dynamic project selection and funding under risk a decision tree based milp approach abstract this paper presents a mixed integer linear programming milp model for a new class of dynamic project selection and funding problems under risk given multiple scarce resources of different qualifications the underlying stochastic decision tree concept extends classical approaches mainly in that it adds a novel node type that allows for the continuous control of discrete branching probability distributions the control functions are piecewise linear and are convex for the costs and concave for the benefits the milp model has been embedded in a prototype decision support system dss with respect to the proposed solution the dss provides complete probability distributions for both costs and benefits

comparison shopping as a simultaneous move game this paper analyzes simultaneous move models of comparison shopping it shows that the equilibria in wilde schwartz 1979 can be rationalized as symmetric mixed strategies in an appropriately defined game in which information acquisition costs are endogenous it also shown that in the simultaneous move version of salop stiglitz 1977 nonexistence of equilibrium is not a problem in fact a variety of forms of equilibria emerge in that model pure strategy mixed strategy and blends of the two copyright 1992 by royal economic society

embeddedness cooperation and popular economy firms in the informal sector this paper is motivated by empirical observations on popular economy firms pefs in the informal sector of santiago de chile these are labor managed firms embedded in popular milieu where cooperation between their members plays a central role this paper develops a partial equilibrium microeconomic theory of pefs first it endogeneizes the level of cooperation between the workers second it develops a static and a dynamic model to analyze whether embeddedness influences the behavior of the pef embeddedness is assumed to be captured by three different characteristics suggested by the empirical observations most of them influence the employment and income levels in the pef

do consumers search for the highest price oligopoly equilibrium and monopoly optimum in differentiated products markets we develop a model of search among substitutes for the best combination of commodity variant and price in which the structure of search costs is manipulable by the suppliers of these variants e g by joining an existing market or opening a new one we analyze the subgame perfect equilibria arising in a multistage game involving specialized firms choice of entry variant and price and we compare them to a multiproduct monopolist s optimal choice we show that equilibrium prices increase in the number of substitutes sold in one market and that in the situation considered here monopoly increases welfare

imperfect information monopolistic competition and public policy introduction ever since the pioneering work of george stigler 1961 and the provocative survey by michael rothschild 1973 economists have recognized that general equilibrium models yield competitive equilibria only by making strong assumptions about the information available to market participants in response to this difficulty theorists in recent years have developed a family of search equilibrium models that presuppose homogeneity and the absence of price discrimination and which also assume that information acquisition costs are positive for at least a subset of buyers on the basis of these and other assumptions the models attempt to show how price dispersion equilibria can arise solely as a result of the strategies that firms and consumers pursue one author summarized the results if information is costly each small firm obtains market power so that the relevant market structure with imperfect information is not per ect competition but rather monopolistic competition steven salop 1976 p 240

on optimal production and the market to book ratio given limited shareholder diversification our purpose is to examine a firm s optimal output decision and valuation when its shareholders hold a limited number of risky assets the primary theoretical result indicates that the market to book ratio is a function of the degree of shareholder diversification our theory suggests a negative relationship between a firm s market to book ratio and shareholder diversification

efficient informal trade theory and experimental evidence from the cape town taxi market informal sectors in developing countries are often thought of as responses to rigid and cumbersome market regulations in this paper i study informal trade as a first best outcome in the model i propose rigid regulations can be necessary to achieve efficiency even though they are always sidestepped the key assumption is that the regulations define the trading parties fall back position in case the informal bargaining process breaks down i set up a field experiment to test the model s mechanisms in the cape town market for metered taxis consistent with the model i find that sidestepping the regulations increase cost efficiency taxis take the shortest route the price is however unaffected suggesting informal bargaining leads to a pareto improvement

prices and qualities in markets with costly information this paper extends the seminal work of akerlof and salop and stiglitz in two directions i the sellers can select both the selling prices and quality levels of their good and ii the buyers can acquire price quality information about individual sellers at a cost we observe multiple price quality combinations in equilibrium which depend upon the distribution of information costs of consumers and upon whether quality or price or both are costly observable welfare comparisons of equilibrium are considered we show that welfare will be greater when price advertising is permitted

learning experimentation and the optimal output decisions of a competitive firm this paper considers the effect of learning from experience on the output decisions of a perfectly competitive firm faced with the demand uncertainty specifically a bayesian framework for expectations formation and demand forecasting by a perfectly competitive firm is presented focusing the analysis on the determination of optimal sequential output decisions it is shown that through output experimentation the experimenting firm will select a non myopic sequential policy and will tend to overproduce the exact magnitude of the overproduction and the economic value of experimentation are contingent upon model parameters and the length of the planning horizon

