a model of temporary search market equilibrium abstract in the literature on search markets agents know the distribution of prices or learn about it through short run bayesian updating even though the first assumption is unrealistic and the empirical evidence emphasizes learning in the intermediate and long runs in this paper a new search markets theory is developed where agents have beliefs about the distribution of prices based on finitely many of its moments and past market experiences the main results are the existence of a hicks grandmont temporary equilibrium that the equilibrium correspondence has a closed graph and sufficient conditions for price dispersion a simple example illustrates the main ideas journal of economic literature classification numbers d83 l13

competition and the number of firms in a market are duopolies more competitive than atomistic markets this paper uses a variant of the standard search model to examine market equilibrium and the consequences for market equilibrium of an increase in the number of firms if marginal search costs increase with the number of searches then the demand curve facing any firm will be kinked with the elasticity of demand with respect to price decreases being less than with respect to price increases prices may not change in response to changes in marginal costs as the number of firms increases the maximum price that is consistent with equilibrium increases to the monopoly price but the minimum price decreases on the other hand if marginal search costs decrease with the number of searches equilibrium if it exists is characterized by a

feer for the cfa franc we investigate the behaviour of the real effective exchange rates reer of the two cfa franc zone monetary unions cemac and waemu vis a vis their long run equilibrium paths a reduced form of the edwards 1989 fundamentals equilibrium exchange rate feer model is estimated using the johansen s 1995 cointegration methodology and equilibrium paths and associated misalignments are derived for the period 1970 to 2005 our results suggest that for both cemac and waemu the fundamentals account for most of the exchange rates fluctuation increases in the terms of trade government consumption and productivity tend to appreciate the exchange rate while increases in investment and openness tend to depreciate it at end of 2005 we find no evidence that either the cemac or waemu reers were significantly over valued which suggests that no exchange rate action is currently needed our analysis also reveals significant differences in the fundamentals marginal impact and speed of reversion to equilibr

is the cfa franc zone an optimum currency area summary in this paper we explore the features of the cfa franc zone and compare them to those of the economic and monetary union emu by operationalizing the criteria for an optimum currency area a structural vector autoregression method is used in modeling national outputs as determined by global regional and country specific shocks we find that domestic outputs of the cfa franc zone countries are strongly influenced by country specific shocks while regional shocks are far more important in european countries that have joined the emu the results suggest that the cfa franc zone countries are structurally different from each other and thus are more likely to be subjected to asymmetric shocks they do not appear to form an optimum currency area and the monetary union may have been a costly arrangement for the member countries unless they are compensated with some other benefits

does size matter reassessing the relationship between aquaculture and poverty in bangladesh abstract aquaculture has long been promoted by development institutions in bangladesh on the understanding that it can alleviate poverty most of this attention has focused on forms of the activity commonly referred to as small scale this article draws on concepts from the literature on agricultural growth and elaborates a typology of aquaculture based on relations of production which suggests that in bangladesh quasi capitalist forms of aquaculture may possess greater potential to reduce poverty and enhance food security than the quasi peasant modes of production generally assumed to do so the implications of this conclusion are explored

discrete equilibrium price dispersion an explicit solution of an equilibrium model with price setting firms and searching customers makes possible a number of comparativestatics predictions about how cost differences among firms search costs of customers and taxes will affect the mean and variance of the distribution of market prices another implication of the model is that a firm s demand depends on the difference between its price and the average price in the market

wage and price controls in the equilibrium sequential search model abstract in this paper we study the effects of wage and price controls on employment output and welfare in a simplified version of the benabou j econom theory 60 1993 140 equilibrium sequential search model with bilateral heterogeneity we show that a price ceiling increases output but the change in welfare depends on three effects the reduction in aggregate search costs the increase in surplus due to increased output and the transfer of production to the least efficient firm the model is formally identical to a standard equilibrium search model of the labor market so analogous results hold for the minimum wage

the effects of firm optimizing behaviour in matching models this paper considers a matching model of which the search behaviour of jovanovic 1979 and albrecht and jovanovic 1984 are special cases the nature of the generality is that each unemployed worker has more information than firms about his average productivity this results in wage offers falling over the length of an unemployment spell because a long spell is a signal of lower than average productivity the results of the paper are similar to the scarring effect of heckman and borjas 1980 and greenwald 1986 and the discouraged worker effect of schweitzer and smith 1974

search and consumer theory a consumer faces list prices for commodities but can buy one at a discount discounts vary randomly between sellers the number of quotations sought depends on list prices search costs and wealth this function is homogeneous of degree zero and provided some sufficient conditions are satisfied is increasing in wealth decreasing in search cost independent of the list price of the discounted commodity if indirect utility is multiplicatively separable increasing in the list price if the commodity is a necessity increasing in the list price of substitutes slutsky s equation is generalized to include search

