resolving differences in willingness to pay and willingness to accept reply gwendolyn c morrison 1997 raises a logical point regarding our experimental test of the divergence between willingness to pay wtp and willingness to accept wta measures of economic value shogren et al 1994 she argues that our design does not provide a true test of the existence of a fundamental endowment effect since we did not control for the potential of a pivoting indifference map daniel kahneman et al 1990 she concludes that even though our ev idence shows that the mean wtp and wta bids for market goods with close substitutes e g candy bars and coffee mugs converge after market experience the endowment effect might still be alive and well albeit at statisti cally insignificant levels

reversing urban bias in african rice markets evidence from senegal summary urban bias constitutes an important institutional impediment to economic development in poor countries some african governments now recognize that they should invest in agricultural productivity in order to reverse urban bias but often forget the equally important objective of investing in quality tailored to consumers so as to reverse urban bias footprint on food markets we conduct framed field experiments in two major urban markets in senegal and find that the majority of urban consumers are willing to pay quality premiums for local rice suggesting that investment in post harvest rice quality is a priority in the reversal of urban bias 2012 elsevier ltd all rights reserved

identification of strategies to improve goat marketing in the lowlands of ethiopia a hedonic price analysis abstractthis article aims at identifying factors that determine market prices of goats and analyse potential mechanisms by which smallholder goat producers could maximize their benefits data on 35

effect of government quality grade labels on consumer demand for pork chops in the short and long run abstract despite ample evidence of pork quality variability at present there are few signals that would incentivize growers to produce higher quality pork using split sample choice experiment data from a nationwide online survey of u s pork chop eaters this research determines changes in pork chop demand in response to a potential change in u s government policy that would introduce a new pork quality grading system based on color scores our simulations include novel short run projections in which the conditional and latent class logit models are inverted to yield inverse demand curves the inverse demand curves are used to calculate equilibrium prices and pork revenue given a fixed supply of different pork qualities we supplement these calculations with a more traditional long run analysis in which prices are fixed and quantities of different qualities adjust compared to the status quo control of no quality grades we find that two grading systems based on alternative nomenclatures select choice prime vs good better best both have the potential to increase pork chop sales and revenue to the pork industry however we also find that if only the highest quality is labeled revenue could fall as the increase in demand for the higher quality is offset by the fall in demand for the lower qualities results also highlight important heterogeneity in consumer preferences and although sensory studies strongly suggest redder pork chops are more highly preferred there remains a non trivial share of consumers who prefer whiter pork even after quality grade labeling overall this study offers several insights that can help inform labeling and quality grading policies

an experimental approach to valuing new differentiated products abstract an experimental store was created to evaluate initial demand for locally produced and guaranteed tender steak products as a more realistic alternative to contingent valuation cv and dichotomous choice experimental methods strengths of the approach are incentive compatibility a realistic consumption set and a familiar choice environment consumers selected among usda choice premium quality lean guaranteed tender and locally produced strip steaks a double hurdle count data model indicated initial willingness to pay wtp for locally produced steak comparable to prior cv results but demand was highly elastic demand for premium quality steak crowded out demand for the guaranteed tender product contrasting with prior dichotomous choice experimental results

a spatial theory of positive and negative campaigning abstract in order to explore the content of electoral campaigns this paper makes two modifications to hotelling s model of spatial competition first we assume that agents inherit initial locations and engage in costly relocation second an agent s relocation is affected by her rival s actions we investigate how a candidate allocates resources between positive campaigning which influences voters perceptions of her own ideology and negative campaigning which influences her opponent s perceived ideology our theory predicts that the candidate who is perceived as having less attractive personal attributes runs a relatively more negative campaign the theory s implications are illustrated for the 1988 presidential election journal of economic literature classification numbers c7 h0