certification under oligopolistic competition in a symmetric duopolistic market where each firm s choice regarding certain quality attributes such as the environmental friendliness of its product is its own private information the extent of horizontal differentiation between firms plays a crucial role in a certifier s optimal certification policy under a non profit certifier it is always the case that both firms produce the highest quality and opt for certification this is also the case under a for profit certifier but only when the degree of horizontal differentiation is sufficiently high when horizontal differentiation is low the for profit certifier by charging a very high certification fee creates maximum vertical differentiation between firms as a result only one firm produces the highest quality and opts for certification whereas the other firm produces the lowest quality and does not opt for certification this asymmetry under a for profit certifier makes the market inefficient which provides one possible explanation for the existence of mostly non profit certifiers in such markets

monopolistic competition when price and quality are imperfectly observable consider the symmetric equilibrium of a monopolistically competitive industry in which manufacturers select price and quality to maximize expected profit and consumers maximize utility by conducting costly search among sellers using an optimal sequential search rule consumers search among sellers because i each consumer idiosyncratically evaluates each seller s quality and ii a retailing sector generates variation in the prices consumers pay consumers are handicapped in their search because their observations of firms price and quality levels are noisy an improvement in price information is represented by an increase in the precision with which consumers observe sellers prices similarly an improvement in quality information is represented by an increase in precision with which consumers observe sellers quality levels an improvement of either type of information may increase or decrease welfare the perverse case in which improved price information decreases welfare occurs when price competition among firms becomes so intense relative to quality competition that firms select severely suboptimal levels of quality a consumer searching among monopolistically competitive sellers may have difficulty accurately observing the price and quality of each seller s product he must infer from his prior beliefs and noisy observations the true values of the product s price and quality attributes we show that increasing the precision with which consumers observe an attribute of a product makes the inference problem easier and causes the demand the seller faces with respect to that attribute to become more elastic the equilibrium level of that attribute changes accordingly and since the equilibrium levels of price and quality interact the equilibrium level of the other attribute changes as well these equilibrium effects can be perverse in two ways first if the precision of quality observation is fixed then improvement in the precision of price observation can reduce welfare the chain of causation is this increasing the precision of price observation causes price to fall the resulting smaller price cost margin induces sellers to reduce quality de

oligopolistic competition in price and quality abstract we consider an oligopolistic market where firms compete in price and quality and where consumers have heterogeneous information some consumers know both the prices and quality of the products offered some know only the prices and some know neither we show that if there are sufficiently many uninformed consumers then there exists a unique equilibrium where price is a perfect indicator of quality this equilibrium is characterized by dispersion and pareto inefficiency of the price quality offers where better price quality combinations are associated with lower prices

costly buyer search in laboratory markets with seller advertising in this experiment sellers simultaneously choose prices and advertising strategies buyers either purchase at an advertised price or search sequentially for other prices in the unique symmetric equilibrium sellers charge a high unadvertised price or advertise a price chosen from a lower interval increases in search or advertising costs raise equilibrium prices and affect equilibrium advertising intensity empirical results are consistent with most comparative static predictions sellers however price much lower and advertise more intensely than predicted consequently market outcomes more closely resemble a perfect information bertrand like equilibrium than the imperfect information mixed strategy equilibrium with significant seller market power

an experimental study of price dispersion in an optimal search model with advertising abstract this paper reports a laboratory experiment to study pricing and advertising behavior with costly buyer search sellers simultaneously post prices and may incur a cost to advertise this price in the unique symmetric equilibrium sellers either charge a high unadvertised price or randomize in an interval of lower advertised prices increases in search or advertising costs raise equilibrium prices and equilibrium advertising intensity decreases with lower search costs and higher advertising costs our experimental results support these comparative static predictions and sellers also post high unadvertised prices as predicted in all treatments however sellers advertise more intensely than in equilibrium

the effect of standardized information on firm survival and marketing strategies we argue that standardized information disclosure information using a common format and uniform metrics creates asymmetric opportunities for firms which affects their strategies and survival we test our predictions using a longitudinal quasi experimental field study involving the nutrition labeling and education act of 1990 nlea and we focus on firm market share within a category as a key asymmetry findings indicate that in general the nlea had no effect on firm responses however when accounting for firm differences we observe that the nlea led to 1 an increase in small share firm exits and 2 a greater increase in distribution for large share firms no concurrent increase in price by large share firms following the nlea was observed we conclude by discussing the implications of these effects for firm strategy the design of public policy and theories regarding the impact of information on markets