price matching in a model of equilibrium price dispersion some sellers announce openly to prospective buyers that they will match any competitor s lower price on similar products this practice is visible among many retailers of consumer durables such as tv sets stereo components cameras and personal computers in more covert and informal forms price matching is ubiquitous it exists whenever individual sellers of a product are known to be generally willing to lower their prices when confronted by prospective buyers who can demonstrate information of lower prices elsewhere attempts to demonstrate and verify such information usually constitute part of the haggling process one often wonders will prices consumers ultimately pay indeed be lower with such haggling will apparently aggressive price matching strategies result in lower or higher equilibrium prices this paper deals with an environment in which information is not perfect and buyers engage in costly sequential search it will be shown that with price matching prices ultimately charged to consumers are higher the crucial assumption here is that buyers marginal search cost increases with the number of searches already performed with this assumption the main idea driving our results is as follows in the presence of increasing marginal search cost price matching encourages search therefore there will be more prospective buyers who will have performed a larger number of searches their marginal search cost will be higher on the average thus firms will be able to take advantage of this and charge higher prices but why would price matching encourage search if marginal search cost is increasing the answer lies in that price matching implies costless recall in sequential search models with consumers facing a known price distribution and constant marginal search cost whether recall is costless or costly is immaterial for then consumers optimal strategy is a constant reservationprice strategy implying that prices rejected earlier will never be acceptable the desire to recall never arises so that it does not matter to the searcher whether recall is costly or costless in such an environment firms do not have the incentive to offer price matching but as rothschild 7 has cautioned us the two assumptions of costly and costless recall are not always interchangeable they are not when marginal search cost is increasing for then if a consumer having a price

testing models of consumer search using data on web browsing and purchasing behavior using a large data set on web browsing and purchasing behavior we test to what extent consumers are searching in accordance to various classical search models we nd that the benchmark model of sequential search with a known distributions of prices can be rejected based on the recall patterns we observe in the data moreover we show that even if consumers are initially unaware of the price distribution and have to learn the price distribution observed search behavior for given consumers over time is more consistent with non sequential search than sequential search with learning our

search costs and equilibrium price dispersion in auctions a leading explanation for price dispersion in posted price markets is search costs we incorporate this insight into a model of competing second price auctions similar to ebay by doing so we extend the narrow literature on competing auctions to capture price dispersion and grow the already large literature on price dispersion to include auctions we provide evidence on search costs and price dispersion using data collected from ebay identifying search costs by exploiting a discontinuity in the visibility of auctions due to ebay s search tool 1 we thank aaron bodoh creed greg lewis steve tadelis and various seminar participants for helpful comments nate woody for programming assistance and the cornell university institute for social sciences for financial support the views expressed herein are solely those of the authors and do not necessarily reflect those of the u s department of justice 1

improving developing country food security through aquaculture development lessons from asia abstract this paper provides a framework for examining aquaculture s linkages to food and nutritional security by elucidating key hypotheses concerning the role of aquaculture in household food and income systems in developing countries taking examples from developing asia where aquaculture showed a steady growth over the last decade the implications of aquaculture development are examined from the standpoint of its impact on employment income and consumption analysis revealed clear evidence of positive income and consumption effects of aquaculture on households however employment effects are still not significant the context of targeting small scale and subsistence oriented farmers as a means of improving food security in the developing countries has also been analyzed by identifying key socio economic and policy factors affecting aquaculture adoption and its impact on the poor the paper concludes that national policies for aquaculture development will need to concurrently address the food security and poverty questions more sharply than has been done at present by providing institutional and infrastructure support for access to resources such as land and water and to markets by poor households finally more empirical evidence should be collected on the varied opportunities aquaculture would provide to improve the income employment and food consumption levels within households

can price dispersion be persistent in the internet markets we investigate pricing behaviour and market dynamics for both online branches of multi channel retailers mcrs and online only retailers dotcoms based on a set of panel data collected for 2 years in the online dvd market we find that prices of mcrs and dotcoms both go down with time but prices of mcrs decrease in a significantly faster speed implying that difference in the average prices between the two types of retailers is getting smaller with time we also compare the price dispersion and its dynamics between mcrs and dotcoms we find that the price dispersion among mcrs is much bigger than that among dotcoms at the beginning but such a difference gets smaller with time as the price dispersion among dotcoms becomes bigger our results suggest that the two types of retailers will not only charge similar average prices in long term but also have similar price dispersions but our findings show that price dispersion among all retailers goes up with time indicating that prices do not converge in

minimum prices in a model with search frictions and price posting in this paper i consider the effects of a minimum price maximum wage in a random search model with price wage posting i show that with a minimum price the price distribution will have a mass point if the minimum price is sufficiently high the price distribution will become degenerate

an equilibrium model of search unemployment this paper develops a simple general equilibrium model with sequential search in which a nondegenerate wage offer distribution is endogenously determined we use this model to analyze the comparati

