiated brand as well as the effect of market wide concentration on a brand s prices the empirical analysis focuses on the hypothe sis that the general foods corporation charged higher prices for its regular grind maxwell house coffee in geographic areas where the brand s market share was large during the 1970s we identify a statistically significant positive relation ship between maxwell house s wholesale price

anything goes with heterogeneous but not always with homogeneous oligopoly abstract corchon and mas colell 1996 on the stability of best reply and gradient systems with applications to imperfectly competitive models economics letters 51 59 65 showed that in heterogeneous oligopoly almost everything is possible in order to obtain a similar result for homogeneous oligopoly either one needs an externality in the cost function or the reaction correspondences should fulfill a special condition

the multiprincipal nature of government abstract one of the theoretical tools required to open the black box of the government organization is the theory of multiprincipals which describes how different incentive mechanisms compete with each others in viewing the set of relationships between several government bodies and the entities they regulate as a set of competing contracts in which the control of the regulatory process is shared amongst these different regulators we can address the question of the costs and the possible benefits of such structural separation first this paper surveys the previous literature on the topic then it traces out the possible benefits of such structures to the non benevolence of regulators we discuss also how regulatory rights of control and communication channels must be designed all together to deal with this problem

on stackelberg games in a homogeneous product market abstract in a homogeneous product duopoly with concave demand and strictly convex costs we bring together all the standard results of quantity stackelberg games provide some new results with price stackelberg games and compare the equilibrium configuration of the quantity games with the price games in the price stackelberg game we show there is a unique spne where the leader chooses a lower price than the follower but both get equal payoffs we prove that generally quantity stackelberg games are less competitive than price stackelberg games however we also demonstrate the possibility of a reversal of this result

how to compete cournot versus bertrand in a vertical structure with an integrated input supplier we study whether a quantity or a price contract is chosen at equilibrium by one integrated firm and its retail competitor in a differentiated duopoly using a similar vertical structure arya et al 2008 show that bertrand competition is more profitable than cournot competition which contrasts with conventional wisdom in this article we first demonstrate that such a result is robust to the endogenous determination of the type of contract second by introducing managerial incentives in the model we find that delegation to managers may lead each firm to choose a quantity contract and as long as products are sufficiently differentiated entails conflicting choices causing nonexistence of equilibrium in pure strategies significantly high product substitutability reconciles firms objectives under delegation leading unique or multiple equilibria with symmetric types of contracts to arise

carbon tax emission standards and carbon leak under price competition we consider a two country model of price competition with one polluting firm in each country and differentiated products assuming away to simplify abatement efforts and input substitution we compare the impact on output leakages and trade volumes of a carbon tax versus an emission standard policy unilaterally enacted by the home country under the tax the two firms set their prices simultaneously in a bertrand game under the standard the home firm s price is conditioned on the price of the foreign firm so as to abide the emission constraint as a result the tax leads to higher leakages and global emissions than the standard the standard also implies a better trade balance for the home country than the tax

helping minor firms reduces welfare the effect on national welfare of uneven technical progress and eli mination of a firm is analyzed under the existence of a cournot oligopolistic sector an increase in the share of an inefficient firm owing to its innovations results in a shift of production from more efficient firms to the inefficient firm causing a less efficie nt allocation of production it may decrease welfare even though the innovation itself is beneficial conversely policies keeping ineffic ient firms from innovations or eliminating them may increase welfare though they make the market structure more oligopolistic copyright 1988 by royal economic society

rationalizability learning and equilibrium in games with strategic complementarities we study a rich class of noncooperative games that includes models of oligopoly competition macroeconomic coordination failures arms races bank runs technology adoption and diffusion r d competition pretrial bargaining coordination in teams and many others for all these games the sets of pure strategy nash equilibria correlated equilibria and rationalizable strategies have identical bounds also for a class of models of dynamic adaptive choice behavior that encompasses both best response dynamics and bayesian learning the players choices lie eventually within the same bounds these bounds are shown to vary monotonically with certain exogenous parameters we study the class of noncooperative supermodular games introduced by topkis 1979 and further analyzed by vives 1985 1989 who also pointed out the importance of these games in industrial economics supermodular games are games in which each player s strategy set is partially ordered the marginal returns to increasing one s strategy rise with increases in the competitors strategies so that the game exhibits strategic complementarity 2 and if a player s strategies are multidimensional marginal returns to any one com ponent of the player s strategy rise with increases in the other components this class turns out to encompass many of the most important economic applications of noncooperative game theory in macroeconomics diamond s 1982 search model and bryant s 1983 1984 rational expectations models can be represented as supermodular games in each of these models more activity by some members of the economy raises the returns to increased levels of activity by others in oligopoly theory some models of bertrand oligopoly with differentiated products qualify as supermodu lar games in these games when a firm s competitors raise their prices the marginal profitability of the firm s own price increase rises a similar structure is present in games of new technology adoption such as those of dybvig and spatt 1983 farrell and saloner 1986 and katz and shapiro 1986 when more users hook into a communication system or more manufacturers adopt an interface standard the marginal return to others of doing the same often rises similarly in some specifications of the bank runs model introduced by diamond and dybvig 1983 when more depositors withdraw their funds from a bank it is more worthwhile for other depositors to do the same in the warrant exercise

