informational externalities and emergence of consensus we study a general model of dynamic games with purely informational externalities we prove that eventually all motives for experimentation disappear and provide the exact rate at which experimentation decays we also provide tight conditions under which players eventually reach a consensus these results imply extensions of many known results in the literature of social learning and getting to agreement

economics of leadership and hierarchy this paper explores leadership within hierarchical organizations for each hierarchy i consider a dynamic signaling game in which each player observes only the actions of his direct superiors before choosing his action at the top of the hierarchy are the leaders who learn the state from nature the hierarchy controls the flow of information and the timing of the game and determines the equilibrium output and welfare i show that the welfare optimal hierarchy is the chain because it maximizes the incentive of players to lead by example for their subordinates the chain remains optimal even in the presence of verifiable or unverifiable costly information acquisition by the leaders

the birth of a new market the authors consider a sequential decision model in which entrepreneurs decide on whether to enter a potential new market individual entrepreneurs have private expectations about the new market s viability over time they learn about its viability from their own experience as well as that of earlier entrepreneurs the distribution of the private expectations is said to be heterogeneous if external prior beliefs about the market s viability exist the authors show that heterogeneity of expectations cuts both ways while it facilitates the birth of viable markets it also generates via the existence of extremal beliefs excessive entry in nonviable markets copyright 1994 by royal economic society

nonlinear pricing to produce information we investigate the firm s dynamic nonlinear pricing problem when facing consumers whose tastes vary according to a scalar index we relax the standard assumption that the firm knows the distribution of this index in general the firm should determine its marginal price schedule as if it were myopic and produce information by lowering the price schedule bunching consumers at positive purchase levels should be avoided as a special case we also consider a market characterized by homogeneous consumers with a static but unknown demand curve we show that when there are repeat purchases the forward looking firm should tend towards penetration pricing otherwise its strategy should tend towards skimming we extend our insights to more general settings and discuss implications for pricing product lines

learning from others outcomes i develop a simple model of social learning in which players observe others outcomes but not their actions a continuum of players arrives continuously over time and each player chooses once and for all between a safe action which succeeds with known probability and a risky action which succeeds with fixed but unknown probability depending on the state of the world the actions also differ in their costs before choosing a player observes the outcomes of k earlier players there is always an equilibrium in which success is more likely in the good state and this alignment property holds whenever the initial generation of players is not well informed about the state in the case of an outcome improving innovation where the risky action may yield a higher probability of success players take the correct action as k in the case of a cost saving innovation where the risky action involves saving a cost but accepting a lower probability of success inefficiency persists as k in any aligned equilibrium whether inefficiency takes the form of under adoption or over adoption also depends on the nature of the innovation convergence of the population to equilibrium may be non monotone

self organising behaviour in the presence of negative externalities a conceptual model of commuter choice abstract we use a model with local interaction a one dimensional cellular automaton to study how commuters choose among alternative roads commuters have information about their neighbours most recent experience local interaction and they remember their own experiences memory we illustrate how a simple self organizing system based on local information and locally rational agents can in some cases outperform the nash equilibrium while the social optimum is unenforceable without a central planner due to the variations in individual travel times i e the social optimum is not individually rational variations across commuters in the steady state of our self organising system are at least equivalent to and mostly significantly larger than those required for the social equilibrium increasing the neighbourhood size illustrates that more information without co ordination leads to worse overall performance

regulatory fog the role of information in regulatory persistence abstract regulation is very persistent even when inefficient we propose an explanation for regulatory persistence based on regulatory fog the phenomenon by which regulation obscures information regarding the value of counterfactual policies we construct a dynamic model of regulation in which the underlying need for regulation varies stochastically and regulation undermines the social planner s ability to observe the state of the world compared to a full information benchmark regulation is highly persistent often lasting indefinitely regulatory fog is robust to a broad range of partially informative policies and can be quite detrimental to social welfare regulatory experiments modeled as costly and imperfect signals of the underlying state do not eliminate the effects of regulatory fog we characterize their effects and provide a framework for choosing amongst a set of potential regulatory experiments

dynamic agency with feedback a principal has a stochastically evolving target that he wishes an agent to repeatedly hit with his effort the agent does not obtain utility from hitting the target and therefore attempts to shirk the agent s utility is determined by a second process that symmetrically is of no use to the principal the principal cannot control effort or payoffs but can transmit signals to the agent who is relatively uninformed the principal s optimal signal may cause the agent s labor to be highly serially correlated this serial correlation has empirical relevance for the theory of managerial incentives and for the theory of business cycle fluctuations

learning and control in a changing economic environment abstract in this paper we investigate optimal bayesian learning and control with lagged dependent variables and time varying unknown parameters we assess both the performance of alternative decision rules as in the computationally oriented dual control literature as well as the dynamics of learning and convergence of beliefs as in the more theoretically oriented bayesian learning literature our numerical results indicate that the optimal decision rule involves a noticeable degree of experimentation for moderate to large levels of uncertainty in most situations though the optimal rule will remain less activist than a certainty equivalent rule and induce gradualism exceptions occur when the process to be controlled is near the deterministic steady state in this situation we find that the decision maker will repeatedly undertake costly experiments the extent of optimal experimentation is lower if the unknown parameter is perceived to vary over time in contrast to the fixed parameter case however parameter uncertainty is continually renewed and the incentive to experiment never ceases

simultaneously learning and optimizing using controlled variance pricing price experimentation is an important tool for firms to find the optimal selling price of their products it should be conducted properly since experimenting with selling prices can be costly a firm therefore needs to find a pricing policy that optimally balances between learning the optimal price and gaining revenue in this paper we propose such a pricing policy called controlled variance pricing cvp the key idea of the policy is to enhance the certainty equivalent pricing policy with a taboo interval around the average of previously chosen prices the width of the taboo interval shrinks at an appropriate rate as the amount of data gathered gets large this guarantees sufficient price dispersion for a large class of demand models we show that this procedure is strongly consistent which means that eventually the value of the optimal price will be learned and derive upper bounds on the regret which is the expected amount of money lost due to not using the optimal price numerical tests indicate that cvp performs well on different demand models and time scales this paper was accepted by assaf zeevi stochastic models and simulation

