modeling inertia and variety seeking tendencies in brand choice behavior theories of exploratory behavior suggest that inertia and variety seeking tendencies may coexist within the individual implying that the same individual may exhibit inertia and variety seeking at different times depending on his her choice history past research has not allowed for such within consumer variability in these tendencies the purpose of this study is to present a choice model that allows us to identify such hybrid behavior i e a mixture of inertia and variety seeking and to distinguish hybrid behavior from simpler types of behavior such as pure inertia pure variety seeking and zero order behavior the model is estimated at the household level using panel data for three product classes covering a total of 1069 households the empirical analysis shows that more than half the households analyzed exhibited hybrid behavior rather than simpler types of behavior

modeling evaluation and methodology in the new century i what is changing it appears that any overt expression of interest in methodology is considered a clear sign of weak mindedness or premature senility l boland methodology entry in the new palgrave dictionary of economics as time passes one should expect the techniques and consequently the underlying methodology also to evolve this article will discuss some of the major changes in methodology since the middle of the last century to now among the major driving forces for this change is the growth in the amount of data available in most parts of economics together with the tremendous growth in the speed and storage ability of computers as well as the interactive aspects of the internet techniques or methodologies that were unthinkable or certainly unavailable 25 years ago are now standard and common a new mind set is required to limit dissension i will consider economics to be a decision science describing the decisions made by economic agents such as consumers employers investors and policy makers it follows that the purpose of any economic analysis will be to help actual decision makers make better decisions on average in a stochastic environment such an analysis can be thought of as a final good some analysis will be an intermediate good which helps another economist produce a better final good by taking these attitudes a pragmatic viewpoint can be taken in many situations and provide solutions to some questions as will be seen the many books and articles on economic methodology and philosophy in the past century consider many topics that were considered of considerable interest then but have since lost their importance for example a topic earlier viewed as being of some importance was is economics a science although i believe that it is no longer a hot topic around economics departments the answer to the question is that no one really cares however that may not be the correct response because if economics was classified as a science the discipline may be eligible for much larger research grants another major topic with a lasting impact was about whether a model needs an input of economic theory or not or equally can a satisfactory model be achieved just by introspection without any use of data i can recommend a very interesting short article on this topic titled methodenstreit or battle of the models by daniel fusfield in the new palgrave 1987 the battle was between carl menger and gustav schmoller starting in the 1880s with menger in favor of pure theory and schmoller wanting to use just an empirical approach unfortunately their initial debate became confused in a more political one with menger pushing laissez faire policies whereas schmoller supported interventionist government policy approaches essentially right versus left in today s terminology fusfield states that on the basic issue of the place of theory and empirical studies in economics menger and schmoller agreed that both were necessary they disagreed on the emphasis to be placed on each and their role in the development of conclusions menger correctly pointed out that a model based just on data is limited in generality because the data cover only some of the possible space it needs correct theory to go beyond the sample space he also said that data acted as a bridge between the principles of pure economics and the policy problems of applied economics in fact he warned against policy analysis without an empirical study schmoller was less generous to theorists finding the work too abstract irrelevant and based on assumptions that are unrealistic a later similar discussion took place between koopmans 1947 and burns and mitchell 1947 that influenced modeling into the 1960s and 1970s where do we stand 115 years later in this discussion in many ways it seems quite modern certainly compared to some of the remarks made around real business cycle theory a few years back

please or squeeze brand performance implications of constrained and unconstrained multi item promotions existing research on price promotions typically investigates the effects of single product promotions however brand managers often promote multiple items simultaneously to bolster the performance of a complete brand line this paper investigates the brand performance implications of such multi item promotions we distinguish between two types of multi item promotions traditional unconstrained multi item promotions that grant a discount irrespective of the size or composition of the purchase set and constrained multi item promotions that require consumers to purchase specific quantities self bundling or even predetermined combinations fixed bundling of promoted items using a normative consumer decision model the authors analyze the relative effectiveness of these promotions in terms of unit sales and revenue impact and show that promotion performance is moderated by consumers preference for variety the authors find that unconstrained multi item promotions outperform single item promotions especially in markets without variety seeking in markets with variety seeking unconstrained multi item promotions are not as effective in stealing extra sales from competition because consumers prefer to spread their purchases across all items including competitive ones however in those markets self bundling promotions are particularly effective because they force consumers to adopt larger amounts of the promoted items at the expense of competitors finally in neither type of market does fixed bundling substantially improve promotion performance