price vs quantity competition in a vertically related market this paper demonstrates that the standard conclusions regarding the comparison of cournot and bertrand competition are reversed in a vertically related market with upstream monopoly and trading via two part tariffs in such a market downstream cournot competition yields higher output lower wholesale prices lower final prices higher consumers surplus and higher total welfare than bertrand competition

the dynamic efficiency of regulatory constitutions in this article we model regulation as a repeated game between a utility facing a random sequence of demands and a regulator tempted to underreward past investment rate of return regulation designed with a constitutional commitment to an adequate rate of return on capital prudently invested is able to support an efficient investment program as a subgame perfect nash equilibrium for a larger set of parameter values than rate of return regulation without such a commitment furthermore rate of return regulation is superior to price regulation according to the same criterion assuming that the regulator is unable to make state contingent transfer payments

endogeneity and heterogeneity in a probit demand model estimation using aggregate data two issues that have become increasingly important while estimating the parameters of aggregate demand functions to study firm behavior are theendogeneity of marketing activities typically price andheterogeneity across consumers in the market under consideration ignoring these issues in the estimation of the demand function parameters can lead to biased and inconsistent estimates for the effects of marketing activities endogeneity and heterogeneity have achieved prominence in large measure because of the increasing popularity of logit models to characterize demand functions usingaggregate data the logit model accounts for purchase incidence and brand choice by including a no purchase alternative in the consumer s choice set this allows for category sales to change as a function of the marketing activities of brands in the category there are three issues with using the logit model with the no purchase option to characterize demand when studying competitive interactions among firms 1 the marketing literature dealing with brand choice behavior at the consumer level has found that the iia restriction is not appropriate as each brand in the choice set is more similar to some brands than it is to others 2 studies have found that the purchase incidence decision is distinct from the brand choice decision hence it may not be appropriate to model the no purchase decision as just another alternative in the choice set with the iia restriction holding across all brands and the no purchase option 3 even if the distinction between the purchase incidence and brand choice decisions is accounted for via for example a nested logit specification accounting for the purchase incidence decision with aggregate data requires assumptions for computing the share of the no purchase alternative which is otherwise unobserved in this paper we propose a probit model as an alternative to the logit model to specify the aggregate demand functions of firms competing in oligopoly markets the probit model avoids the iia property that affects the logit model at the individual consumer level furthermore the probit model can naturally account for the distinction between the purchase incidence and brand choice decisions due to the general covariance structure assumed for the utilities of the alternatives we demonstrate how the parameters of the proposed model can be estimated using aggregate time series data from a product market in the estimation we account for the endogeneity of marketing variables as well as for heterogeneity across consumers our results indicate that both endogeneity as well as heterogeneity need to be accounted for even after allowing for a non iia specification at the individual consumer level specific to our data we also find that ignoring endogeneity has a bigger impact on the estimated price elasticities than ignoring the effects of heterogeneity a comparison of the elasticities obtained from the probit model with those from the corresponding logit specification indicates that therange of elasticities obtained from the probit model across brands is larger than that obtained from the logit the results have implications for issues such as firm level pricing in addition to specifying a probit model and providing comparisons with the logit model the paper also addresses the third issue raised above we propose a simple alternative to the purchase incidence brand choice specification by decomposing the demand for a brand into a category demand equation and a conditional brand choice share equation we provide a comparison of results from this specification to those from the specification that includes the no purchase alternative and find that estimated elasticities are sensitive to the specification used we also estimate the demand function parameters using a traditional specification such as the double logarithmic model here we find that the estimated elasticities could be signed in such a manner as to be not useful for firm level pricing decisions one of the key limitations of the proposed model is that while it accounts for the purchase incidence and brand choice decisions of households it does not account for differences across consumers in their purchase quantities the model and analysis are best suited for product categories in which consumers typically make single unit purchases another limitation is more practical in nature while recent advances have been made in computing probit probabilities it could nevertheless be a challenge to do so when the number of alternatives is large

renegotiation design with multiple regulators abstract one striking feature of the internal organization of governments is the existence of multiple regulators this paper explains this organizational choice as coming from the government s limited ability to commit the separation of powers between two regulators is modeled as a stackelberg common agency game with respect to the case of a single regulator the allocative efficiency and the regulated firm s informational rent are both reduced in the unique equilibrium of this game however when regulators have a limited ability to commit this static cost of regulators separation becomes a dynamic benefit separation makes renegotiation harder and improves commitment journal of economic literature classification numbers d82 l51