snobbery racism or mutual distaste what promotes and hinders cooperation in local public good provision a political jurisdiction may decide to cooperate in public schooling provision with its neighbors or remain independent the determinants of the consolidation decision are compared for the richer and the poorer and for the whiter and the less white jurisdiction in each potential consolidation pair property values and scale economies matter most however poorer jurisdictions prefer merging with richer ones that are less white than themselves whiter jurisdictions prefer to consolidate with less white ones of similar income less white jurisdictions are more open to consolidation with whiter ones if their incomes differ in either direction traditional club theory predictions are not supported

the implications of competition among jurisdictions does tiebout need politics the paper investigates whether compensation among local jurisdiction is by itself sufficient to ensure efficient provision of local public goods jurisdictions have fixed boundaries and each has an entrenched government with the power to tax and supply the public good residents can move costlessly among jurisdictions it is shown that competition among numerous jurisdictions is not sificient to guarantee public sector efficiency though residents can vote with their feet land is immobile hence governments can unsurp some land rents for their own ends increasing the number of jurisdictions limits but cannot completely eliminate the ability to exercise discretionary governmental power

learning in mis specified models and the possibility of cycles abstract i study the problem of a monopolist maximizing a sum of discounted profits facing a linear demand curve whose slope and intercept are unknown i show that if the monopolist has a mis specified model i e if the true slope and intercept lie outside of the support of the monopolist s prior beliefs then actions and beliefs may cycle on every sample path this behavior is shown to be robust to perturbations in the prior true parameter and actions such behavior is not possible if the agent s model is correctly specified instead actions and beliefs necessarily converge

price dispersion and incomplete learning in the long run abstract in each period a seller chooses a price and the customer for that period buys either one unit or nothing the relationship between price and purchase probability is one of two linear functions it is shown that the seller behaving optimally does not necessarily learn which function is the actual relationship since there can be a positive probability of sequences of prices converging to the price at which the two functions give the same purchase probability

a dynamic migration model with uncertainty we study a dynamic version of the harris todaro migration model where a finite population of infinitely lived bayesian agents choose consumption and migration decision rules as a function of their histories the agents do not know the production functions in the two sectors and learn about them through wage draws that they receive from the stochastic production functions the government knows the true production functions but is uninformed about the agents beliefs and the actual wage draws they observe the government maximizes its welfare function using wage subsidies in the two sectors and a migration tax we solve the agents dynamic programming problem and then use the solution to solve the government s dynamic programming problem we study the effects of government policies on the population distribution and illustrate the model by numerically solving a particular parametric example

experimentation and learning with networks effects abstract this paper considers learning in an competitive setting by allowing an opponent a head start unsuccessful unilateral experimentation may jeopardize future sales and profits we show that even in the absence of spillover and signalling effects competition can inhibit the scope of learning relative to a monopoly

corporate venturing and value creation a review and proposed framework abstract over the past decade companies worldwide have used corporate venturing cv as a means of revitalizing their operations building new capabilities and achieving strategic renewal creating value for shareholders business interest in cv has stimulated academic interest in the topic resulting in a rapidly growing but fragmented body of literature despite the growing international scholarly interest in cv researchers have devoted little effort to integrating prior findings in a cumulative fashion as a result studies do not build upon one another making it difficult to gauge the progress being made in addressing the fundamental research questions related to cv in this paper we examine the literature on cv seeking to synthesize integrate and link its key findings to do so we analyze this literature over the past decade to identify its major themes and research findings setting the stage for greater coherence in future research on cv we give special attention to the challenges and rewards of theory building in future cv research our review clearly shows that cv is an area of scholarly inquiry that has important implications for managerial practice

learning public good provision and the information trap abstract we consider an economy with uncertainty about the true production function for a public good by using bayes rule the economy can learn from experience we show that it may learn the truth but that it may also converge to an inefficient policy where no further inference is possible so that the economy is stuck in an information trap we also show that our results are robust with respect to small experimentation

information flows and social externalities in a tanzanian banana growing village this article analyses the role of social networks as facilitators of information flows and banana output increase based on a village census full information is available on the socio economic characteristics and banana production of farmers kinship group members neighbours and informal insurance group members the census data enable us to use individual specific reference groups and include exogenous group controls to tackle standard difficulties related to identification and omitted variables bias when analysing social effects for the survey village of nyakatoke in tanzania the results suggest that information flows exist within all types of groups analysed but output externalities are limited to kinship groups using networks may offer scope for effective information flows on agricultural techniques but our evidence suggests that not just any local network will have a social externality impact requiring a clear understanding of local social networks for maximum impact

learning about variable demand in the long run this paper studies the problem of a monopoly who is uncertain about the demand it faces and learns about it over time through its pricing experience the demand curve facing the monopoly is not constant it changes over time in a markovian fashion we characterize the monopoly s optimal policy and inquire how it differs from an informed monopoly s policy it turns out that even when the rate at which the demand varies is negligible the stationary probability with which the monopoly s policy deviates from its informed counterpart is nonnegligible as long as the discount factor is below 1

adoption of agricultural innovations in developing countries a survey this paper reviews various studies which have provided a description and possible explanation to patterns of innovation adoption in the agricultural sector the survey points out that the tendency of many studies to consider innovation adoption in dichotomous terms adoption nonadoption may not be appropriate in many cases where the actual decisions are defined over a more continuous range more attention needs to be given to the socio cultural and institutional environment in area studies so that their interrelation with economic factors affecting adoption can be inferred the presence of several interrelated innovations is another aspect that needs to be considered more carefully in future research since a number of simultaneous decisions may be involved furthermore the possibility of regular sequential patterns in adopting components of a new technological package should be specifically addressed in future studies finally the impact of differential adoption rates on land holding distribution merits attention in future research