positive welfare effects of trade barriers in a dynamic partial equilibrium model we develop a simple two region cobweb type dynamic partial equilibrium model to demonstrate the existence of optimal possibly non zero trade barriers a pure comparative statics analysis of our model suggests that a reduction of trade barriers modeled as small but positive import tariffs always enhances welfare however taking a dynamic perspective reveals that nonlinear trade interactions between two regions may generate endogenous price fluctuations which can hamper welfare finally we allow special interest groups such as consumers or producers from these two regions to lobby for a particular level of trade barriers our model predicts that time varying trade barriers may be another channel for market instability

modeling purchase timing and brand switching behavior incorporating explanatory variables and unobserved heterogeneity the authors use a continuous time semi markov approach to analyze in a single framework the purchase timing and brand switching decisions of households for a frequently purchased product the analysis provides more insights into the dynamics of household purchase behavior than could be obtained from conventional discrete choice models such as logit or probit the authors find that the probability distribution of interpurchase times is not the same for various switching between brands revealing extra information about the purchase timing decisions further they find that though the marketing mix and household demographic variables explain a large part of the variation in the brand switching rates they account for only a small part of the variation in the repeat purchase rates another finding from the analysis is that the rates of switching between brands due to promotional activities such as special displays and price reductions are in reverse order to the share of purchases of the various brands

product and price competition with satiation effects consumers become satiated with a product when purchasing too much too quickly how much is too much and how quickly is too quickly depends on the characteristics of the product relative to the time interval between consumption periods knowing that consumers allocate their budget to products that generate less satiation effects retailers should then choose to sell products that induce minimal satiation but usually this is operationally more costly to study this trade off we provide an analytical model based on utility theory that relates customer consumption to price and satiation in the context of multiple competing retailers we determine the purchasing pattern over time and provide an explicit expression to determine the consumption level in steady state we derive market shares and show that they take the form of an attraction model in which the attractiveness depends on price and product satiation we use this to analyze the competition between firms that maximize long term average profit we characterize the equilibrium under three scenarios i price only competition ii product only competition and iii price and product competition the results reveal the interplay between a key marketing lever price and the firm s ability to offer products that generate less satiation in particular we show that when a firm becomes more efficient at reducing satiation its competitor may benefit if competition is on product only but not if it is on price and product we also find that when satiation effects are not managed a firm s profit may be significantly reduced while a strategic competitor can largely benefit this paper was accepted by yossi aviv operations management

a model of stochastic variety seeking in this paper we propose and test a stochastic model of consumer choice that incorporates attribute based variety seeking our stochastic variety seeking model svs has nested within it a fixed variety seeking model a zero order model of choice and a first order pure variety model we compare the svs model to alternative models under stochastic variety seeking we examine the nature of the variety sought and provide a test of the satiation hypothesis unlike fixed variety seeking models our model allows variety seeking to vary in intensity and consistency over individuals as well as over purchase occasions we show that the model is equivalent to a random utility model with the features that the attributes of brands relative to those of the brand previously bought influence choice and the extent of variety seeking is random over choice occasions for a given individual the model permits a closed form solution to the conditional switching probabilities parameterized by variety seeking parameters and dependent on brand attributes we apply our model to individual choice data obtained from a field study specifically designed for the purpose at hand