multi period inventory games with information update this paper addresses the multi period inventory game of two substitutable products with learning in which the demand distribution form in each period is known but one or more parameters are unknown in advance the retailers update the estimates of the unknown parameters using the historical demand information as the transaction proceeds at each period the retailers check the initial inventories and update the forecasts about their demands first then they place the orders which are delivered immediately finally the demands are realized and satisfied by the available inventories the unsatisfied demand of one retailer switches to another and is satisfied by the other s left inventory unsatisfied demand is lost and the excess inventories incur a holding cost all the information is common knowledge the objectives of the two retailers are to make proper ordering decisions to maximize their total expected discount profits respectively we model the problem as a dynamic bayesian game with multi dimension state space we give the conditions under which the state space can be reduced we prove the existence and uniqueness of nash equilibrium and show that the equilibrium ordering strategy is the base stock policy the computation of the base stock levels can be reduced to a game with one dimension state space moreover for the case with perishable product the computation of the base stock levels can be reduced to the newsboy game

forecasting and inventory management of short life cycle products in this paper we provide an integrated framework for forecasting and inventory management of short life cycle products the literature on forecasting and inventory management does not adequately address issues relating to short life cycle products we first propose a growth model that can be used to obtain accurate monthly forecasts for the entire life cycle of the product the model avoids limiting data requirements of traditional methods instead it extracts relevant information from past product histories and utilizes the information on total life cycle sales and the peak sales timing using disguised demand data from a personal computer pc manufacturer we validate the model next we model the inventory management problem for the short life cycle environment the uncertainty in demand is modeled through the uncertainty in the realized values of the parameters of the forecasting model the high cost of terminal inventory shortages and rapidly changing procurement costs are all included in the model extensions to the basic model are also developed using optimal control theory we derive a solution that provides valuable information on procurement cutoff time and terminal service levels a detailed example explains the characteristics of the policy and its relevance in decision making many of the issues covered in the models were brought to our attention while implementing a forecasting model at a pc manufacturer the benchmark monthly forecasts and the associated inventory levels provide information that can be very helpful in planning and controlling marketing sales and production

membership and employment in an egalitarian cooperative economic models of the labour managed firm often stress inefficiencies and perverse behaviour in his seminal work ward 1958 considers a firm in which dividend not profit is maximized dividend is defined as value added net of fixed costs divided by the number of workers for the short run problem with the capital stock fixed ward shows that the usual demand signals would induce perverse responses i e contraction expansion when demand increases decreases workers will not move between firms to equate marginal products of labour and the dividend maximizing firm will respond to an increase in fixed cost by increasing the number of workers these results are disconcerting in that they cast doubt on product market stability due to downward sloping supply curves on the achievement of an efficient allocation of resources and on the formulation of consistent policy prescriptions in a labour managed economy ward s fundamental result that dividend maximization leads to a contraction expansion of the number of workers in the firm as output price increases decreases is remarkably robust it has its analogue in the multi product firm domar 1966 it is not eliminated when labour leisure considerations are introduced ireland and law 1981 and it applies to variations in expected price when uncertainty is introduced bonin 1980 however the appropriateness of modelling the producer cooperative as a firm in which the number of workers can be varied freely to maximize dividend has been criticized robinson 1967 and vanek 1969 argue that a true collective would not dismiss some of the brethren in exchange for small increments in the income of the remaining members interestingly this solidarity position can be supported by the individual self interest maximizing behaviour of a representative member bonin 1981

observation bias the impact of demand censoring on newsvendor level and adjustment behavior in an experimental newsvendor setting we investigate three phenomena level behavior the decision maker s average ordering tendency adjustment behavior the tendency to adjust period to period order quantities and observation bias the tendency to let the degree of demand feedback influence order quantities we find that in three of four conditions the portion of mismatch cost that results from adjustment behavior exceeds the portion of mismatch cost caused by level behavior observation bias is studied through censored demand feedback a situation that arguably represents most newsvendor settings when demands are uncensored subjects tend to order below the normative quantity when they face high margin and above the normative quantity when they face low margin but in neither case do they order beyond mean demand the pull to center effect censoring in general leads to lower quantities magnifying the below normative level behavior when they face high margin but partially counterbalancing the above normative level behavior when they face low margin violating the pull to center effect in both cases data as supplemental material are available at http dx doi org 10 1287 mnsc 2013 1825 this paper was accepted by christian terwiesch operations management

price quality and timing of moves in markets with incomplete information an experimental analysis this paper reports the results of theoretical and experimental analyses of search models of shopping behavior earlier work which dealt with markets for homogeneous goods in which sellers first determined their prices and buyers then decided upon their information acquisition shopping strategies conditional upon the distribution of prices showed that nash equilibria for these markets were good predictions of outcomes of laboratory experiments the authors extend the analysis to markets with heterogeneous goods and allow buyers and sellers to move simultaneously the results of a series of laboratory experiments indicate that the nash equilibria continue to be good predictions in these more realistic settings copyright 1992 by royal economic society