on the surprising sufficiency of linear models for dynamic pricing with demand learning we consider a multiperiod single product pricing problem with an unknown demand curve the seller s objective is to adjust prices in each period so as to maximize cumulative expected revenues over a given finite time horizon in doing so the seller needs to resolve the tension between learning the unknown demand curve and maximizing earned revenues the main question that we investigate is the following how large of a revenue loss is incurred if the seller uses a simple parametric model that differs significantly i e is misspecified relative to the underlying demand curve we measure performance by analyzing the price trajectory induced by this misspecified model and quantifying the magnitude of revenue losses as a function of the time horizon relative to an oracle that knows the true underlying demand curve the price of misspecification is expected to be significant if the parametric model is overly restrictive somewhat surprisingly we show under reasonably general conditions that this need not be the case this paper was accepted by gerard cachon stochastic models and simulation

introduction to the stability of rational expectations equilibrium abstract this paper surveys the literature which examines the stability of the expectations that agents are assumed to have in a rational expectations equilibrium ree this issue is more complex than the usual statistical estimation problem because the relationship between observable variables and payoff relevant variables is endogenous one approach taken in the literature yields convergence to a ree but requires agents to have extensive knowledge about the structure and dynamics of the model that prevails while they learn a second approach does not assume that agents have correctly specified likelihood functions and finds that ree may not be stable

bargaining in a network of buyers and sellers abstract we analyze bargaining between buyers and sellers who are connected by an exogenously given network players can make repeated alternating public offers that may be accepted by any of the responders linked to each specific proposer our purpose is to find the conditions of the network which drive the price distribution in equilibrium this paper uses graph theory tools to provide necessary and sufficient conditions regarding the architecture of networks for the subgame perfect equilibrium of the bargaining game to coincide with the walrasian outcome

rational expectations equilibrium an alternative approach we study a dynamic market process in which traders condition their beliefs about payoff relevant parameters on past endogenously generated market data and current exogenous data we say that a market process is informative if the beliefs of traders who receive only endogenously generated market data converge almost surely to the true parameter value our main result is that under standard regularity hypotheses the generic market process is informative we define an equilibrium as the limit points of the market process journal of economic literature classification numbers 02 1 026 c 1984 academic press inc

the ignorant monopolist optimal learning with endogenous information economics lacks a good theory of the pricing and output decisions of a monopolist which does not know its demand we inevitably assume that the monopolist knows much more about demand conditions than is reasonable i present a model in which demand information is generated endogenously when information is endogenous the monopolist has an incentive to experiment with price and quantity i derive the direction of experimentation characterize an important value function arising from dynamic programming problems with learning and relate the results to blackwell s comparison of experiments copyright 1993 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

a dynamic oligopoly structural model for the prescription drug market after patent expiration this article incorporates consumer learning and heterogeneity into a dynamic oligopoly model for the prescription drug market in the model both firms and patients need to learn the generic qualities via patients experiences generic firms entry decisions are endogenous but their entry timings depend on a random approval process i apply the model to examine the impact of shortening the expected generic approval time although this policy experiment brings generics to the market sooner it increases a potential entrant s likelihood of entering a crowded market and hence could reduce the total number of generic entrants and consumer welfare

another look at the radner stiglitz nonconcavity in the value of information abstract this paper revisits the well known result of r radner and j stiglitz 1984 in bayesian models of economic theory elsevier amsterdam which shows that under certain conditions the value of information exhibits increasing marginal returns over some range their result assumes that both the number of states and the number of signal realizations are finite assumptions which preclude most analyses of optimal information acquisition we provide sufficient conditions that yield this nonconcavity in the value of information in a general framework the role that these conditions play is clarified and illustrated with several examples we also discuss the robustness of the nonconcavity result and the difficulties involved in getting the value of information to be globally concave journal of economic literature classification number d83

growth under uncertainty with experimentation abstract we introduce bayesian learning into a stochastic growth model and study the effect of experimentation on the optimal level of the investment decision and on the amount of information gathering when more investment produces more information experimentation can push towards a lower level of investment thus reducing information acquisition symmetrically when more investment reduces information experimentation can increase investment and again decrease information gathering these results run contrary to intuitions generated by the standard literature on experimentation

on industry life cycles delay entry and shakeout in beer brewing abstract this paper proposes a new explanation for industry shakeout an event evident in the life cycle of many industries in which the number of firms drops significantly in a short interval of time based on an in depth analysis of the shakeout in the united states beer brewing industry between 1880 and 1890 we propose that industry shakeouts naturally follow periods of mass entry by firms similar patterns are evident in two other industries we briefly examine the us automobile and tire industries while entry rates fluctuate broadly in all these industries we find that the timing of exit for a given cohort of entrants is remarkably similar over time the exit hazard rate is peaked in the first two years of every cohort s life and drops dramatically to low and stable levels for subsequent ages in this sense mass exit follows mass entry and does not require a deep explanation it is the mass entry evident in the data for these industries that requires an explanation we propose a theoretical model of information accumulation to explain entry into an industry entrepreneurs are uncertain about the profitability of the industry and this uncertainty is resolved through sufficient accumulation of information regarding the fortunes of incumbent firms delay in entry occurs solely due to the fact that it takes time to accumulate sufficient information to support more entry the resulting entry pattern from simulations of the model looks much like that observed in the industries we study

learning from neighbours when payoffs from different actions are unknown agents use their own past experience as well as the experience of their neighbours to guide their decision making in this paper we develop a general framework to study the relationship between the structure of these neighbourhoods and the process of social learning we show that in a connected society local learning ensures that all agents obtain the same payoffs in the long run thus if actions have different payoffs then all agents choose the same action and social conformism obtains we develop conditions on the distribution of prior beliefs the structure of neighbourhoods and the informativeness of actions under which this action is optimal in particular we identify a property of neighbourhood structures local independencewhich greatly facilitates social learning simulations of the model generate spatial and temporal patterns of adoption that are consistent with empirical work