speed of replacement modeling brand loyalty using last move data abstract the authors study brand loyalties for durable goods using automobile survey data that are peculiarly censored and track only elapsed times since transitions but not the transition times themselves this censoring problem is typical of commercially available durable goods survey data however little attention has been paid to such last move data in the statistics or marketing literature on the analysis of transition times the authors propose a multistate continuous time nonstationary markov model with a parsimonious brand loyalty structure and also propose an estimation approach to recover the parameters of the proposed model using the automobile survey data the proposed model fits observed brand choice outcomes even better than a model with a fully unrestricted and therefore highly parameterized transition structure the authors also obtain several substantive findings for example chrysler is significantly weaker than general motors and ford insofar as it has the lowest brand loyal

english auctions with resale an experimental study i design and test a simple english auction and two english auctions with resale but with different informational backgrounds all three treatments theoretically have the same equilibrium i find however that the possibility of resale alters behavior significantly in the two treatments with resale subjects deviated from both the nash prediction and the common results about bidding behavior in english auctions subjects tend to overbid when they are certain they can reap the whole surplus in the resale market i employ different models like qre and levels of reasoning and conclude that overbidding can be explained as a rational response to the noisy environment in markets with human participants that is as rational decision making when anticipating others to make errors when the outcome of the resale market is not certain there is significant signaling behavior and auction prices tend to be lower than the nash prediction

product assortment in a triopolgy producers of super premium ice cream such as haagen dazs offer a smaller assortment of flavors than the producers of lesser quality ice cream examples of this phenomenon can be found in other industries as well in many industries the producers of higher quality products offer a smaller assortment of flavors colors sizes patterns textures fragrances tones styles models designs types or other options this paper explores when and why producers of super premium products should find it profitable to offer a smaller assortment than the producers of nonpremium products we derive a nash equilibrium both on prices and product assortments for a triopoly at the nash equilibrium we show that additional product quality increased consumer price sensitivity and greater assortment costs discourages product assortment we also show that a larger market potential greater competitive costs and sharper competition encourage more assortment by the super premium producer

asymmetric auctions with resale an experimental study we study auctions with resale based on hafalir and krishna s 2008 6 model as predicted weak bidders bid more with resale than without so that average auction prices tend to increase when the equilibrium calls for weak types to bid higher than their values with resale they do but not nearly as much as the theory predicts in other treatments outcomes are much closer to the risk neutral nash model s predictions bid distributions for weak and strong types are more similar with resale than without in line with the theory

variety seeking through brand switching a concept of variety seeking behavior is modeled as a stochastic brand choice model the model yields a measure of variety seeking for each individual consumer panel data for 28 products are analyzed for each household and the possibility of market segmentation by variety seeking behavior is explored

5 information impact and allocation rules in auctions with affiliated private values a laboratory study in affiliated private value auctions each bidder has perfect information regarding his her own value for the object at auction but higher values of the item for one bidder make higher values for other bidders more likely we report on a series of experiments examining three key implications of these auctions i in a first price auction public information about rivals values increases expected revenue ii an english auction increases expected revenue compared to a first price auction and iii a second price auction is isomorphic to an english auction in examining these issues we compare predictions of some ad hoc bidding models with nash equilibrium predictions in the first price auction experiments nash equilibrium bidding theory organizes the data better than either of two ad hoc bidding models public information about others valuations does increase average revenue but the increase in revenue is smaller and less reliable than predicted under risk neutral nash equilibrium bidding lower average revenue might be attributed to risk aversion while the high variability is attributed to a sizable frequency of individual bidding errors relative to the theory bidding theory precisely organizes english auction outcomes after a brief initial learning period the dominant strategy equilibrium does not organize second price auctions nearly as well as market prices persistently exceed predicted prices the difference between english and second price outcomes is attributed to effects of different information flows inherent in the structure of the two institutions on eliminating bidding errors revenue impacts of these two institutions relative to a first price auction are examined in light of observed bidding patterns