the impact of demand and price expectations on the behavior of prices the effects of demand and price expectations on price behavior are analyzed using data from the manufacturing sector and a model formulated to pinpoint the demand oriented factors affecting prices and to incorporate price expectations as a direct influence on price behavior the expected normal demand is seen to have a strong and systemic influence on price behavior the expected normal level of new orders is found to be an adequate measure with sector data in general although some industries require more specification the effects of inventories and unfilled orders on prices are sporadic and across sectors and industries demand oriented forces are concluded to perform as well statistically as cost push determinants expectations concerning the current normal industry price level have a significant and consistent impact on price behavior this supports the idea that firms setting prices take into account their estimates of competitor s prices future price expectations appear to have little effect on current price information 15 references

price dispersion with directed search we model a market where identical buyers direct their search to identical capacity constrained sellers sellers cannot fully commit to the list price so strategic bargaining may determine the sale price we study search and pricing behavior in symmetric equilibrium sale prices exhibit equilibrium dispersion as they respond naturally to local demand conditions uncoordinated search decisions lead to equilibrium demand heterogeneity so sellers realizing large demand bargain prices up we characterize the sale price distribution parametrically studying how different commitment limitations and market features affect pricing and surplus shares we also determine endogenously

measuring the effects of search costs on equilibrium prices and profits abstract this paper assesses the effects of search costs on equilibrium prices and profits using an estimated model of demand and costs in a laundry detergent market i find that some firms profits initially rise and then fall with search costs overall the magnitude and direction of the search costs effects on prices and profits are heterogeneous this is because search costs create conflicting incentives for a firm to reduce prices to attract the attention of searching consumers yet also raise prices to harvest profit from consumers who are unaware of competing products these effects can vary with the relationship between the firms actual prices and the consumers pre search beliefs about prices

retail gasoline price dynamics and local market power using monthly data from the 48 contiguous states except nevada for the 1988 2002 period it is shown that retail gasoline prices respond faster to wholesale price increases than to equivalent wholesale price decreases moreover markets with high average retail wholesale margins experience a slower adjustment and a more asymmetric response since gasoline is the only variable input average margins in a state likely reflect the degree of retail market power this suggests that sticky prices and response asymmetries in the gasoline market are at least partially a consequence of retail market power

employer search training and vacancy duration we develop a model of optimal employer search strategy when information about match quality is endogenous the model is tested using four data sets two of which have not previously been used as theory predicts we find that when filling positions requiring more training employers search more intensively and extensively employers also search more extensively when hiring workers with more education and with prior experience these findings provide strong evidence of systematic variation in search strategies based on the characteristics of the positions and job applicants factors that influence employer search also affect the duration of a vacancy

costly diagnosis and price dispersion abstract in the standard search model under monopolistic competition when the consumer encounters a seller he knows the price before purchasing the commodity consequently the price cannot exceed the consumer s reservation price in a market with rational and homogeneous agents the price distribution must therefore be degenerate in markets for indivisible professional services the consumer does not necessarily know the price of the service when he encounters the seller this possibility arises when the cost of ascertaining the price the diagnosis cost is high and the consumer decides to enter the market without searching in contrast to the standard model under monopolistic competition price dispersion in equilibrium is possible even when fully rational economic agents on both sides of the market are homogeneous we characterize such equilibria and provide a sufficient condition for their existence we then study the effect of manipulating the search technology typically through a professional code of ethics on the equilibrium in markets for such professional services

price dispersion in an automobile insurance market from automobile insurance data for alberta over the period 1974 81 we find thatpremiums are highly correlated across driver classes in a given year but that premiums for a given driver class are not correlated over a period of more than 5 years firms relative market shares among drivers over age 25 and married males under 25 are inversely related to their deviations from the mean premiums in these driver classes the variance of real premiums decreases with the numberof firms in the market and increases with the real loss cost per car insured and the number of cars insured from these results we conclude that the price dispersion in automobile insurance in alberta is based on costly consumer search

turning a blind eye costly enforcement credible commitment and minimum wage laws in many countries non compliance with minimum wage legislation is widespread and authorities may be seen as having turned a blind eye to a legislation that they have themselves passed but if enforcement is imperfect how effective can a minimum wage be and if non compliance is widespread why not revise the minimum wage this paper examines a minimum wage policy in a model with imperfect competition imperfect enforcement and imperfect commitment and argues that it is the combination of all three that produces results which are consistent with a wide range of stylized facts that would otherwise be difficult to explain within a single framework we demonstrate that turning a blind eye can indeed be an equilibrium phenomenon with rational expectations subject to an ex post credibility constraint since credible enforcement requires in effect a credible promise to execute ex post a costly transfer of income from employers to workers a government with an objective function giving full weight to efficiency but none to distribution is shown paradoxically to be unable to credibly elicit efficiency improvements via a minimum wage reform