the value of information in efficient risk sharing arrangements suppose that agents share risks in competitive markets we show that better information makes everyone worse off if the economy has a representative agent that is the economy s demand for state contingent consumption equals the demand of a hypothetical agent who owns all the economy s wealth the representative agent moreover is normatively unrepresentative although each agent dislikes information the representative agent is indifferent although we emphasize pure exchange our results imply that a representative agent model might seriously misstate the welfare effects of improved information in an economy with production and risk sharing even if it performs well otherwise

learning from others a welfare analysis abstract this paper considers a smooth and noisy version of the statistical prediction model studied in the herding informational cascades literature and compares market and optimal learning the latter is characterized by defining a decentralized welfare benchmark as the solution to an infinite horizon team problem market behavior involves herding in the sense that agents put too little weight on their private information for any given precision of public information and yields underinvestment in the production of public information however both market and optimal learning involve slow learning examples of the model include learning by doing reaching consensus and consumer learning about quality journal of economic literature classification numbers d82 d83

information asymmetry valuation and the corporate spin off decision we empirically analyze the information hypothesis that the separation of a rm s divisions into independently traded units through a spin o enhances value because it mitigates information asymmetry about the rm consistent with this hypothesis we nd that rms that engage in spin o s have higher levels of information asymmetry compared to their industry and size matched counterparts and the information problems decrease signi cantly after the spin o the gains around spin o s are positively related to the degree of information asymmetry and this relation is more pronounced for rms with fewer negative synergies between divisions finally rms with higher growth opportunities and rms in need of external capital show a higher propensity to engage in spin o s they also raise more capital following a spin o which is consistent with the view that

price dispersion and learning in a dynamic differentiated goods duopoly we study the evolution of prices set by duopolists who are uncertain about the perceived degree of product differentiation customers sometimes view the products as close substitutes sometimes as highly differentiated as the informativeness of the quantities sold increases with the price differential there is scope for active learning by firms when information has low value to the firms they charge the same price as would be set by myopic players and there is no price dispersion when firms value information more highly on the other hand they actively learn by creating price dispersion such price dispersion arises in a cyclical fashion and is most likely to be observed when the firms environment changes sufficiently often but not too frequently firms payoffs are higher when they use correlated pricing strategies contrary to what one might expect such coordination need not hurt consumers provided they are sufficiently impatient

bayesian economist bayesian agents i an alternative approach to optimal learning we generalize the results on bayesian learning based on the martingale convergence theorem to the sequential framework we show that the variability in the sequential framework is sufficient under mild conditions to circumvent the incomplete learning results that characterize the optimal learning literature we then give an alternative approach whereby the economist is bayesian with a prior on the space of agent priors we illustrate the usefulness of our approach by applying it to two popular economic examples a monopolist who does not know the demand curve he faces and the stochastic single sector growth model with an unknown production function

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

rules of thumb for social learning this paper studies agents who consider the experiences of their neighbors in deciding which of two technologies to use we analyze two learning environments one in which the same technology is optimal for all players and another in which each technology is better for some of them in both environments players use exogenously specified rules of thumb that ignore historical data but may incorporate a tendency to use the more popular technology in some cases these naive rules can lead to fairly efficient decisions in the long run but adjustment can be slow when a superior technology is first introduced

word of mouth communication and social learning this paper studies the way that word of mouth communication aggregates the information of individual agents we find that the structure of the communication process determines whether all agents end up making identical choices with less communication making this conformity more likely despite the players naive decision rules and the stochastic decision environment word of mouth communication may lead all players to adopt the action that is on average superior these socially efficient outcomes tend to occur when each agent samples only a few others i introduction economic agents must often make decisions without knowing the costs and benefits of the possible choices given the frequency with which such situations arise it is understandable that agents often choose not to perform studies or experiments but instead rely on whatever information they have obtained via casual word of mouth communication reliance on this sort of easily obtained information appears to be common in circumstances ranging from consumers choosing restaurants or auto mechanics to business managers evaluating alternative organizational structures this paper studies two related environments in arguing that individuals reliance on word of mouth communication has interesting implications for their aggregate behavior first motivated by the diffusion of new technologies we consider a choice between two competing products with unequal qualities or payoffs and show that the structure of communication is important in determining whether the population as a whole is likely to learn to use the superior product second we consider a choice between two products or practices that are equally good and ask whether consumers are likely to herd onto a single choice or whether diversity will obtain even in the long run we explore the implications of word of mouth communication in a simple nonstrategic environment there is a large population of identical players each of whom repeatedly chooses between two possible actions each player s payoff is determined by his own

from exogenous to endogenous economic networks internet applications economic agents behaviour is affected by their position in a network either exogenous or endogenous in which they interact with a sub set of neighbours only the network s links which may be generated by vertical and or horizontal relations or by more complex morphologies may explain the transition between dynamic equilibria and the instability of economic aggregates moreover networks shape strategic interaction among agents by determining their strategies the problem of access and interconnection particularly relevant in the internet is perhaps the best example a two way feedback between strategies and network structures arises instead when links are endogenous those features are clearly shown in the mechanism underlying the formation of peering links an dr d networks

a theory of public debt management with unobservable demand the literature on debt management has devoted little attention to the practice of floating debt using subscription issues i e at a fixed price and quantity even if this practice is rather common in many countries as an alternative to placement techniques that involve competitive bidding the focus of this paper is on this marketing strategy for a public debt manager facing uncertain market conditions in particular we consider a framework where government bonds are the only investment opportunity the debt manager therefore holds monopoly power over the market for financial assets and solves his profitmaximisation problem by setting the price of the bonds in the face of an unobservable demand function intertemporal economic decisions under uncertainty can be modelled as multiperiod control problems when the parameters of the true model are unknown as in our case a tradeoff typically arises between current profits and the value of information which can be extracted through price experimentation in an active learning framework in particular agents are assumed to use such information in order to update their stock of knowledge according to bayes rule 2 several applications of the modelling strategy discussed above have been explored for example an active learning setting can fit the description of the problem of a consumer facing the decision to buy a good with uncertain quality alternatively the same setting can be employed in order to investigate the behaviour of a monopolistic firm facing an unknown demand for its product in this paper we model the macroeconomic policy oriented issue previously illustrated as a stochastic multiperiod control problem with learning we therefore assume that debt policy and in particular the debt manager s pricing strategy is the result of the intertemporal maximisation of the government s objective function subject to a budget constraint in a context where information is optimally employed in the decision process in addition the