product diversity in asymmetric oligopoly is the quality of consumer goods too low we analyse an oligopoly model incorporating horizontal differentiation and quality differences high quality goods are overpriced and underproduced when the market is fairly well covered low quality products may be profitable when their net social contribution is negative implying excessive entry in a relatively uncovered market even low quality goods are underproduced and there may be underentry when fixed costs are independent of quality the market tends to select the right firms otherwise the market may produce low quality products when it should produce high quality ones the model is calibrated using market data for yoghurt

the benefits and costs of strong patent protection a contribution to the current debate abstract today s conventional wisdom is that strong patent rights are conducive to economic progress yet not long ago students of the patent system took a more nuanced position arguing that often strong patents were not necessary to induce invention and entailed significant economic costs several empirical studies have supported this position however the current advocacy invokes theories of the positive benefits of patents that were repressed in the earlier more negative analyses this essay reviews these theories and the empirical evidence that might bear on them the authors conclude that there is reason for concern that the present movement towards stronger patent protection may hinder rather than stimulate technological and economic progress

effects and value of verifiable information in a controversial market evidence from lab auctions of genetically modified food food products containing genetically modified gm ingredients have entered the market over the past decade the biotech industry and environmental groups have disseminated conflicting private information about gm foods this paper develops a unique methodology for valuing independent third party information in such a setting and applies this method to consumers willingness to pay for food products that might be gm data are collected from real consumers in an auction market setting with randomized information and labeling treatments the average value of third party information per lab participant is small but the public good value across u s consumers is shown to be quite large jel c91 d12 d82

informative advertising and product match abstract this paper studies informative advertising in a variety of market structures for which some consumers are informed about two differentiated products while other consumers are uninformed we characterize a unique symmetric subgame perfect nash equilibrium in advertising and pricing and analyze the welfare properties of the equilibrium remarkably total surplus is non monotonic in advertising in a duopoly market the equilibrium level of advertising may be more or less than socially optimal we also study the effect of a trade association and compare these results with the first best solution and a multiproduct monopolist

informative advertising with differentiated products in this paper we study the role of promotional expenditures by sellers in a model of product differentiation advertising conveys full and accurate information about the characteristics of products heterogeneous consumers who have no source of information other than advertisements seek to purchase the products that best fit their needs despite the roles played by advertising in improving the matching of products and consumers and in increasing the elasticity of demand faced by each firm we find that the market determined levels of advertising are excessive given the extent of diversity in the market we derive a promotional equilibrium based on a specific information transmission technology paying explicit attention to the structure of consumer information and its impact on firms demand curves this allows us to study the effects of changes in the advertising technology including an increased ability to target messages to specific groups of consumers on the equilibrium in the product market we find that decreased advertising costs may reduce profits by increasing the severity of price competition

willingness to pay versus expected consumption value in vickrey auctions for new experience goods over the past two decades vickrey auctions have been widely used to elicit willingness to pay for new food products this article shows that in a multiperiod context it can be optimal for consumers to bid higher than the expected consumption value for a new experience good to obtain information about how the new good fits into their preference set the degree of uncertainty about the consumption value the purchasing frequency and expected future market prices affect both the expected value of the quality information and the subgame perfect bidding strategy in vickrey auctions for new experience goods

buyer confusion and market prices we employ a price setting duopoly experiment to examine whether buyer confusion increases market prices each seller offers a good to buyers who have homogeneous preferences sellers decide on the number of attributes of their good and set prices the number of attributes bears no cost to the sellers and does not affect the value of the good to the buyers but adds complexity to buyers evaluation of the goods the experimental results indicate that the buyers make more suboptimal choices and that prices are higher when the number of attributes of the goods is higher moreover prices and profits are higher than those in a benchmark treatment with perfectly rational robot buyers