number of sellers average prices and price dispersion abstract a variety of models provide differing predictions regarding the effect of an increase in the number of competitors in a market seller density on prices and price dispersion we review different approaches to generating equilibrium price dispersion and then empirically estimate the relationship between seller density average product price and price dispersion in the retail gasoline industry using four unique gasoline price data sets controlling for station level characteristics we find that an increase in station density consistently decreases both price levels and price dispersion across four geographical areas

output price markups and producer size abstract this paper examines how output prices and markups vary across the size distribution of producers it uses unique plant level data on physical output revenue and input expenditures for six homogeneous u s manufactured products the results reveal that for five of the six products output prices decline systematically with increases in plant size in the most extreme case corrugated boxes the smallest producers have prices that average 20 percent above the mean price while the largest producers average 10 percent below the mean at the other extreme the price dispersion for gasoline is small and unrelated to plant size plant specific markups of price over marginal cost vary across the size distribution of producers for five of the products in three cases they decline in two cases they increase and one product gasoline shows no systematic variation

experimentation and competition abstract this paper examines the effect of competition on firms efforts to experiment and learn about market demand consumers are assumed to know prices only at sellers they have actually visited but must bear search costs to find the prices of other sellers under these conditions we show that firms incentives to experiment are diluted by comparison with the monopoly case and that this effect is stronger the smaller the search cost the learning environment we portray gives rise to several time paths which have been empirically documented including penetration pricing cream skimming and cyclical pricing journal of economic literature classification numbers c73 d43 d83

equilibrium price distributions equilibrium price distributions for a homogeneous product consistent with individual incentives are investigated they arise in informationally imperfect markets in which the only primitive datum is the distribution of search costs it is shown that single multi and continuous price distributions are all viable long run phenomena depending on the nature of search costs a method for computing equilibrium price distributions is also provided jevons law of one price has long been an accepted dictum in economic theory in a classroom presentation it still serves sometimes implicitly as a major premise in many micro models of market interaction much of the descriptive theory as well as welfare analysis hinges on this assumption yet one s day to day experience reveals that price differentials are a viable phenomenon and that looking for lower prices may very well be a rewarding activity the prospects of eventually hitting a bargain and the resulting price reduction would more than compensate for the cost incurred during the search process moreover the existence of price dispersions appear to be an empirically stable phenomenon snapshots of markets for relatively homogeneous products reveal substantial and recurring price differentials stigler 1961 and pratt wise and zeckhauser 1979 for example report some evidence supporting this claim an important article by stigler 1961 focused economists attention on the crucial role played by the informational structure of markets it gave rise to the study of the

nonstandard foundations of equilibrium search models abstract we develop an equilibrium sequential search model which includes most of the literature as special cases in particular the model can accommodate heterogeneity in buyers search costs and demand functions and firms cost functions with general demand and cost functions we identify conditions which ensure existence of equilibrium in pure strategies utilizing recent progress in the theory of large games by khan and sun these conditions elucidate the essential structure of equilibrium search models although we focus on sequential search our methodology can be used for other classes of equilibrium search models as well

relationship between spatial agglomeration and hotel prices evidence from business and tourism consumers abstract in this paper we examine the relationship between number of local competitors and both the average and the dispersion of retail prices in urban hotels using a dataset from the metropolitan area of madrid spain by controlling for hotel characteristics and spatial factors we obtained results for each of the days in one week in line with predictions derived from the traditional monopolistic approach empirical results consistently indicate that a greater density of competitors implies a lower average and less dispersion of local prices moreover we found evidence which supports the idea that the effect of local agglomeration on average prices is particularly weaker at weekends this in turn indirectly suggests that within the metropolitan area there is a greater degree of substitution in hotel locations for tourism consumers than for business consumers

advertising intensity and welfare in an equilibrium search model i analyze an equilibrium search model in a duopoly setting with bilateral heterogeneities in production and search costs in which firms can advertise by announcing price i compare the market advertising level to the socially optimal level where i find that costly search can improve welfare and that firms may under or over advertise relative to the social optimum depending on the costs of search the results suggest that in markets with sufficiently low search costs firms are likely over advertising relative to the socially optimal level and vice versa for markets with sufficiently high search costs

oligopolistic pricing with sequential consumer search n identical stores compete by choosing prices for a homogeneous good with constant marginal costs consumers search sequentially with perfect recall for the lowest price one class of consumers called shoppers have zero search costs while all other consumers have a positive search cost c there is a unique symmetric nash equilibrium price distribution with the property that it changes smoothly from marginal cost pricing when all consumers are shoppers and or c 0 and monopoly pricing when no consumers are shoppers remarkably as the number of stores increases the nash equilibrium becomes more monopolistic copyright 1989 by american economic association