local fiscal competition an application to sales taxation with multiple federations abstract local sales tax rates influence the location of retail activity this paper develops a theory and empirical identification strategy for studying sales tax competition with multiple federations as exemplified by multiple counties each containing several cities in addition to strategic interactions with nearby cities and a city s own county city tax rates are influenced by the tax rates of neighboring counties cities react heterogeneously to own county sales tax rates depending on distance to the county border using data on the driving time to county borders and a comprehensive cross section of local sales tax rates i exploit variation in proximity to county borders to identify vertical fiscal competition cities located near county borders react more intensely to their county s tax rate in comparison to towns at the interior an increase in the neighboring county tax rate raises city tax rates in nearby counties

learning about the arrival of sales abstract we analyse optimal stopping when the economic environment changes because of learning a primary application is optimal selling of an asset when demand is uncertain the seller learns about the arrival rate of buyers as time passes without a sale the seller becomes more pessimistic about the arrival rate when the arrival of buyers is not observed the rate at which the seller revises her beliefs is affected by the price she sets learning leads to a higher posted price by the seller when the seller does observe the arrival of buyers she sets an even higher price

private monitoring in auctions abstract we study infinitely repeated first price auctions in which a bidder only learns whether or not he won the object while repetition of the stage game equilibrium is the unique nash equilibrium in public strategies with patient bidders there are simple nash equilibria in private strategies that improve on bid rotation sequential rationality is appropriately captured by essentially perfect bayesian equilibrium epbe which ignores behavior after irrelevant histories our main result is the construction of epbea that improve upon bid rotation assuming symmetry the exclusionary schemes of skrzypacz and hopenhayn tacit collusion in repeated auctions j econ theory 114 2004 153 169 including asymptotically efficient ones are supported as epbea

learning and strategic pricing we consider the situation where a single consumer buys a stream of goods from different sellers over time the true value of each seller s product to the buyer is initially unknown additional information can be gained only by experimentation for exogeneously given prices the buyer s problem is a multi armed bandit problem the innovation in this paper is to endogenize the cost of experimentation to the consumer by allowing for price competition between the sellers the role of prices is then to allocate intertemporally the costs and benefits of learning between buyers and sellers we examine how strategic aspects of the oligopoly model interact with the learning process all markov perfect equilibria mpe are efficient we identify an equilibrium which besides its unique robustness properties has a strikingly simple seemingly myopic pricing rule prices below marginal cost emerge naturally to sustain experimentation intertemporal exchange of the gains of learning is necessary to support efficient experimentation we analyze the asymptotic behavior of the equilibria

an empirical model of optimal dynamic product launch and exit under demand uncertainty this paper considers the decision problem of a firm that is uncertain about the demand and hence profitability of a new product we develop a model of a decision maker who sequentially learns about the true product profitability from observed product sales based on the current information the decision maker decides whether to scrap the product central to this decision problem are sequential information gathering and the option value of scrapping the product at any point in time the model predicts the optimal demand for information e g in the form of test marketing and it predicts how the launch or exit policy depends on the firm s demand uncertainty furthermore it predicts what fraction of newly developed products should be launched on average and what fraction of these products will fail i e exit the model is solved using numerical dynamic programming techniques we present an application of the model to the case of the u s ready to eat breakfast cereal industry simulations show that the value of reducing uncertainty can be large and that under higher uncertainty firms should strongly increase the fraction of all new product opportunities launched even if their point estimate of profits is negative alternative simpler decision rules are shown to lead to large profit losses compared to our method finally we find that the high observed exit rate in the u s ready to eat cereal industry is optimal and to be expected based on our model

bayesian dynamic pricing policies learning and earning under a binary prior distribution motivated by applications in financial services we consider a seller who offers prices sequentially to a stream of potential customers observing either success or failure in each sales attempt the parameters of the underlying demand model are initially unknown so each price decision involves a trade off between learning and earning attention is restricted to the simplest kind of model uncertainty where one of two demand models is known to apply and we focus initially on performance of the myopic bayesian policy mbp variants of which are commonly used in practice because learning is passive under the mbp that is learning only takes place as a by product of actions that have a different purpose it can lead to incomplete learning and poor profit performance however under one additional assumption a constrained variant of the myopic policy is shown to have the following strong theoretical virtue the expected performance gap relative to a clairvoyant who knows the underlying demand model is bounded by a constant as the number of sales attempts becomes large this paper was accepted by gerard p cachon stochastic models and simulation

a value function arising in the economics of information abstract the value function for a problem in the economics of the optimal accumulation of information is calculated as a fixed point of a contraction mapping by direct numerical iteration the optimal policy function is obtained as is the function defined as the sum of current expected reward and the discounted expected value of following the optimal policy in the future the optimal policy function is shown to be sensitive to the discount factor indeed for large values of the discount factor weighting the future heavily the policy function has a break and the value function is apparently not differentiable

leaving some stones unturned a reassessment of iterative planning theory abstract drawbacks of standard iterative planning algorithms include i planner actions are just on paper calculations without direct economic consequences and may converge very slowly ii planners cannot act systematically on hunches and intuitions and iii planners can observe unrealistically detailed information these problems are addressed through a bayesian learning model it is shown in sharp contrast to the standard literature that planners will not necessarily settle in the long run on even approximately optimal prices in an example the planner can end up setting prices in every period that guarantee chronic shortage this is an outcome of a fully optimizing model