advance production in posted offer markets abstract data from market sessions in which production is to demand are compared with data from sessions requiring that output decisions be made and production costs incurred prior to the start of trading in each period no inventory carry over is permitted differences in aggregate output measures such as average contact price sales and market efficiency tend to disappear as traders gain experience in an unchanging environment however the addtional risk introduced by the sunk cost aspect of advance production appears to offset any advantage regarding sellers share of the surplus conferred by the power to post prices

advance production in oral double auction markets abstract the effects of advance production in oral double auction markets are investigated price distributions under advance production ap and production to demand td conditions do not differ however production and efficiency in ap markets tend to be lower than in td markets

on the employment decision of a labour managed firm the conventional analysis of a variable membership labour co operative assumes that membership can be reduced if required to increase income per head see for example vanek 1970 this implies a highly inequitable treatment of those who are excluded compared with those who remain we prefer instead to consider a decision process suggested by steinherr and thisse 1979 which treats all members ex ante equitably we assume that a co operative first votes on whether to reduce membership or not and then allocates any resulting redundancies randomly in section ii we define a range of conditions in which a cooperative will not vote to reduce membership although contraction would raise income per head for those remaining since voters who face the possibility of exclusion will take this into account in section iii we present the implications of these results for the supply functions of the firm and show that supply depends on initial membership that supply curves may not be reversible and that they may contain discontinuities kinks and backward sloping segments even with a smooth underlying technology a more general conclusion to be drawn is that a satisfactory theory of labour managed firms should rest on an analysis of decision making procedures and not on the imputation of an arbitrary maximand to the firm as a whole

using game theory to model competition the article is an exposition of the basic concepts of noncooperative game theory and their application to advertising product and price competition

consumer search costs and market performance i introduction one of the seminal developments leading to the information economics revolution in the 1970s and 19c0s was diamond s 1971 theoretical result that in the absence of publicly posted price information the existence of even a small search cost could lead to monopoly pricing the intuition is straightforward no buyer with one price quote would want to search for a second unless it is likely that the buyer would encounter a price reduction that covers the search cost thus each seller has an incentive to price slightly above any common price and the noncooperative equilibrium in a single stage game yields a monopoly price this result is viewed as a paradox since a small search cost produces high prices but a zero search cost would produce the usual bertrand incentives that drive prices to competitive levels in the absence of capacity constraints and other imperfections 1 recent theoretical work has focused on finding a resolution to the paradox stahl 1989 for example generates a smooth transition between competitive and monopoly outcomes as the fraction of consumers with zero search costs increases from zero to one interestingly stahl finds that increasing the number of sellers makes pricing more monopolistic holding the number of informed buyers constant bagwell and ramey 1992 propose an alternative resolution that applies to an infinitely repeated market game where sellers who raise prices can develop a reputation that can affect sales in future periods bagwell and ramey show that buyers can obtain lower equilibrium prices by following a loyalty boycott search rule where low pricing sellers are rewarded with repeated purchases and high pricing sellers are punished with switching the price predictions vary continuously between monopoly and competitive levels depending on the size of the consumer search cost the policy relevance of the diamond paradox depends on whether there are realistic market environments in which small reductions in the availability of price information can cause large price increases 2 due to the difficulty of controlling and measuring information flows in natural markets the laboratory represents an ideal place to evaluate the diamond paradox and proposed resolutions the only experimental analysis of these issues is reported by grether schwartz and wilde 1988 who observed monopoly pricing in three of four predicted cases these results are suggestive but not definitive for reasons discussed below in particular as grether schwartz and wilde 1988 328 observe all four cases involved the same group of subjects to the extent possible this paper reports an experiment consisting of twelve market sessions designed to assess the effects of public price information the markets are conducted as normal posted offer markets except that buyers must pay a small cost each time they approach a different seller in baseline posted offer treatments all prices are publicly displayed to buyers while in search treatments prices are not publicly displayed in brief we find that prices approach competitive levels under the posted offer treatment and prices are significantly higher under the search treatment nevertheless the diamond prediction of monopoly pricing under search is not observed although increases in search costs do raise prices these results indicate that economists should take a more careful look at attempts to resolve the diamond paradox by introducing other factors that may impede monopoly pricing in markets with consumer search the paper is organized as follows our two primary treatments are outlined in section ii and results are presented in section iii the failure to observe the diamond monopoly price prediction motivated additional research on the effects of reputations and search costs which is presented in section iv the final section contains a conclusion ii