paying the professor sources of salary variation in academic labor markets using a set of 58 academic fields as distinct labor markets we examined the extent of wage variation within markets the degree to which wages vary is an indicator of market efficiency and of whether a market wage exists holding constant differences in human capital we found that the degree of wage variation in an academic labor market is negatively related to mobility within that market and positively related to the oversupply of labor we also found that as wage variation increases male female wage differentials also increase

rethinking aquaculture for resource poor farmers perspectives from bangladesh expectations about the unfulfilled potential of aquaculture as a source of animal protein for the poor of bangladesh are currently running high evidence suggests that social and economic constraints to intensification are as yet poorly understood and may constitute an important barrier to improving resource utilisation both public sector agencies and ngos are currently engaged in a range of aquaculture initiatives this paper critically surveys a selection of ongoing aquaculture research and extension programmes it is suggested that current approaches are unlikely to benefit those with low incomes in bangladesh since there are problems with both the conceptualisation of the problem of aquaculture and the types of institutional arrangements being deployed to tackle it the paper ends with several recommendations about future priorities in terms of the nature and style of aquaculture research

austrian style gasoline price regulation how it may backfire in january 2011 a price regulation was established in the austrian gasoline market which prohibits firms from raising their prices more than once per day similar restrictions have been discussed in new york state and germany despite their intuitive appeal this article argues that austrian type policies may actually harm consumers in a two period duopoly model with consumer search i show that under the regulation firms will distort their prices intertemporally in such a way that their aggregate expected profit remains unchanged this implies that as some consumers find it optimal to delay their purchase due to expected price savings but find it inconvenient to do so a friction is introduced that decreases net consumer surplus in the market

a simple model of price dispersion abstract this article considers a simple stock flow matching model with fully informed market participants unlike the standard matching literature prices are assumed to be set ex ante when sellers pre commit themselves to sell their products at an advertised price the unique equilibrium is characterized by price dispersion due to the idiosyncratic match payoffs in a marketplace with full information this provides new insights into the price dispersion literature which instead commonly assumes that buyers are not perfectly informed and engage in a costly search

tracking customer search to price discriminate suppose that every time you walked around the mall somebody put a bar code on your shoulder and as you walked into the shops in the mall someone came up and scanned your shoulder and got the number went to a database saying ah yes that s lesley who visited the shop next door 15 minutes ago that s the level of surveillance that s going on on the internet internet entrepreneur jason catlett in a 60 minutes interview with lesley stahl not as private as you think aired november 28 1999 i introduction transaction mechanisms in an electronic marketplace can be much different from those used in traditional markets predominantly brick and mortar markets are described as sellers posting single offer prices that buyers either accept or reject through their purchase decisions without necessarily holding everything else constant two buyers each making concurrent purchases in the same store pay the same posted price for an identical item 1 in particular a buyer that has visited multiple rival stores receives the same price as a buyer that impulsively purchases without comparing any prices in contrast a combination of internet technologies makes it possible to identify the search history of potential customers online retailers generally make use of a standard programming device that produces electronic files to tag individual customers with a unique identification commonly referred to as cookies these small computer files are stored on the hard drive of the customer s computer developers created cookies so that a web site could maintain state even though the http protocol is stateless this allows a web site to recognize an individual and accommodate multiple item purchases from an internet retailer 2 an unintended consequence of this technology is that other web sites namely rival sellers could use a second internet device called a web bug to retrieve the identity of the internet domain that placed a cookie even though the specific information content of the cookie is typically encrypted two different types of web bugs can ascertain the search history of a customer a web bug is a graphic typically one pixel by one pixel in size on a web page and it is designed to monitor who is reading the web page web bugs are virtually invisible because they are uncolored and so small one type an executable web bug is a file that monitors a machine s traffic and hard drive and periodically sends the information back to the web site that planted the bug on the machine the second type is not physically located on the machine and uses a technology called scripts e g javascript activex and perl to scan a hard drive searching for files 3 4 because the process of identifying a customer and posting an offer price is electronic and immediate sellers on the internet can use this technology to post dynamic customer specific prices 5 however the major contributions to the rich literature on consumer search consider only models in which firms post a single price regardless of how informed the customer may be for example braverman 1980 varian 1980 stiglitz 1979 and salop and stiglitz 1977 assume that a consumer is either fully informed or completely unaware of other stores prices and that each firm posts a single price to any customer other work considers sequential consumer search but again each firm posts a single price regardless of how informed the customer may be see for example stahl 1989 stiglitz 1987 rob 1985 burdett and judd 1983 carlson and mcafee 1983 and wilde and schwartz 1979 6 this article explores the fundamental changes to traditional sequential customer search in posted offer markets when firms have the ability to track customers and price discriminate accordingly using controlled experimental markets we investigate how the ability to track customers and offer differentially informed customers different prices affects the prices that buyers receive in aggregate