escaping volatile inflation why has inflation been so stable in developed economies since the early 1990s in this paper we answer that the united states and other countries may have escaped from a volatile inflation equilibrium our argument builds on the story proposed by tom sargent in the conquest of american inflation where the fall in inflation in the 1980s was attributed to changing government beliefs to explain the escape in inflation volatility we unwind one of sargent s simplifications and allow the government to react to some of the shocks in the economy in this case when government beliefs turned against the phillips curve in the 1980s they not only led to an escape from high inflation but also stopped government using changes in inflation to offset shocks inflation and inflation volatility therefore escaped in tandem our analysis also sheds some light on why the escape in inflation occurred at the time it did

actively learning by pricing a model of an experimenting seller this article presents a model of a rational seller who is actively learning the slope of his demand curve via his pricing strategy consequently this seller optimally experiments with his price resulting price patterns show a tendency for discreteness as observed in the data which has proved to be a major challenge to most price setting models the experimentation motive can also replicate the observation that prices are more volatile than costs as well as the presence of many idiosyncratic price changes in the data it can do so without a need to assume the existence of large idiosyncratic shocks

a theory of learning with heterogeneous agents the authors study learning in organizations comprised of short lived agents with heterogeneous beliefs it is shown that the sequence of actions converges in probability to the set of ex post optimal actions under some identifiability conditions beliefs also converge in probability to point mass on the truth moreover while actions and posterior beliefs converge in probability they can simultaneously almost surely fail to converge the authors simulations of n kiefer s 1989 monopoly learning model suggest that if the firm is operated by a sequence of short lived managers with heterogeneous beliefs then complete learning of the demand curve obtains copyright 1995 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

combined pricing and inventory control under uncertainty this paper addresses the simultaneous determination of pricing and inventory replenishment strategies in the face of demand uncertainty more specifically we analyze the following single item periodic review model demands in consecutive periods are independent but their distributions depend on the item s price in accordance with general stochastic demand functions the price charged in any given period can be specified dynamically as a function of the state of the system a replenishment order may be placed at the beginning of some or all of the periods stockouts are fully backlogged we address both finite and infinite horizon models with the objective of maximizing total expected discounted profit or its time average value assuming that prices can either be adjusted arbitrarily upward or downward or that they can only be decreased we characterize the structure of an optimal combined pricing and inventory strategy for all of the above types of models we also develop an efficient value iteration method to compute these optimal strategies finally we report on an extensive numerical study that characterizes various qualitative properties of the optimal strategies and corresponding optimal profit values

searching for good policies policymaking is hard policymakers typically have imperfect information about which policies produce which outcomes and they are left with little choice but to fumble their way through the policy space via a trial and error process this raises a question at the heart of democracy do democratic systems identify good policies to answer this question i introduce a novel model of policymaking in complex environments i show that good policies are often but not always found and i identify the possibility of policymaking getting stuck at outcomes that are arbitrarily bad notably policy stickiness occurs in the model even in the absence of institutional constraints this raises the question of how institutions and the political environment impact experimentation and learning i show how a simple political friction uncertainty over voter preferences interacts with political competition and policy uncertainty in a subtle way that surprisingly improves the quality of policymaking over time

optimal experimentation in a changing environment this paper studies optimal experimentation by a monopolist who faces an unknown demand curve subject to random changes and who maximizes profits over an infinite horizon in continuous time we show that there are two qualitatively very different regimes determined by the discount rate and the intensities of demand curve switching and the dependence of the optimal policy on these parameters is discontinuous one regime is characterized by extreme experimentation and good tracking of the prevailing demand curve the other by moderate experimentation and poor tracking moreover in the latter regime the agent eventually becomes trapped into taking actions in a strict subset of the feasible set

bayesian learning in social networks we study the perfect bayesian equilibrium of a sequential learning model over a general social network each individual receives a signal about the underlying state of the world observes the past actions of a stochastically generated neighbourhood of individuals and chooses one of two possible actions the stochastic process generating the neighbourhoods defines the network topology we characterize pure strategy equilibria for arbitrary stochastic and deterministic social networks and characterize the conditions under which there will be asymptotic learning convergence in probability to the right action as the social network becomes large we show that when private beliefs are unbounded meaning that the implied likelihood ratios are unbounded there will be asymptotic learning as long as there is some minimal amount of expansion in observations we also characterize conditions under which there will be asymptotic learning when private beliefs are bounded

robustness and u s monetary policy experimentation we study how a concern for robustness modifies a policy maker s incentive to experiment a policy maker has a prior over two submodels of inflationunemployment dynamics one submodel implies an exploitable trade off the other does not bayes law gives the policy maker an incentive to experiment the policy maker fears that both submodels and his prior probability distribution over them are misspecified we compute decision rules that are robust to misspecifications of each submodel and of the prior distribution over submodels we compare robust rules to ones that cogley colacito and sargent 2007 computed assuming that the models and the prior distribution are correctly specified we explain how the policy maker s desires to protect against misspecifications of the submodels on the one hand and misspecifications of the prior over them on the other have different effects on the decision rule

the governance and control of voluntary corporate spin offs we investigate the role that a voluntary corporate restructuring can play in the design of efficient internal corporate control mechanisms to this end we examine the post restructuring internal control practices in 78 voluntary corporate spin offs that were completed between 1972 and 1987 we find that the selection of the new ceos the design of their compensation contracts and the staffing of the boards of directors and their compensation committees in the spun off firms can be seen as ex ante efficient these governance and control practices however are not strongly related to the observed positive market reactions to the spin off announcements the results indicate that equity reorganizations facilitate the implementation of efficient internal governance and control practices but that other factors must influence the share price reactions to the announcement of such voluntary corporate restructurings