consumer preferences for fresh food items with multiple quality attributes evidence from an experimental auction of pork chops this study illustrates an application of experimental auction methods using both experimental economics and experimental design to evaluate consumer perceptions and willingness to pay wtp for fresh pork chops we test and reject hypotheses that a market prices and consumers wtp are unaffected by the level of attributes embodied in the pork chops b appearance based on photographs or actual product and actual taste are equally good sources of consumer information and c consumers are consistent in their preferences for fresh pork attributes a major conclusion is that predicting consumer demand for fresh pork or any fresh food based on appearance without tasting is unproductive

paying positive to go negative advertisers competition and media reports this paper analyzes a two sided market for news where two rival advertisers may pay a media outlet to conceal negative information about the quality of their own product paying positive to avoid negative and or to disclose negative information about the quality of their competitor s product paying positive to go negative we show that competition in the product market does not necessarily prevent the emergence of commercial media bias whether or not competing advertisers end up having negative consequences on news accuracy ultimately depends on the extent of correlation in the quality of their products the lower the correlation the higher the expected accuracy of the media outlet s reports these findings provide a rationale to explain the observed differences in the extent of commercial media bias across seemingly similar industries or products within the same media market the results are robust to the presence of multiple media outlets and to asymmetries between the advertisers overall the paper provides theoretical insights for media regulators and for the empirical literature examining the link between advertising and news contents

information management and pricing in platform markets we study platform markets in which the information about users preferences is dispersed first we show how the dispersion of information introduces idiosyncratic uncertainty about participation decisions and how the latter shapes the elasticity of the demands and the equilibrium prices we then study the effects on profits consumer surplus and welfare of platform design blogs forums conferences advertising campaigns post launch disclosures and other information management policies affecting the agents ability to predict participation decisions on the other side of the market

welfare gains from quality certification of infant foods results from a market experiment in mali in low income countries malnutrition is often most severe among infants of six to twenty four months they need higher density foods than the family diet but density is a credence attribute we hypothesize that the premium now paid for heavily advertised brands reflects demand for quality assurance which could be provided at lower cost to competing firms through third party certification we use a new market experiment to find that mothers average willingness to pay for certification is about 1 75 kg or four times its cost so that total economic surplus gains from introducing certification to mali would be on the order of 1 million annually

true monopolistic competition as a result of imperfect information the paper restates hart s 1985a 1985b definition of large group monopolistic competition distinguishes it from oligopolistic competition and raises the question of whether there are reasonable circumstances that give rise to true monopolistic competition as defined the purpose is to show that consumers imperfect information may create conditions that will turn an otherwise oligopolistic market into a truly monopolistically competitive one

social learning and dynamic pricing of durable goods we analyze the impacts of social learning sl on the dynamic pricing and consumer adoption of durable goods in a two period monopoly consumers can make either early uninformed purchases or late but potentially informed purchases as a result of social learning several results are derived first we identify the market conditions under which ex ante homogeneous consumers may choose to purchase at different times second equilibrium adoption may demonstrate inertia where all adopt late or frenzy where all adopt early in particular adoption inertia appears when sl intensity is reasonably high but may vanish when sl intensity exceeds a certain threshold third firm profits and social welfare first weakly decrease in sl intensity and may then jump up by a lump sum amount at the threshold sl intensity level mentioned above last we show that the firm potentially benefits from informative advertising or investing to cultivate more social learning

advertising as signal jamming abstract this paper considers a model of informative advertising that allows firms to jam the consumers signals on product quality before choosing prices at a second stage we find that the price competition at the second stage may overrule the basic insights from the signal jamming approach in other areas of application as a consequence a firm may advertise more intensely the higher is the difference of the expected product qualities moreover a firm s optimal advertising intensity can decrease with quality uncertainty

experimental auction procedure impact on valuation of quality differentiated goods despite increased use of experimental auctions a myriad of different procedures are being employed without formal consideration of how the procedures might affect results this study investigates the effect of several procedural issues on valuation estimates from experimental auctions results indicate the second price auction generates higher valuations than english becker degroot marschak bdm and random nth price auctions especially in latter bidding rounds and that random nth price auction yields lower valuations than english and bdm auctions we find that endowing subjects with a good prior to eliciting bids can have an impact on valuations but the effect varies across auction mechanism