technical note aggregating individual purchases to the household level household level panel data are the input for many types of marketing studies an interesting but until now unaddressed question is what is the effect of aggregating individual members purchases to the household level under standard assumptions the answer is unambiguous the household brand switching pattern looks more zero order than the typical individual family member s behavior when the standard assumptions are relaxed the overall spirit of the results do not change these conclusions give comfort to those who use brand switching data to partition product categories those looking for variety seeking behavior from household data are given some cause for concern as well as reasons for reinterpreting previous studies

intertemporal aggregation of heterogeneous consumers abstract this paper deals with a relatively unexamined facet of stochastic brand switching models their connection to market share models we derive a composite market share model based on aggregation of heterogeneous markovian type individuals each purchasing a brand from the product class several times during the period of analysis the characteristics of this composite model are examined and interestingly suggest a markov type market share model moreover this examination sheds some light on a phenomenon uncovered in econometric studies of market share response to advertising the slow decay of the lagged market share term as the length of the measurement period is increased

an investigation into the order of the brand choice process this paper investigates the order of the brand choice process at the individual family level using a variety of tests t likelihood ratio binomial runs and multinomial runs tests the test of stationarity developed permits separate analyses for stationary and nonstationary purchase sequences our analyses indicate that the purchase sequences of a majority of stationary consumers are consistent with the zero order assumption this result is observed for all the nine frequently bought packaged goods studied with the use of panel data and for a product category soft drinks using experimental data

positioning and pricing in a variety seeking market we study competitive positioning and pricing strategies in markets where consumers seek variety variety seeking behavior is modeled as a decrease in the willingness to pay for the product purchased on the previous purchase occasion using a three stage hotelling type model we show that the presence of variety seeking consumers reduces product differentiation offered in equilibrium thereby explaining some otherwise counterintuitive findings in empirical research we find that firms charge higher prices in period 1 and lower prices in period 2 the lower price in period 2 represents the price incentive that firms need to offer to prevent the variety seeking consumers from switching furthermore we find that the observed switching in a market may not fully capture the true magnitude of the underlying variety seeking tendencies among consumers finally we show that the presence of variety seeking consumers leads to lower firm profits and a higher consumer surplus surplus increases for variety seeking consumers as well as regular consumers therefore the presence of variety seeking consumers benefits everyone in the market

testing for choice dynamics in panel data this article applies different approaches to distinguish state dependence from unobserved heterogeneity and serial correlation and hence test for state dependence in consumer brand choices first we apply a simple method proposed by chamberlain which involves lagged exogenous variables only second we also estimate a lagged dependent variable specification proposed by wooldridge third we use the estimation approach suggested by wooldridge to estimate a model with both lagged dependent and exogenous variables to distinguish between the two different sources of choice dynamics state dependence and lagged effects of the exogenous variables our analysis reveals that the best approach is to use models with both lagged dependent and exogenous variables our findings include strong evidence for state dependence in five out of the six product categories studied in this article

competitive market structures a subset selection analysis market structure models are used to identify submarkets or to test for the presence of submarkets where within group competition is much stronger than across group competition the implicit assumption in such models is that the brands in a submarket compete on the basis of their shared product features however if significant variety seeking effect exist in the market such an assumption may not be valid we present a model based on a subset selection procedure for analyzing competitive market structures and develop tests of significance for variety seeking effects present in the market for each brand in the market the subset selection procedure identifies sets submarkets of brands that are in close competition the competitive market structure is defined by the possibly overlapping submarkets that are identified for each brand and the model provides insights on whether the brands in a submarket are of a reinforcing or a variety seeking kind the application of our model to two different consumer packaged goods markets highlights its contribution relative to extant methods

niching versus change of pace brands using purchase frequencies and penetration rates to infer brand positionings the authors examine deviations from ehrenberg s wi 1 bi equal to a constant law to infer the positioning of low share brands as niche versus change of pace brands results from empirical anal