experimentation with accumulation abstract we study signal dependent experimentation in the presence of accumulation and show that the passive learner s action surprisingly coincides with the experimentor s when the unknown term is the one determining the decay rate of the stock while they differ when the parameter being learned is the one measuring the accumulation rate these results highlight the importance of the dynamic structure of the problem in signal dependent experimentation moreover they have important consequences for the pollution accumulation debate currently in progress

the tiebout model bring back the entrepreneurs several recent papers in the literature have reformulltlated the nature of equilibrium in ifiebout mo lels by alssliuim ing an exogenous number of communities inflexible commullity l ou alaries anti in pirticular inactive lantlowners and developers ihis paper argues that these assumptions are unwarranted and resul1t iin in eterminate solutions and incorrect analyses determinate lon1g run1 solutions require equilibrium in intercommui land markets which in turn require giving lantlowners and or entrepreneurial leveloelers an active role in the models the role of politics in these models and its juxtaposition with entrepreneurial activities are also analyzed

benefits from u s monetary policy experimentation in the days of samuelson and solow and lucas a policy maker knows two models of ination unemplo yment dynamics one implies an exploitable trade o the other does not the policy maker s prior probability over the two models is part of his state vector bayes law converts the prior probability into a posterior probability at each date and gives the policy maker an incentive to experiment for two models calibrated to u s data through the early 1960s we isolate the component of government policy that is due to experimentation by comparing the outcomes from two bellman equations the rst of which experiments and learns the second of which learns but doesn t experiment we interpret the second as an anticipated utility model and study how well its outcomes approximate those from the experiment and learn bellman equation the approximation is good for our calibrations the benets from purposeful experimentation are small

searching and learning by trial and error i study a dynamic model of trial and error search in which agents do not have complete knowledge of how choices are mapped into outcomes agents learn about the mapping by observing the choices of earlier agents and the outcomes that are realized the key novelty is that the mapping is represented as the realized path of a brownian motion i characterize for this environment the optimal behavior each period as well as the trajectory of experimentation and learning through time applied to new product development the model shares features of the data with the well known product life cycle jel d81 d83 d92 l26

optimal growth with unobservable resources and learning abstract this paper examines the problem of choosing optimal resource consumption from an imperfectly observable aggregate capital wealth or resource stock which the decision maker learns about over time learning is complicated by the fact that the planner receives information about an object the true resource stock which is a moving target under the assumption that the utility of zero consumption is we show that the optimal policy follows a completely deterministic cautious or minmax policy that assumes the worst in each period and optimizes against that when this model is compared to a model with completely observable wealth levels the following insights are obtained 1 there is over saving 2 investment and output processes are more volatile than consumption and 3 regressions underestimate the risk aversion of agents information about the wealth or stock level is only valuable if it alters the support of the agent s beliefs thus information may be statistically informative yet economically valueless if information changes the support of the agent s beliefs then the optimal solution features an endogenous resource discovery process

leadership and the voluntary provision of public goods field evidence from bolivia abstract we conduct a controlled field experiment in 52 communities in rural bolivia to investigate the effect that local authorities have on voluntary public good provision in our study community members pool resources to provide environmental education material for local schools we find that voluntary contributions increase when democratically elected local authorities lead by example the results are driven by two factors 1 authorities like other individuals give more when they are called upon to lead than when they give in private and 2 high leader contributions increase the likelihood that others follow both effects are stronger when authorities as compared to randomly selected community members lead by example we explore two underlying sources of leadership influence first we provide evidence that the effect of a leader s contribution is not limited to signaling the value of the public good second we examine how leader characteristics affect the likelihood that others follow specifically our study shows that authority influence is driven by a combination of formal leadership status observable characteristics and the amount that authorities contribute when they give publicly before others

edge versus center finding common ground in the capitalization debate abstract a continuing debate questions whether capitalization of taxes and public services into house price occurs the current study argues for an inverse relationship between housing supply elasticity and capitalization rates a sample is split into houses on the interior and edge of the urban area capitalization of schooling and crime occurs everywhere but it is weaker toward the edge of an urban area where housing supply elasticities and developer activity are greater tax results are less robust but the capitalization rates of crime and school quality are roughly twice as strong on the interior than on the urban fringe

some stochastic processes of interdependent demand and technological diffusion of an innovation exhibiting externalities among adopters one frequently hears the opinion that as twentieth century society becomes more complex technological change assumes more significance and occurs at a more r apid pace investment in researclh and development results in a myriad of potential innovations yet as the frontiers of technology are plshed outward uncertainity about the usefulniess of innovations becomes an increasingly important factor in the decision whether or not to adopt the new innovation furthermore the decisions of individual economic agents tend to become increasingly interrelated many recent innovations are such that whether others adopt the device influences the benefits of adoption which accrue to a given consumer or firm such externalities may be positive for example consider a nation s decision to use the metric system the wearing of a style by a fashion leader a merchant s decision to accept a certain credit card or the purchase of a coinmunication device by someone with whom one desires to communicate or negative for instance imitation in the production of a faddish consumption item for which the potential market is limited or the pulrchase of a telephone by an obscene caller our goal is to analyze techn ological difflsioll with interdependencies when uncertainty and informational considerationis are an inherent part of the theoretical model the uncertainty may be of two types a technological ulncertainty the usefulness or quality of the innovation is at least partially unlknown and b adoption uncertainity incomplete or inaccurate knowledge about who is usinlg the innovation in our stochastic model adoptioni is reversible the decision to use the innovation is not permanent but rather agents may change their minds agents are not able to learn about the characteristics quality profitability usefulness etc of the innovation this assumption limits the applicability of

optimal jurisdictional fragmentation and mobility abstract tiebout s hypothesis is examined in a model with the continuum of income classes and no economies of scale of population in public output provision any efficient allocation of resources can be achieved in this model by a system of jurisdictions each containing a separate income class and each using a local property tax to finance local public output however in general at most one such allocation will be an equilibrium if residents can vote with their feet conditions are derived under which higher income residents will locate in jurisdictions providing a higher level of public output these are shown necessary given a separable utility function for any optimal allocation to be sustainable as an equilibrium when residents are mobile