do native and invasive labels affect consumer willingness to pay for plants evidence from experimental auctions ornamental plant sales have been identified as an important vector for the introduction of invasive plants increased concerns about the economic and ecological costs of invasive plants have spawned interest in identifying strategies to curtail introductions one possible strategy is labeling plants based on whether they are invasive or native the primary purpose of this paper was to explore how labeling plants based on invasive and native attributes might affect consumer demand to accomplish this objective a second price auction was used to elicit the willingness to pay wtp for plants with and without labels on average we found a 0 35 premium for plants labeled as noninvasive and native and a 1 01 to 1 66 discount for plants labeled as invasive the size of these premiums and discounts differed in relation to various demographic attitudinal and preference related factors overall our results suggest that labeling plants as invasive or native could be a viable strategy for reducing the introduction of invasive plants

what is it about organic milk an experimental analysis auction experiments were used to examine demand relationships and willingness to pay wtp for organic rbst free no antibiotics used and conventional milk elasticities showed strong substitute and complement relationships between organic rbst free and no antibiotics varieties the sum of the latter two s premiums were not significantly different than the organic premium suggesting diminishing marginal utility for added attributes results from a two stage heteroskedastic tobit model demonstrated that wtp premiums for the varieties differ significantly by demographics and beliefs regarding the conventional version these suggest market segments for rbst free and no antibiotics versions could succeed alongside organic benefiting consumers and producers copyright 2007 oxford university press

online shopping and platform design with ex ante registration requirements we study platform design in online markets in which buying involves a nonmonetary cost for consumers caused by privacy and security concerns firms decide whether to require registration at their website before consumers learn relevant product information we derive conditions under which a monopoly seller benefits from ex ante registration requirements and demonstrate that the profitability of registration requirements is increased when taking into account the prospect of future purchases or an informational value of consumer registration to the firm moreover we consider the effectiveness of discounts store credit as a means to influence the consumers registration decision finally we confirm the profitability of ex ante registration requirements in the presence of price competition the online appendix is available at https doi org 10 1287 mnsc 2016 2595 this paper was accepted by j miguel villas boas marketing

consumer loss aversion product experimentation and tacit collusion abstract two firms compete to attract loss averse consumers that are uncertain about how well the goods on sale fit their needs to resolve valuation uncertainty firms can allow prospective customers to test experiment their products before purchase we investigate firms dynamic incentives to allow experimentation and analyze the resulting effects on the profitability and the stability of tacit collusion depending on the regulatory regime in place i e whether experimentation is forbidden mandated or simply allowed but not imposed laissez faire the degree of loss aversion has ambiguous effects both on the profits that firms can achieve through tacit collusion and on the stability of these agreements while in static environments consumer welfare is always maximized by a policy that forbids experimentation the opposite happens in a dynamic environment

when does a firm disclose product information a firm chooses a price and the product information it discloses to a consumer whose tastes are privately known we provide a necessary and sufficient condition on the match function for full disclosure to be the unique equilibrium outcome whatever the costs and prior beliefs about product and consumer types it allows for products with different qualities as well as some horizontal match heterogeneity with independently distributed product and consumer types full disclosure is always an equilibrium and a necessary and sufficient equilibrium condition is that all firm types earn at least the full disclosure profit

asymmetric information in cattle auctions the problem of revaccinations the authors acknowledge the help of chris boessen glenn grimes joe horner robert larson k c olson and kurt richter this revision is dated july 2004