quality indicators in theory and in fact abstract in recent literature it has been suggested that consumers need have no knowledge of product quality as a number of quality indicators or signals may be used as substitutes very little attention has been paid to the empirical verification of these studies the present paper is devoted to the issue of how well these indicators perform using market data provided by consumer magazines from 3 countries the results strongly indicate that price is a poor quality indicator the paper also presents some evidence which suggests that seller reputation and easily observable characteristics are also poor indicators

the censored newsvendor and the optimal acquisition of information this paper investigates the effect of demand censoring on the optimal policy in newsvendor inventory models with general parametric demand distributions and unknown parameter values we show that the newsvendor problem withobservable lost sales reduces to a sequence of single period problems while the newsvendor problem withunobservable lost sales requires a dynamic analysis using a bayesian markov decision process approach we show that the optimalin ventory level in the presence of censored demand ishigher than would be determined using a bayesian myopic policy we explore the economic rationality for this observation and illustrate it with numerical examples

is more competition always better an experimental study of extortionary corruption using a laboratory experiment we assess whether increasing competition among public officials reduces extortionary corruption we find that increasing the number of providers has no effect on bribe demands when citizens search costs are high but it increases corruption when search costs are low the effect is absent in a parallel setting framed as a standard market which we attribute to citizens using a nonsequential search strategy as opposed to sequential search in the corruption setting we conclude that efforts to reduce search costs such as infrastructure investments are preferable to anti corruption policies aimed at increasing the number of providers jel d73 d49 c91

uncertainty and shopping behaviour an experimental analysis this paper reports experimental tests of three search equilibrium models these models which differ only in the search strategies available to the buyers have qualitatively different predictions that is equilibria price distributions single price equilibria at the competitive price and at the monopoly price and two price equilibria the experimental outcomes generally were consistent with the models predictions this suggests that debate on the utility of this class of models should shift to the realism of the models assumptions rather than focus on their ability to characterize market outcomes also since the basic models have been validated the project of analyzing experimentally the results of relaxing some of their assumptions seems worthwhile

market structure and the durability of goods a basic proposition in microeconomics is that a monopolist tends to produce less output than would be produced by a competitive industry with this proposition in mind it is tempting to suggest that monopolistic producers of durable goods will produce goods with less durability than would be produced by a competitive industry this result was derived by martin 1962 kleiman and ophir 1966 levhari and srinivasan 1969 and schmalensee 1970 however swan 1970 showed that monopolists would choose the same degree of durability for their goods as would competitive producers the reason that earlier writers had reached a different result was that they had focused on long run equilibrium profits and ignored the role of initial conditions in optimizing decisions the swan independence result that durability is independent of market structurewas first derived under the assumption of constant returns to scale specifically the average cost of production was assumed to be an increasing function of durability but independent of the level of output the constant returns to scale assumption was first relaxed by sieper and swan 1973 by introducing a fixed capacity cost they showed that with finitely lived capacity which required replacement the independence result continued to hold in the very long run although market structure could affect durability before attainment of long run equilibrium no systematic results were derived kamien and schwartz 1974 introduced rising average cost curves and resurrected the result of earlier writers that a monopolist would choose a lower durability than competitive firms however swan 1977 pointed out that the kamien schwartz analysis is flawed by not allowing the monopolist access to the same technology as the competitive industry if the monopolist is allowed to choose the optimal number of plants then swan s independence result holds finally auernheimer and saving 1977 introduced costs of adjusting the rate of output and the durability of output they showed that if long run increasing costs arise from pecuniary external diseconomies then the independence result is preserved as remarked by schmalensee 1979 in his survey the general message of

scarf s state reduction method flexibility and a dependent demand inventory model we consider a finite horizon inventory model with linear holding shortage and ordering costs the demand random variables are dependent and average demand is described by an exponential smoothing formula this model can be formulated as a two state variable inventory level weighted past demands dynamic program using a procedure first developed by scarf for a bayesian inventory model we are able to reformulate the model as a one state variable dynamic program resulting in a considerable computational saving over the two state variable formulation we also show that this dependent demand model orders less than or equal the amount ordered by a comparable independent demand model we establish this result under the assumption that demand represents failures that are repaired by the beginning of the next period

experimentation and optimal output decisions the cooperative versus the entrepreneurial firm this paper studies and contrasts the experimental inclinations of entrepreneurial and cooperative firms supplying a perishable good under uncertain demand when larger stocks might yield additional information about the demand generating process while these firms might react differently and in the case of the cooperative not unambiguously to environmental change neither variant will find the higher output possibly more informative option especially attractive