credibility and strategic learning in networks we analyze a model of diffusion in a fixed finite connected network there is an interested party that knows the quality of the product being propagated and chooses an implant in the network to influence other agents to buy agents are either innovators who adopt immediately or rational rational consumers buy if buying instead of waiting maximizes expected utility we consider the conditions on the network under which optimal diffusion of the good product with probability 1 is a perfect bayes equilibrium

entry and vertical differentiation this paper analyzes the entry of new products into vertically differentiated markets where an entrant and an incumbent compete in quantities the value of the new product is initially uncertain and new information is generated through purchases in the market we derive the unique markov perfect equilibrium of the infinite horizon game under the strong long run average payoff criterion the qualitative features of the optimal entry strategy are shown to depend exclusively on the relative ranking of established and new products based on current beliefs superior products are launched relatively slowly and at high initial prices whereas substitutes for existing products are launched aggressively at low initial prices the robustness of these results with respect to different model specifications is discussed

strategic ignorance as a self disciplining device we analyse the decision of an agent with time inconsistent preferences to consume a good that exerts an externality on future welfare the extent of the externality is initially unknown but may be learned via a costless sampling procedure we show that when the agent cannot commit to future consumption and learning decisions incomplete learning may occur on a markov perfect equilibrium path of the resulting intra personal game in such a case each agent s incarnation stops learning for some values of the posterior distribution of beliefs and acts under self restricted information this conduct is interpreted as strategic ignorance all equilibria featuring this property strictly pareto dominate the complete learning equilibrium for any posterior distribution of beliefs

communication and coordination in social networks i model people in a coordination game who use a communication network to tell each other their willingness to participate the minimal sufficient networks for coordination can be interpreted as placing people into a hierarchy of social roles or stages initial adopters then followers and so on down to late adopters a communication network helps coordination in exactly two ways by informing each stage about earlier stages and by creating common knowledge within each stage we then consider two examples first we show that low dimensional networks can be better for coordination even though they have far fewer links than high dimensional networks second we show that wide dispersion of insurgents people predisposed toward participation can be good for coordination but too much dispersion can be bad although collective action depends on both social structure and individual incentives these integral aspects have been formalized separately in the fields of social network theory and game theory by considering them together this paper engages the classic question of which structures are conducive to coordination and shows that structure and strategy are related in a mutually interesting way here we consider a coordination game in which each person wants to participate only if others participate social structure is thought of as a communication network by which people tell each other their willingness to participate each person knows whether her neighbours in the network are willing but does not know about anyone else our model is thus a game of incomplete information in which each person given his local knowledge decides whether to participate the main result is a characterization of the minimal sufficient networks for coordination in terms of a hierarchy of social roles or stages initial adopters then followers and so on down to late adopters for example a communication network helps coordination in exactly two ways by informing each stage about earlier stages and by creating common knowledge within each stage we also consider two simple examples first we show that low dimension or strong link networks can be better for coordination even though they have far fewer links than high dimension or weak link networks second we show that wide dispersion of insurgents people predisposed toward participation can be good for coordination but too much dispersion can be bad this paper is built on the assumption that the most basic and common mechanism for coordination is the i ll go if you go mechanism individuals first communicate with each other about their preferences and then each individual chooses whether to participate or not hence a person s participation depends on what he knows about his neighbours it does not depend solely on their participation itself either through learning adaptation or social influence the physical analogies of contagion or diffusion are not

learning by doing and the value of optimal experimentation abstract recent research on learning by doing has provided the limit properties of beliefs and actions for a class of learning problems in which experimentation is an important aspect of optimal decision making however under these conditions the optimal policy cannot be derived analytically because bayesian learning about unknown parameters introduces a nonlinearity in the dynamic optimization problem this paper utilizes numerical methods to characterize the optimal policy function for a learning by doing problem that is general enough for practical economic applications the optimal policy is found to incorporate a substantial degree of experimentation under a wide range of initial beliefs about the unknown parameters dynamic simulations indicate that optimal experimentation dramatically improves the speed of learning and the stream of future payoffs furthermore these simulations reveal that a policy which separates control and estimation and does not incorporate experimentation frequently induces a long lasting bias in the control and target variables while these sequences tend to converge steadily under the optimal policy they frequently exhibit non stationary behavior when estimation and control are treated separately

industrial targeting experimentation and long run specialization abstract this paper emphasizes the experimental nature of industrial targeting policies under uncertainty in a small open economy a government promotes entry of new firms in selected industries and updates its beliefs about the country s comparative advantage in a bayesian way this selective targeting policy is analyzed in the framework of a special type of statistical decision problem known as the multi armed bandit the paper analyzes how the costs and benefits of learning about a country s comparative advantage depend on the characteristics of the targeted industries the framework suggests that even an optimally designed industrial targeting policy may eventually steer the country away from specializing according to its true comparative advantage

tiebout revisited redrawing jurisdictional boundaries abstract central city households who subsidize local public sector goods through local property taxes have an incentive to flee from the city or to change the jurisdiction s boundary we focus on the latter case a neighborhood s attempt to deannex from a central city and subsequently annex to a suburb the difficult theoretical problem is to explain why a large percentage of central city voters supported the deannexation proposal most apparently becoming worse off if the issue was approved while no explanation is consistent with fully rational voters it appears that high property value owning voters supported the attempt in hope of being part of the next wave of deannexers

learning from trades i study stationary cut off strategy equilibria of a dynamic market model where buyers sample sellers sequentially from an unknown distribution buyers learn about the distribution from the sampled sellers and a trade signal the trade signal reveals whether a randomly chosen seller traded yesterday observing a trade as opposed to no trade is good news about the distribution buyers who observe a trade use a higher cut off than buyers who observe no trade despite buyers learning from sampled sellers that puts a countervailing pressure on the cut offs the trade signal may reduce market efficiency while an appropriate exogenous signal increases efficiency