costly buyer search in a differentiated products model an experimental study this study examines whether the content of buyer information and the timing of its dissemination affects seller market power we construct laboratory markets with differentiated goods and costly buyer search in which sellers simultaneously post prices the experiment varies the information on price or product characteristics that buyers learn under different timing assumptions pre and postsearch generating four information treatments theory predicts that price information lowers the equilibrium price but information about product characteristics increases the equilibrium price that is contrary to intuition the presence of informed buyers may impart a negative externality on other uninformed buyers data support the model s negative externality result when sellers face a large number of robot buyers that are programmed to search optimally observed prices conform to the model s comparative statics and are broadly consistent with predicted levels with human buyers however excessive search instigates increased price competition and sellers post prices that are significantly lower than predicted

pricing product diversity and search costs a bertrand chamberlin diamond model we study price competition in the presence of search costs and product differentiation the limit cases of the model are the bertrand paradox the diamond paradox and chamberlinian monopolistic competition market prices rise with search costs and decrease with the number of firms prices may initially fall with the degree of product differentiation because more diversity leads to more search and more competition equilibrium diversity rises with search costs while the optimum level falls so entry is excessive the market failure is most pronounced for low preference for variety and high search costs

spatial price discrimination with heterogeneous products product heterogeneity is introduced into the context of spatial price discrimination many of the strong properties of the standard homogeneous goods case which are attained as a limit case here are shown to be no longer valid in particular the social optimum is no longer sustainable as a market equilibrium unless products are either identical or else very different

the burden of proof in a game of persuasion abstract an arbitrator faces the task of deciding the level of compensation to be received by a plaintiff from a defendant the arbitrator must rely on the verifiable submissions of the two interested parties because the information of the interested parties is not verifiable the unravelling argument has no force nevertheless a class of equilibria of this game gives rise to a particularly simple decision rule for the arbitrator which appeals to a probability distribution over the payoff relevant state space alone the uncertainty concerning the precision of the disputants information enter as parameters in this distribution this parametrization yields an answer to how the arbitrator s decision rule should be modified as the information of the disputants changes journal of economic literature classification numbers d78 d82 l51

consumer information and firm pricing negative externalities from improved information we analyze the effect of consumer information on firm pricing in a model where consumers search for prices and matches with products we consider two types of consumers uninformed consumers do not know in advance their match values with firms whereas informed consumers do prices are lower the greater the proportion of uninformed consumers hence uninformed consumers exert a positive externality on the others in contrast to standard results this leads to socially excessive investment in gathering prior information when aggregate demand is price sensitive

pure strategy nash equilibria in an advertising game with interference abstract two manufacturers produce substitutable goods for a homogeneous market the advertising efforts of the two manufacturers determine the demand for the goods and interfere negatively with each other the demand of each good is a piecewise linear function of the product goodwill and the latter is a linear function of advertising efforts in a game with two competing profit maximizing manufacturers who have access to a set of several advertising media the pure strategy nash equilibria are characterized and their existence is shown

lowering customer evaluation costs product differentiation and price competition when match uncertainty is resolved via costly evaluation the first product sampled by a customer is more likely to make the sale this prompts firms to lower their products evaluation costs to attract customers to sample their products first such efforts by firms are called customer learning investment cli when product quality is freely observable but horizontal match is not we examine how cli choices interact with quality and price competition in a duopoly cli has a competition effect in that a higher cli of a firm increases its demand but decreases that of its rivals in the market covered duopoly both qualities will decrease increase when the high end low end firm invests more in customer learning and remain unchanged when they invest equally relative to when neither firm invests we further show that the firm with a higher relative production efficiency invests more in customer learning than the competitor in the market not covered duopoly cli by the low end firm also creates a market

search design and market structure the internet has made consumer search easier with consequences for prices industry structure and the kinds of products oered we explore these conse quences in a rich but tractable model that allows for strategic design choices a polarized market structure results where some rms choose designs aimed at broad based audiences while others target narrow niches such an industry structure can arise even when all rms and consumers are ex ante identical we analyze the eect of reduced search costs and nd results consistent with the reported prevalence of niche goods and the long tail and superstar phe nomena in particular the model suggests that long tail eects arise when there is a wide range of potential designs relative to vertical heterogeneity among rms