speculation and demand reduction in english clock auctions with resale many auctions are followed by a resale market which occurs when the winner of the auction resells the item won to one of the participants from the original auction the existence of such transactions may initially appear counter intuitive however this paper will show that active inter bidder resale results from payoff maximizing decisions in the auction that take into account the incentives of a resale opportunity specifically i examine how the existence of an inter bidder resale opportunity impacts bidder behavior in an english clock auction and to what extent altering the bargaining power of the final buyer and reseller in the resale market determines the strategies followed in the initial auction in an attempt to understand the existence of these inter bidder transactions theoretical and behavioral analysis is used to develop hypotheses of speculation bidding above value and demand reduction bidding below value which are directly tested in a controlled experimental setting while value bidding is a dominant strategy in a standard english clock auction without resale when resale is allowed this theoretical claim is weaker demand reduction is observed when the bargaining power is shifted to the final buyer in resale and when the bargaining power is shifted toward the reseller speculation is observed the revenue achieved in the initial auction depends on the behavior observed in the auction regardless of bargaining power revenue is shown to decrease below what would have been earned in an english auction without resale due to demand reduction when the reseller has the bargaining power and speculation is observed this loss in revenue is somewhat mitigated by increased speculation

inferring the order of the choice process using consumer purchase histories the small sample properties of the multinomial runs mr test which is often used to test for effects of previous brand choices on current brand choice probabilities are explored in this article through a monte carlo study of different buyer level brand choice probability models the power and the actual size of this test under a null hypothesis of no previous brand choice effects are shown to depend on the nature of the true underlying model length of purchase history and skewness in baseline choice probabilities we provide some guidelines for when the mr test is more useful in empirical research

chapter 6 market share models publisher summary this chapter describes that three basic principles motivate the specification of the market share models market share models should be competitive descriptive as well as predictive and profit oriented being fundamentally competitive implies that one cannot know the effect or effectiveness of a marketing action without accounting for the actions of competitors market share models are models for understanding how the marketing efforts of every brand impact the results in a competitive marketplace only by describing the influence of each marketing instrument can one gain a basis for marketing planning prediction alone is not enough time series models that forecast the future from the past sales provide no insight into how sales are generated the emphasis on being descriptive also embraces the need to understand the areas in which consumer choice probabilities are synonymous with market shares as well part of the goal of description transcends what can be done by market share models alone managers need to understand that their efforts have potentially competitive effects and potentially market expansive effects in sales response models these effects are comingled but by combining descriptive market share models for the competitive effects with descriptive category volume models for the market expansive effects managers obtain a much richer understanding of the market the profit oriented goal of market share analysis urges us to ask how the firm s allocations of resources to aspects of the marketing mix produce bottom line results

vertical differentiation with variety seeking consumers we analyze price and quality competition in a vertically differentiated duopoly in which consumers have a preference for variety the preference for variety is a consequence of diminishing marginal utility for repeated experiences with the same product we find consumer variety seeking can either soften or intensify price competition depending on the difference in firm qualities and the strength of consumer preference for variety when the qualities are similar or the consumer preference for variety is strong prices and profits are higher than would be obtained in the absence of variety seeking on the other hand if qualities differ enough or the preference for variety is weak stronger preferences for variety are associated with more intense price competition and lower profits when firms set their qualities before competing on price and the range of feasible qualities is restricted such that variety seeking softens competition competing firms choose to minimally differentiate themselves from each other the preference for variety can drive the firms to offer multiunit discounts and the greater price flexibility from these discounts does not necessarily reduce profits relative to simple unit pricing this paper was accepted by j miguel villas boas marketing

flexibility in consumer purchasing for uncertain future tastes consumers often simultaneously purchase multiple units in the same product category whether they are best off purchasing an assortment of alternatives or an equal number of one alternative is addressed in this paper models of an expected utility maximizing consumer are developed and it is shown that an assortment may have greater expected utility than an equal number of any one alternative the rationale is that the assortment allows the consumer to choose from inventory the alternative most appropriate for a consumption occasion using preference information not available at the purchase occasion it is also shown that when consuming alternatives from inventory the consumer may forego the alternative offering the most utility in the expectation that it will yield even more utility in the future