entry strategies of partnerships versus conventional firms from 1997 to 2001 the number of nonemployer businesses mostly partnerships grew faster than conventional firms in the united states a country with the mildest asymmetries between the two types of enterprises with respect to taxation administrative entry barriers and other institutional aspects partnerships are smaller than conventional firms and their different speeds of net entry could be the result of internal organization that makes them swifter and better equipped to be fast growing industries in a continuous time stochastic environment with sunk costs we model entry as a growth option partnerships and conventional firms display specific patterns in terms of output price and size in that they appear to react in diverse fashions to market uncertainty in most cases the partnership is less risky and better suited to enter under conditions of high volatility as between 1997 and 2001 in the united states

behavior of participatory firms in yugoslavia lessons for transforming economies this paper develops a multiparty model of enterprise behavior with the management workers and government authorities being the decisionmakers the model captures the behavior of yugoslav enterprises in the 1970s and 1980s enterprises in transitional economies and public sector bargaining in western countries estimating the model on yugoslav firm level data from the 1970s and 1980s indicates that the perverse behavior predicted by the ward domar vanek model of labor managed firms is not supported by the data as firms place emphasis on both wages and employment a direct test shows that the employment response to output price changes is insignificant coauthors are jan svejnar dubravko mihaljek and vesna prasnikar copyright 1994 by mit press

advance production in experimental markets the effects of advance production in posted offer and double auction markets are investigated previously observed differences between these institutions in mean contract prices and in the distribution of producers and consumers surpluses under the production to demand condition disappear when sellers make output decisions and incur production costs prior to the start of trading the double auction institution remains more efficient under advance production the results suggest that the differential effects of alternative trading institutions on market outcomes may be partially offset by the production conditions characterizing a market

productivity effects of worker participation in management profit sharing worker ownership of assets and unionization in u s firms abstract in this paper we provide our first econometric estimates of the effect of worker participation in decision making ownership and profits on productive efficiency participation has the potential for exerting several conflicting influences on firm performance simultaneously as a result both the direction and magnitude of its impact are empirical issues previous studies have empirically measured the impact of each of these forms of participation however no prior study has controlled for the influence of the other forms because of the potential for correlation among these forms of participation it is possible that omitted variables bias has affected the previous results using a new panel data set with simultaneous measures of all four types of participation in u s manufacturing establishments we model participation as disembodied technical change and estimate production function coefficients for each type while controlling for the others we use both ols and instrumental variables in order to guard against potential simultaneity the iv results indicate that participation in decision making has a large positive productivity effect while the impacts of unionization and profit sharing depend upon regression specification moderate amounts of indirect worker ownership affect productivity positively while the estimated effect of direct worker ownership is negative however this last result may reflect the industrial concentration of the direct ownership firms in our sample

forecasting realized volatility a bayesian model averaging approach summary how to measure and model volatility is an important issue in finance recent research uses high frequency intraday data to construct ex post measures of daily volatility this paper uses a bayesian modelaveraging approach to forecast realized volatility candidate models include autoregressive and heterogeneous autoregressive specifications based on the logarithm of realized volatility realized power variation realized bipower variation a jump and an asymmetric term applied to equity and exchange rate volatility over several forecast horizons bayesian model averaging provides very competitive density forecasts and modest improvements in point forecasts compared to benchmark models we discuss the reasons for this including the importance of using realized power variation as a predictor bayesian model averaging provides further improvements to density forecasts when we move away from linear models and average over specifications that allow for garch effects in the innovations to log volatility copyright 2009 john wiley sons ltd

product quality and imperfect information this paper considers markets in which consumers are imperfectly informed about both product prices and quality levels offered by firms we characterize necessary and sufficient conditions for existence of the various equilibrium configurations of price and quality that can arise in two paradigm cases when all consumers prefer higher quality and when all consumers prefer lower quality our results suggest that firms will exploit imperfect information by charging noncompetitive prices as well as by offering other than ideal quality in the former case but only by changing noncompetitive prices in the latter case

a generalized model of pricing for homogeneous goods under imperfect information this paper generalizes the model developed in wilde and schwartz 1979 to allow downward sloping demand curves and u shaped average cost curves it shows that the basic qualitative conclusions of wilde and schwartz still hold moreover it shows that the critical proportion of comparison shoppers needed to generate a competitive equilibrium falls as demand becomes more elastic or average costs become more inelastic finally it shows that when imperfect information generates non competitive outcomes they are bounded below in welfare terms by the monopolistically competitive equilibrium