equilibrium price dispersion in retail markets for prescription drugs this study seeks to establish the empirical importance of price dispersion due to costly consumer search by examining retail prices for prescription drugs posted prices in two geographically distinct markets are shown to vary considerably across pharmacies within the same market even after one controls for variation due to pharmacy differences pharmacy heterogeneity accounts for at most one third of the observed price dispersion the empirical analysis hinges on the observation that consumers incentives to price shop depend on characteristics of the drug therapy cross sectional patterns in price distributions across drugs are consistent with the predictions of a search model prices for repeatedly purchased prescriptions for which the expected benefits of search are highest exhibit significant reductions in both dispersion and price cost margins

strategic pricing consumer search and the number of firms discover prices there are three distinct price dispersed equilibria characterized by low moderate and high search intensity the effects of an increase in the number of firms on search behaviour expected prices price dispersion and welfare are sensitive i to the equilibrium consumers search intensity and ii to the status quo number of firms for instance when consumers search with low intensity an increase in the number of firms reduces search does not affect expected price leads to greater price dispersion and reduces welfare in contrast when consumers search with high intensity increased competition results in more search and lower prices when the number of competitors in the market is low to begin with but in less search and higher prices when the number of competitors is large duopoly yields identical expected price and price dispersion but higher welfare than an infinite number of firms a question that has received much attention in economic theory is how the number of competitors and market outcomes are related despite the existence of work showing the contrary see e g satterthwaite 1979 rosenthal 1980 the prediction that emerges from a market where firms interact in a cournot fashion has come to dominate economic thought namely that an increase in the number of competitors leads to larger aggregate production lower market price and improved market performance measured in terms of some social welfare criterion ruffin 1971 this paper challenges the generality of this belief by presenting an oligopoly model with consumer search where the equilibrium expected price may be constant increasing or nonmonotonic in the number of firms we present an economy with two types of consumers consumers who search for prices at no cost fully informed and consumers who must pay a fixed search cost for each price quotation they observe less informed 1 all buyers have the same willingness to pay for the good and buy either a single unit or nothing at all on the supply side of the market there are n firms producing a homogeneous good at constant marginal cost we analyse a one shot simultaneous move game firms set prices and consumers decide how many prices to search for at the same moment in time our model is essentially an oligopolistic version of burdett and judd 1983 where some consumers search costlessly in this model consumers search using a fixed sample size search strategy i e they choose the number of prices to observe before receiving any offer nonsequential search is appealing when consumers find it more advantageous to gather price information quickly morgan and manning 1985 this occurs when the search outcome is observed with delay and delay is costly for instance an mba graduate looking for a job 1 the presence in the model of consumers who search costlessly captures the fact that some people have a

queues not just mediocrity inefficiency in decentralized markets with vertical differentiation abstract we analyze a dynamic decentralized market with endogenous entry where in each period the active sellers supply one unit of an indivisible service at varying degrees of quality the customers that have entered the market are randomly matched with the active sellers and prices are set by complete information pair wise bargaining in its unique steady state the market leads to an excess diversity of quality and customers may have to suffer costly delays notably efficiency is not regained as per period delay costs disappear we also show that setting minimal quality standards such as licensing rules by a professional college will improve welfare and even consumer surplus relative to the free market whenever the inefficiency is caused by a large enough excess supply

the impact of collusion on price behavior empirical results from two recent cases abstract we use extended arch and garch models to examine the differences in the behavior of the first two moments of the price distribution during collusive and competitive phases of two recently discovered conspiracies citric acid and lysine according to our results the conspirators managed to raise prices by 9 and 25 cents per pound in the short run relative to non collusive periods also the variance of prices during the lysine conspiracy was lower and the variance of prices during the citric acid conspiracy was higher than during more competitive periods the proposed methodology may be used for antitrust screening and prosecution purposes

search costs and equilibrium price dispersion in auction markets abstract a leading explanation for price dispersion in posted price markets is search costs we incorporate this insight into a model of competing second price auctions similar to ebay by doing so we extend the narrow literature on competing auctions to capture price dispersion and grow the already large literature on price dispersion to include auctions we provide evidence on search costs and price dispersion using data collected from ebay identifying search costs by exploiting a discontinuity in the visibility of auctions due to ebay s search tool

the perverse effects of wage and price controls in search markets abstract this paper examines the effects of price ceilings and minimum wages on the performance of markets in which agents must invest in costly search to become informed about prices or wages in this context it is found that the market equilibrium may respond to changes in policy instruments in strikingly counterintuitive ways in particular the imposition of price ceilings and minimum wages may respectively result in consumer price increases and wage decreases thus an important implication of our analysis is that when unions fight to increase wages by raising the minimum wage they may paradoxically actually be reducing the average wage of its members