bidding to lose auctions with resale a losing bidder can still purchase the prize from the winner after the auction we show why a strong bidder may prefer to drop out of the auction before the price has reached her valuation and acquire the prize in the aftermarket a strong bidder may be in a better bargaining position in the aftermarket if her rival won at a relatively low price so it can be common knowledge that in equilibrium a weak bidder will win the auction and even without uncertainty about relative valuations resale will take place the possibility of reselling to a strong bidder attracts weak bidders to participate in the auction and raises the seller s revenue

the design testing and implementation of virginia s nox allowance auction we report on the design and testing of three auction mechanisms to maximize revenue and efficiency in the sale of two vintages of nitrous oxide emission allowances by the commonwealth of virginia in 2004 the three mechanisms considered were a combinatorial sealed bid csb auction a sequential english clock sec auction and a combinatorial english clock cec auction we find the sec and cec mechanisms to be superior the csb when demand is relatively elastic 2008 elsevier b v all rights reserved

collusion via resale the english auction is susceptible to tacit collusion when post auction interbidder resale is allowed we show this by constructing equilibria where with positive probability one bidder wins the auction without any competition and divides the spoils by optimally reselling the good to the other bidders these equilibria interim pareto dominate among bidders the standard value bidding equilibrium without requiring the bidders to make any commitment on bidding behavior or postbidding spoil division

speculation in standard auctions with resale in standard auctions resale creates a role for a speculator a bidder who is commonly known to have no use value for the good on sale we study this issue in environments with symmetric independent private value bidders for second price and english auctions the efficient value bidding equilibrium coexists with a continuum of inefficient equilibria in which the speculator wins the auction and makes positive profits first price and dutch auctions have an essentially unique equilibrium and whether or not the speculator wins the auction and distorts the final allocation depends on the number of bidders the value distribution and the discount factor speculators do not make profits in first price or dutch auctions

price competition in markets with consumer variety seeking we investigate price competition between firms in markets characterized by consumer variety seeking while previous research has addressed the effect of consumer inertia on prices there exists no research on the effects of variety seeking on price competition our study fills this gap in the literature using a two period duopoly framework as in klemperer s analysis of inertial markets we show that the noncooperative pricing equilibrium in a market with consumer variety seeking may be the same as the collusive outcome in an otherwise identical market without variety seeking specifically our variety seeking model implies tacit collusion between firms in both periods unlike the inertia model of klemperer that implies tacit collusion between firms only in the second period but implies fierce price competition in the first period when consumers are assumed to have rational expectations about future prices the implied first period prices increase further which is consistent with what klemperer finds in an inertial market to summarize while our variety seeking analyses support two key results pertaining to second period prices and rational expectations previously derived for inertial markets by klemperer they depart from one key result pertaining to first period prices

a probit model of choice dynamics there are many products which are repeatedly purchased by consumers in such cases it is likely that choice history that is the sequence of choices made in the past as well as marketing variables affect subsequent choice decisions attempts to model the effects of choice history have been generally based on the inclusion of variables that represent brand loyalty and or variety seeking behavior in this paper we present a model of dynamic choice behavior which is more general and incorporates four characteristics the first characteristic labeled preference reinforcement and preference reduction represents loyalty and variety seeking the second is the short term reluctance of a consumer to move from the current brand inertia or the willingness to move to another brand mobility the third characteristic captures the effect of repetitive consumption the long term effect on inertia and mobility the fourth characteristic incorporates the similarity or dissimilarity of choice alternatives this is important in a dynamic model because choice on the current purchase occasion can be affected by whether a similar or dissimilar alternative was chosen on the previous occasion similarities of alternatives are represented in terms of distances the effect of price on choice behavior is also modeled individual level purchase data from a consumer panel are used to estimate a covariance probit and an independent probit specification of the model from a substantive perspective the model gives interesting insights into the dynamics of choice behavior the model predicts switches better than a benchmark model which incorporates only loyalty in addition it is superior to three benchmark models in overall predictive ability