using laboratory experimental auctions in marketing research a case study of new packaging for fresh beef this paper illustrates the use of laboratory experimental auctions in a pretest market research program for new products we review the experimental auctions literature discuss the range of auction mechanisms available and present the advantages and disadvantages of using a particular mechanism for a laboratory pretest market we then present a step by step example of how a theoretically incentive compatible auction mechanism fifth price sealed bid was used in a laboratory pretest market for vacuum packaged beef based on the illustration we discuss the potential for using laboratory experimental auctions in pretest market research we present the limitations that may be encountered in such applications and outline research aimed at improving the behavioral properties of the technique

the importance of taste in experimental auctions consumers valuation of calorie and sweetener labeling of soft drinks a majority of purchases that consumers make are classified as repeat purchases one of the main reasons why consumers make repeat food purchases is the food s taste therefore we examined the importance of including taste testing in nonhypothetical experimental auctions specifically we used two experiments to determine consumers willingness to pay for soft drinks labeled with different calorie and sweetener information in experiment 1 participants tasted the soft drinks prior to the bidding rounds in experiment 2 participants did not taste the soft drinks prior to the bidding rounds bidding behavior for the soft drinks was significantly different between experiment 1 and experiment 2 results suggest that including taste testing in the design of experimental auctions is important to accurately capture consumers willingness to pay for foods that are purchased repeatedly results also imply that policies aimed at combating obesity by making the calorie content of foods more visible may not produce desired outcomes

the character of demand in mature organic food markets great britain and denmark compared abstract we investigate the organic food market in two selected european countries great britain and denmark identifying main differences and similarities we focus particularly on consumer perceptions and priorities labelling schemes and sales channels as a basis for assessing market stability and prospects for future growth we employ a unique set of household panel data that includes information on stated values and concerns as well as registered purchasing behaviour most organic food on both markets is produced and processed by large scale industrialised units and distributed through mainstream sales channels consumer confidence being sustained at present by organic labelling schemes that appear to function well however a parallel market based on the supply of goods through various direct sales channels to heavy users prevails we find that organic food purchase decisions are primarily motivated by private good attributes such as freshness taste and health benefits attributes that may be perceived as being compatible with modern production and sales structure mature markets for organic foods nevertheless appear to be vulnerable to consumer dissatisfaction particularly among heavy users of organic food products

nudges that hurt those already hurting distributional and unintended effects of salience nudges abstract nudges are becoming increasingly popular policy tools yet distributional effects of nudges are largely unknown we first design an economic laboratory experiment to examine the incidence of an opportunity cost reminder nudge a salience nudge designed to curb spending while accounting for heterogeneity in emotional responses specifically the pain of paying pain of paying is optimal for unconflicted consumers but too low for spendthrifts and too high for tightwads causing sub optimal spending our empirical results imply the nudge increases pain of paying for tightwads thereby reducing spending by tightwads who already spend too little while it entirely fails to reduce the spending of those who would have benefited from a spending reduction spendthrifts overall the nudge therefore might reduce consumer welfare we next examine if the adverse impact of the opportunity cost reminder nudge is explained by a general tendency for all nudges to exacerbate peoples underlying spending preferences we specifically test whether a salience nudge designed to boost spending correspondingly adversely affects spendthrifts we unexpectedly find that subjects perceive the spending booster nudge as a spending reminder which again reduces spending by tightwads only while not affecting spending by the other consumer types our results highlight two important aspects of salience nudges given the complexity of consumer emotions and information processing salience nudges can have undesired welfare effects and the direction of their impact may be the opposite of what was intended

comparative advertising disclosing horizontal match information improved consumer information about horizontal aspects of products of similar quality leads to better consumer matching but also to higher prices so consumer surplus can go up or down while profits rise with enough quality asymmetry though the higher quality and hence larger firm s price falls with more information so both effects benefit consumers this occurs when comparative advertising is used against a large firm by a small one comparative advertising as it imparts more information therefore helps consumers although it also improves the profitability of the small firm overall welfare goes down because of the large loss to the attacked firm