consumer protection and the incentive to become informed we discuss the impact of consumer protection policies on consumer incentives to become informed of the best deals available in the market in a market with costly consumer search we find that imposing a cap on suppliers prices reduces the incentive to engage in search with the result that prices paid by consumers both informed and uninformed may rise in a related model where consumers have the ability to refuse to receive marketing we find that this ability softens price competition and can make all consumers worse off

contribution of fisheries and aquaculture to food security and poverty reduction assessing the current evidence following a precise evaluation protocol that was applied to a pool of 202 articles published between 2003 and 2014 this paper evaluates the existing evidence of how and to what extent capture fisheries and aquaculture contribute to improving nutrition food security and economic growth in developing and emergent countries in doing so we evaluate the quality and scientific rigor of that evidence identify the key conclusions that emerge from the literature and assess whether these conclusions are consistent across the sources the results of the assessment show that while some specific topics are consistently and rigorously documented thus substantiating some of the claims found in the literature other areas of research still lack the level of disaggregated data or an appropriate methodology to reach consistency and robust conclusions more specifically the analysis reveals that while fish contributes undeniably to nutrition and food security the links between fisheries aquaculture and poverty alleviation are complex and still unclear in particular national and household level studies on fisheries contributions to poverty alleviation lack good conceptual models and produce inconsistent results for aquaculture national and household studies tend to focus on export value chains and use diverse approaches they suggest some degree of poverty alleviation and possibly other positive outcomes for adopters but these outcomes also depend on the small scale farming contexts and on whether adoption was emergent or due to development assistance interventions impacts of fish trade on food security and poverty alleviation are ambiguous and confounded by a focus on international trade and a lack of consistent methods the influences of major drivers decentralization climate change demographic transition are still insufficiently documented and therefore poorly understood finally the evaluation reveals that evidence based research and policy narratives are often disconnected with some of the strongest and long lasting policy narratives lacking any strong and rigorous evidence based validation building on these different results this paper identifies six key gaps facing policy makers development practitioners and researchers

a model of market power in customer markets we develop a model for studying dynamic competition in environments with frictions that lead to partial lock in of customers to products the dynamic aspects associated with customer retention and acquisition introduce pricing incentives that do not exist in more traditional static product markets the proposed model while highly stylized maintains certain symmetry properties that allow us to obtain equilibrium existence and uniqueness we then study the comparative statics of the model and derive a closed form relationship between average equilibrium markups and the herfindahl index we illustrate how the model can be used by analyzing mergers in such a dynamic environment

consumer discrimination and self employment self employment rates and incomes differ significantly by race we show that these differentials arise in markets with consumer discrimination and incomplete information about the price of the good and the race of the seller equilibrium income distributions have two properties mean black incomes are lower than mean white incomes and the returns to ability are lower for black than for white sellers able blacks therefore are less likely to self select into the self employment sector than able whites using the 1980 census data we find that observed racial differences in the self employment income distributions are consistent with the theoretical predictions

price price dispersion and number of sellers at a low entry cost shopbot abstract shopbots function as market intermediaries by providing unprecedented quantities of information to buyers and sellers this paper explores the role of market structure across shopbot mediated markets using an unbalanced panel of 399 digital camera models it extends prior work by using an ultra low entry cost site additionally allowing controls for life cycle and popularity effects we find a robust negative relationship between seller number and price which persists even as markets become crowded with sellers the results are capable of either an scp or a carlson mcafee heterogeneous cost interpretation but observed entry behaviour here is consistent with the latter

an experimental study of price dispersion abstract we report an experiment examining a simple clearinghouse model that generates price dispersion according to this model price dispersion arises because of consumer heterogeneity some consumers are informed and simply buy from the firm offering the lowest price while the remaining consumers are captive and shop based on considerations other than price in our experiment we observe substantial and persistent price dispersion we find that as predicted an increase in the fraction of informed consumers leads to more competitive pricing for all consumers we also find as predicted that when more firms enter the market prices to informed consumers become more competitive while prices to captive customers become less competitive thus our experiment provides strong support for the model s comparative static predictions about how changes in market structure affect pricing

wine retail price dispersion in the united states searching for expensive wines similar to other markets in which deviations from jevons law of one price is the norm rather than the exception the retail wine market in the united states is characterized by large price dispersions drawing on a large sample of retail prices from wine searcher com we find an average per wine coefficient of variation of 23 percent some of this is due to differential market conditions especially state regulations our evidence suggests that dispersion also depends positively on price levels after controlling for consumer market and state heterogeneity