fair trades by trade fairs information providing institutions under monopolistic competition it is a standard result of search theory that the optimal reservation supply price e g wage is negatively correlated to search costs this paper applies the inverse relationship between demand prices and limit prices to the analysis of an hitherto unexplored topic trade fairs trade fairs bloomed during the middle ages and early trade based capitalism and survived for centuries in last decades their growth became sustained they attract every year hundreds of thousands of exhibitors and tens of millions of visitors

middlemen in bilateral search markets this article examines the role of middlemen in bilateral search markets e g employment agencies real estate brokers it is shown that the middleman narrows the set of buyer firm and seller worker types who search seller types with high valuations and buyer types with low valuations drop out of the search market and instead trade through the middleman the middleman also decreases the equilibrium search intensities of those agents who search it is proven that the middleman improves welfare if search is very costly and inefficient and decreases welfare if search is effectively costless and very efficient

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

learning consumer tastes through dynamic assortments how should a firm modify its product assortment over time when learning about consumer tastes in this paper we study dynamic assortment decisions in a horizontally differentiated product category for which consumers diverse tastes can be represented as locations on a hotelling line we presume that the firm knows all possible consumer locations comprising a finite set but does not know their probability distribution we model this problem as a discrete time dynamic program each period the firm chooses an assortment and sets prices to maximize the total expected profit over a finite horizon given its subjective beliefs over consumer tastes the consumers then choose a product from the assortment that maximizes their own utility the firm observes sales which provide censored information on consumer tastes and it updates beliefs in a bayesian fashion there is a recurring trade off between the immediate profits from sales in the current period exploitation and the informational gains to be exploited in all future periods exploration we show that one can partially order assortments based on their information content and that in any given period the optimal assortment cannot be less informative than the myopically optimal assortment this result is akin to the well known stock more result in censored newsvendor problems with the newsvendor learning about demand through sales when lost sales are not observable we demonstrate that it can be optimal for the firm to alternate between exploration and exploitation and even offer assortments that lead to losses in the current period in order to gain information on consumer tastes we also develop a bayesian conjugate model that reduces the state space of the dynamic program and study value of learning using this conjugate model

stochastic trends deterministic trends and business cycle turning points this study examines the relationship between specifications for long run output patterns and specifications for business cycle dynamics in an application to us gdp it is found that inferences about the nature of the trend in output are not robust to changes in the specification for short run fluctuations similarly the choice of which model best describes the transitory movements in output depends on the way in which the trend is specified the empirical analysis makes use of bayesian methods to compare time series models for us gdp inspection of the predictive densities for the individual data points suggests that the information contained in the data is largely limited to the observations associated with business cycle turning points 1997 john wiley sons ltd

prices product qualities and asymmetric information the competitive case recent developments in the economics of information emphasize the informational content of prices we examine the degree to which prices convey information on product quality to uninformed agents under perfect competition we show that a rational expectations equilibrium may not exist when an equilibrium does exist the information on quality conveyed by prices depends on the shape of the average cost curves and the relative numbers of informed and uniformed agents

stalking information bayesian inventory management with unobserved lost sales retailers are frequently uncertain about the underlying demand distribution of a new product when taking the empirical bayesian approach of scarf 1959 they simultaneously stock the product over time and learn about the distribution assuming that unmet demand is lost and unobserved this learning must be based on observing sales rather than demand which differs from sales in the event of a stockout using the framework and results of braden and freimer 1991 the cumulative learning about the underlying demand distribution is captured by two parameters a scale parameter that reflects the predicted size of the underlying market and a shape parameter that indicates both the size of the market and the precision with which the underlying distribution is known an important simplification result of scarf 1960 and azoury 1985 which allows the scale parameter to be removed from the optimization is shown to extend to this setting we present examples that reveal two interesting phenomena 1 a retailer may hope that compared to stocking out realized demand will be strictly less than the stock level even though stocking out would signal a stochastically larger demand distribution and 2 it can be optimal to drop a product after a period of successful sales we also present specific conditions under which the following results hold 1 investment in excess stocks to enhance learning will occur in every dynamic problem and 2 a product is never dropped after a period of poor sales the model is extended to multiple independent markets whose distributions depend proportionately on a single unknown parameter we argue that smaller markets should be given better service as an effective means of acquiring information

workers enterprises are not perverse we give a simple direct proof that workers enterprises i e firms whose workers and partners coincide behave properly as price takers adjusting employment and the supply of output in the same direction as the relative price of the product thus belying the usual theory in which labor managed firms tend to curtail employment and output in their short run response to an increase in output price the logic of our proof derives again from the common sense of the worker partnership market in workers and incentives sertel 1982