a model of labeling with horizontal differentiation and cost variability we study optimal disclosure of variety by a multiproduct firm with random costs the prices for labeled varieties are increasing functions of the cost differential and do not reveal which variety is cheaper to produce nondisclosure is most common under moderate uncertainty about costs and not too much idiosyncrasy in valuations and quality asymmetry mandatory disclosure decreases expected welfare when cost variability is large and quality asymmetry is small the cheaper variety tends to be oversupplied undersupplied when disclosure is voluntary mandatory competition among multiproduct firms that source inputs in the same upstream market may not lead to more disclosure

persuasive puffery sellers often make claims about product strengths without providing evidence even though such claims are mere puffery we show that they can be credible because talking up any one strength comes at the implicit trade off of not talking up another potential strength puffery pulls in some buyers who value product attributes that are talked up or emphasized while pushing away other buyers who infer that the attributes they value are relative weaknesses when the initial probability of making a sale is low there are more potential buyers to pull in than to push away so puffery is persuasive overall this persuasiveness requires that buyers have some privacy about their preferences so that the seller does not completely pander to them more generally the results show how comparative cheap talk by an expert to a decision maker can be credible and persuasive in standard discrete choice models used throughout marketing economics and other disciplines

hypothetical actual bid calibration of a multigood auction abstract evidence suggests the calibration of hypothetical and actual behavior is good specific we examine whether clustering commodities into mutual categories can reduce the burden while we reject a common calibration across sets of commodities a sport specific calibration function cannot be rejected

aggregation and imperfect competition on the existence of equilibrium we present a new approach to the theory of imperfect competition and apply it to study price competition among differentiated products the central result provides general conditions under which there exists a pure strategy price equilibrium for any number of firms producing any set of products this includes products with multi dimen sional attributes in addition to the proof of existence we provide conditions for uniqueness our analysis covers location models the characteristics approach and probabilistic choice together in a unified framework to prove existence we employ aggregation theorems due to prekopa 1971 and borell 1975 our companion paper caplin and nalebuff 1991 introduces these theorems and develops the application to super majority voting rules we present a new approach to the theory of imperfect competition and apply it to study price competition among differentiated products the central result is that there exists a pure strategy price equilibrium for any number of firms producing any set of products in addition to the proof of existence we provide conditions for uniqueness our model both unites diverse strands of the earlier literature and opens up uncharted areas for future analysis in particular we expand the traditional one dimensional framework to allow for multi dimen sional product differentiation our approach involves twin restrictions on consumer preferences one on individuals preferences the other on the distribution of preferences across society these are generalizations of the restrictions supporting 64 majority rule presented in caplin and nalebuff 1988 to prove existence we apply a new technique of aggregation this technique is valuable in a variety of other problems in the companion paper we use the aggregation result to generalize our earlier work on 64 majority rule and to characterize the relationship between the distribution of human capital and the distribution of income caplin and nalebuff 1991 there are additional applications in statistics and in search theory we begin with a brief review of the early literature on imperfect competition describing in more detail the existence problem and previous solutions section 3 presents our twin assumptions and shows that they cover many standard cases in section 4 we introduce the aggregation theorem and use it in the analysis of demand functions the proof of existence of equilibrium is in section

a market based approach to child nutrition mothers demand for quality certification of infant foods in bamako mali this paper analyses the potential impact of introducing quality certification to the market for infant foods in a very low income country where malnutrition is widespread using an experimental economics approach we find that a program to sample test and certify the nutrient density of products could promote a more competitive market for low cost fortified foods and be implemented on a self financing basis yielding net economic benefits on the order of us 1 million per year in the city of bamako we find that mothers demand for quality information rises with their education and income level but is higher than the estimated cost of certification even among the very poor and uneducated