product differentiation search costs and competition in the mutual fund industry a case study of s p 500 index funds we investigate the role that non portfolio fund differentiation and information search frictions play in creating two salient features of the mutual fund industry the large number of funds and the sizeable dispersion in fund fees in a case study we find that despite the financial homogeneity of s p 500 index funds this sector exhibits the fund proliferation and fee dispersion observed in the broader industry we show how extra portfolio mechanisms explain these features these mechanisms also suggest an explanation for the puzzling late 1990s shift in sector assets to more expensive and often newly entered funds an influx of highinformation cost novice investors

buyer search and price dispersion a laboratory study we study markets with costly buyer search in which sellers simultaneously post prices buyers costlessly observe one or with probability 1 q two of the posted prices and can accept one or pay to search again the experiment varies q the search cost and the number of buyers equilibrium theory predicts a unified very low high price for q 0 q 1 and predicts specific distributions of dispersed prices for q 1 3 and 2 3 actual prices conform closely to the predictions in some treatments buyers reservation prices are biased away from the extremes however and sellers prices have positive autocorrelation and cross sectional correlation

on the adequacy of monetary arrangements in sub saharan africa we examine the economic rationale for monetary union s in sub saharan africa through the use of cluster analysis on a sample of 17 countries the variables used stem from the theory of optimum currency areas and from the fear of floating literature it is found that the existing cfa franc zone cannot be viewed as an optimum currency area cemac and uemoa countries do not belong to the same clusters and a core of the uemoa can be defined on economic grounds the results support the inclusion of the gambia ghana and sierra leone in an extended uemoa arrangement or the creation of a separate monetary union with the core of the uemoa and the gambia rather than the creation of a monetary union around nigeria finally the creation of the west african monetary zone wamz around nigeria is not supported by the data

market structure and market performance in e commerce we investigate the effect of market structure on market performance in the market for consumer electronics we exploit product life cycle information to build an instrumental variable for the number of firms in a market a variable which hitherto had to be treated as exogenous in comparable studies on seller behavior in e commerce we combine data from austria s largest online site for price comparisons with retail data on wholesale prices provided by a major hardware producer for consumer electronics we observe input prices of firms and all their moves in the entry and the pricing game using this information for 70 digital cameras we generate instrumenting is particularly important for estimating the effect of competition on the markup of the price leader

entry and price dynamics in a perfect foresight model abstract this paper studies firms entry and price dynamics in a model that combines the assumptions of free entry and perfect foresight with the hypothesis of consumer s loyalty postulated by phelps and winter the analysis of the transition to long run equilibrium reveals that in such a model the entry of firms is related to the difference between current prices and costs in relation to the growth of the firms output it is shown that the model is consistent with gibrat s law finally it is shown that the size distribution of firms approaches asymptotically a pareto distribution

price distributions and competition considerable evidence demonstrates that significant dispersion exists in the prices charged for seemingly homogeneous goods this paper adopts a simple flexible equilibrium model of search to investigate the way the market structure influences price dispersion using the noisy search approach the paper demonstrates the effects of having a single large price leading firm with multiple outlets and a competitive fringe of small firms with one retail outlet each

income taxation in a frictional labor market a new model of wage dispersion is used to examine welfare aspects of income taxation the model retains the dynamics of wage posting models while exogenizing search effort therefore allowing more insight into policy issues the results highlight effects that standard analyses do not take into account the optimal income tax should depend on an incidence effect between workers and firms this incidence effect arises from firms trying to lower wages as much as possible an employment tax proves in certain cases to be the best method to encourage labor force participation

competitive two part tariffs as a response to differential rates of time preference the major focus of the nonlinear pricing literature has been to demonstrate how welfare in a monopoly can be improved through the use of a nonlinear payment schedule however nonlinear prices arise in many different markets this paper explores nonlinear price equilibria in which both multiple firms and price schedules exist these outcomes are driven by the use of a sustainability criterion for equilibrium and differential rates of discount as the motivating force for the formation of nonlinear prices copyright 1991 by the london school of economics and political science

firm size distribution testing the independent submarkets model in the italian motor insurance industry this paper tests the presence of multiple independent submarkets in the italian motor insurance industry independence is motivated by administrative boundaries among provinces and by further locational reasons we find that the independence effects are sufficient to induce a minimum degree of inequality in the size distribution of firms once submarkets are aggregated these results are fully consistent with the predictions of sutton 1998 we also show that the degree of skewness in the firms size distribution is related to characteristics such as the population living in an area its density and the riskiness of a submarket

is aquaculture pro poor empirical evidence of impacts on fish consumption in bangladesh summary aquaculture is widely held to contribute to poverty reduction and food security in the global south but robust evidence is limited using nationally representative data from bangladesh this study analyses changes in fish consumption from 2000 to 2010 rapid expansion of commercial aquaculture pegged down fish prices resulting in increased fish consumption by extreme poor and moderate poor consumers and those in rural areas these outcomes are closely linked to the pro poor nature of national economic growth during this period these findings contribute to a broadening of the debate on whether the growth of aquaculture in bangladesh has been pro poor