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

optimal sequential investment decisions under conditions of uncertainty this paper presents a mathematical model of sequential investment behavior under conditions of uncertainty the model addresses the problem of an investor with access to a limited pool of capital who makes sequential decisions on long lasting investments under uncertainty as to the timing or the quality of future opportunities we derive optimal investment strategies for the cases where the return from investment is a convex or concave function we present closed form solutions for commonly adopted return functions and we evaluate how the optimal investment behavior should change when changes occur in the environment or the underlying probability distributions in addition we analyze three modifications of the problem the results presented in this paper extend previous results on investment behavior for long lasting irreversible decisions in addition some results are in accordance with existing ones from portfolio theory and or search theory

dynamic portfolio selection of npd programs using marginal returns selecting program portfolios within a budget constraint is an important challenge in the management of new product development npd optimal portfolios are difficult to define because of the combinatorial complexity of project combinations however at the aggregate level of the strategic allocation of resources across product lines investment in a program is not an all or nothing decision but can beadjusted resulting in a higher or lower program benefit e g higher or lower quality in some cases resources can be adjusted even for individual projects with this insight one can usemarginal analysis to optimally allocate the scarce budget this article develops a dynamic model of resource allocation taking into account multiple interacting factors such as independent or correlated uncertain market payoffs that change over time increasing or decreasing returns from the npd investment carry over of the investment benefit over multiple periods and interactions across market segments we characterize optimal policies in closed form and derive qualitative decision rules for managers

the theory of the labour managed firm revisited the voluntary interactive approach membership in the authors labor managed firm is determined in the long run by expected income maximization in the short run upon the realization of output price each member may leave the labor managed firm however a decision to leave when the entire membership quits is associated with fixed cost this arrangement ensures ex post egalitarianism and sense of job security the authors short run result is that employment does not exhibit a perverse response to price variations the long run result is that their labor managed firm is more populous than the illyrian firm and may even be more than its capitalistic twin copyright 1993 by royal economic society

the stochastic knapsack revisited switch over policies and dynamic pricing the stochastic knapsack has been used as a model in wide ranging applications from dynamic resource allocation to admission control in telecommunication in recent years a variation of the model has become a basic tool in studying problems that arise in revenue management and dynamic flexible pricing and it is in this context that our study is undertaken based on a dynamic programming formulation and associated properties of the value function we study in this paper a class of control that we call switch over policies start by accepting only orders of the highest price and switch to including lower prices as time goes by with the switch over times optimally decided via convex programming we establish the asymptotic optimality of the switch over policy and develop pricing models based on this policy to optimize the price reductions over the decision horizon

product differentiation with imperfect information the paper employs a model of monopolistic competition and product differentiation with consumers who are not well informed about the specification of the offered brands welfare analysis of the degree of product differentiation in such a market concludes that the socially desirable product variety is limited due to consumers imperfect information consequently when the number of consumers is sufficiently large or economies to scale in production are sufficiently weak the market would offer excessive variety the literature on product differentiation is motivated by the observation that only some of the potential brands of a differentiated product are produced and sold it studies issues such as the role of the market structure in the determination of product diversity and the welfare performance of alternative markets in making this product selection for example see lancaster 1979 and salop 1979 in the spatial models tradition spence 1976 and dixit and stiglitz 1977 in the diversifying representative consumer tradition these studies model product selection as an equilibrium outcome of monopolistic competition the welfare analysis focuses on the tradeoff between consumer benefits which naturally increase with variety and production efficiency which owing to economies to scale decreases with variety they find no natural relation between the socially optimal variety and the market outcome the latter can be smaller or larger than the former depending on the parameters of the model although it is natural to expect that in some markets for differentiated products consumers are imperfectly informed about the available brands all these studies assume that consumers possess perfect information the present paper assumes that consumers are imperfectly informed and indeed obtains qualitatively different results first regardless of how significant are the production economies of scale the optimal variety is below a predetermined level that depends on the parameters of consumer utility and information second when consumer population is sufficiently large or economies to scale in production are sufficiently weak the market would offer excessive variety the explanation is that consumers imperfect information limits the extent to which they can exploit the variety offered in the market it is therefore a social waste to increase variety to a level that consumers cannot benefit from

business cycle asymmetries characterisation and testing based on markov switching autoregressions tests for business cycle asymmetries are developed for markov switching autoregressive models the tests of deepness steepness and sharpness are wald statistics which have standard asymptotics for the standard two regime model of expansions and contractions deepness is shown to imply sharpness and vice versa whereas the process is always nonsteep two and three state models of u s gnp growth are used to illustrate the approach along with models of u s investment and consumption growth the robustness of the tests to model misspecification and the effects of regime dependent heteroscedasticity are investigated