experimental comparisons of auctions under single and multi unit demand i introduction the study of multiple unit auctions is important because of their widespread use and the high value of goods sold examples include auctions of u s treasury debt cut flowers wine foreign exchange and other financial and monetary instruments moreover since auctions are often proposed by economists as a method of sale for other goods as in mcmillan 1994 the use of auctions can be expected to increase in the future many different auction rules are used to sell these diverse commodities and auction rule changes are often suggested usually with the intention of increasing revenue or improving the allocations and thus there is a considerable and increasing number of known auction formats evaluating new or comparing different auction mechanisms using field tests can be very costly and risky however experimental methods can and have been used by economists to study the behavioral characteristics of different auction procedures kagel 1995 provides a recent comprehensive survey most experimental studies consider the behavior of auctions when there is a single unit to be sold a few studies such as cox et al 1984 1985 and mccabe et al 1990 1991 study multiple unit auctions in environments in which each bidder demands at most one object from a set of identical objects being sold the studies of smith 1967 belovicz 1979 miller and plott 1985 and burns 1985 consider multi unit demand environments these are environments in which bidders have demand for multiple identical units and are permitted to purchase multiple units of the commodity sold the extension to multi unit demand is important since the presence of multi unit demand is a characteristic of many auctions in the field including all of the examples above in this study we consider the behavior of two types of multi unit auction under both single unit and multi unit demand we construct a laboratory environment which we use to study an english clock ec which is a special type of english auction and a sealed bid auction with lowest accepted bid pricing sb in the sb each bidder pays a per unit price equal to the lowest accepted bid the ec was chosen because it is known to provide highly efficient allocations in auctions of single unit goods and therefore is likely to be suggested for many field applications the sb was chosen because of its widespread use which makes its outcomes a useful basis of comparison for the outcomes of the english clock auction 1 however we do not attempt to represent a particular field situation here instead since our interest is in understanding the basic properties of the auctions we chose an experimental design that enables us to make simple comparisons across treatments and with previous and possibly future studies the design enables us to perform simple testing of game theoretic models in some of the treatments in our view the difference between single and multi unit demand is critical as we discuss in section ii many of the results of auction theory that are valid in single unit demand environments no longer apply in multi unit demand environments suggesting that the observed behavior of auctions might also differ between the two environments therefore we isolate the effects of multi unit demand by conducting single unit demand experiments under identical market demand and supply conditions as the multi unit demand experiments these and other aspects of the experimental design are described in detail in section iii the results and a discussion are given in sections iv and v respectively ii institutions theory and previous studies the english clock auction this variant of the english auction was modeled by milgrom and weber 1982 and studied by mccabe et al 1990 1991 in our version the auction begins with all bidders publicly and simultaneously announcing their initial quantity demanded at price zero if there is excess demand the price is increased by a small increment and the bidders then announce new quantities demanded

effects of price promotions on variety seeking and reinforcement behavior a stochastic model is proposed to examine how changes in frequency of price discounts affect brand choice decisions of consumers who exhibit variety seeking and reinforcement behavior it is shown that the effect on choice depends on whether the brand offering discounts is a major or minor brand in the product category this model extends the existing literature on stochastic models of variety seeking behavior by explicitly incorporating switching due to promotions along with intrinsic switching due to variety seeking the model yields testable hypotheses which are supported in a laboratory experiment and on analyses of the iri cracker data

a model of balanced choice behavior in some product categories consumers appear to alternate among items in a consistent and purposeful though not entirely deterministic fashion such alternation occurs even in the absence of any apparent external influences on choice to explain such balanced choice behavior we present a model based upon the premise that past consumption influences the utility of items on subsequent choice occasions individuals may seek variety on certain product attributes and exhibit loyalty toward others the model specification yields a logit choice model which may be calibrated using consumption diary panel data at the individual or cross sectional level