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

delays and equilibria with large and small information in social learning abstract the general model of social learning with irreversible investment and endogenous timing is analyzed for any distribution of private informations strategic complementarities and multiple equilibria appear which are generated solely by information externalities different equilibria generate strikingly different amounts of information the impacts of various assumptions bounded beliefs large number of agents discrete time and short periods are examined carefully the properties are robust to the introduction of observation noise with a continuum of agents

the impact of market structure and learning on the tradeoff between r d competition and cooperation this paper compares r d competition and cooperation when firms can devote resources to a safe investment or a risky r d investment when the discovery of a new product creates positive externalities on non discovering firms equilibrium investment flow ex ante investment and welfare under r d competition are less than or equal to what they are under research cooperation with negative externalities r d cooperation results in the same or lower ex ante investment than under r d competition and social welfare may also be less our results have relevance for empirical studies of the impact of r d cooperation on r d outcomes

the direction of innovation abstract how do innovation policies affect the direction of research is market based innovation too radical or too incremental we construct a novel and tractable model of the direction of innovation firms pursue inefficient research directions because they race to discover easy yet less valuable projects and because they work on difficult inventions where they can appropriate a larger portion of the social value fixing these inefficiencies requires policy to condition on properties of inventions that could have been discovered but were not policies which do not do so like patents and prizes may fail to encourage firms to research in the efficient direction even if they obtain the optimal quantity of r d

dynamic delegation of experimentation i study a dynamic relationship where a principal delegates experimentation to an agent experimentation is modeled as a one armed bandit that yields successes following a poisson process its unknown intensity is high or low the agent has private information his type being his prior belief that the intensity is high the agent values successes more than the principal does so prefers more experimentation the optimal mechanism is a cutoff rule in the belief space the cutoff gives pessimistic types total freedom but curtails optimistic types behavior pessimistic types over experiment while the most optimistic ones under experiment this delegation rule is time consistent

balanced bayesian mechanisms in the transferable utility case a number of authors have identified conditions on beliefs that guarantee the existence of bayesian incentive compatible mechanisms with balanced transfers we present a new easy to interpret condition and we show that it is strictly more general than all the other conditions found in the literature we also study conditions guaranteeing the bayesian implementability of all social decision rules with balanced budget mechanisms

the ex ante incentive compatible core in the absence of wealth effects in a differential information economy with quasi linear utilities monetary transfers facilitate the fulfillment of incentive compatibility constraints the associated ex ante core is generically non empty however we exhibit a wellbehaved exchange economy in which this core is empty even if goods are allocated through random mechanisms

learning and payoff externalities in an investment game abstract this paper examines the interplay of informational and payoff externalities in a two player irreversible investment game each player learns about the quality of his project by observing a private signal and the action of his opponent i characterize the unique symmetric equilibrium in a timing game that features a second mover advantage allowing for arbitrary correlation in project qualities despite private learning the game reduces to a stochastic war of attrition in contrast to the case of purely informational externalities all investments happen at the same real time instant irrespective of the sign of the correlation and beliefs never get trapped in a no learning region provided that the second mover advantage is sufficiently high

efficiency despite mutually payoff relevant private information the finite case individuals have or observe partly private information they independently choose acts possibly including messages the center may also act individuals utilities may depend on all acts and information including others private information are there incentives depending only on public information that make desired behavior a bayesian equilibrium assume incentive payments are separable and fully transferable appropriate incentives exisit either if the center s information depends stochastically however slightly on all relevant private information or if individuals relative valuations of acts however divergent are not too dissimilarly affected by different states of nature more generally one gives necessary and sufficient conditions for existence whenever the strategy profile asks agents to reveal all private knowledge relevant to their beliefs about the center s information

the scope of anonymous voluntary bargaining under asymmetric information we present a model of anonymous collective bargaining where individuals preferences and information may be significantly interdependent we show that the bargaining outcome becomes independent of individuals preferences and information as the bargaining group increases in size as a corollary we show that anonymous voluntary bargaining completely fails in large groups either the difference between the bargaining outcome and the status quo vanishes as the size of the group becomes larger or the bargaining becomes coercive and results in a violation of at least some individuals rights the result provides a rationale for the inherent difficulty of reform in the presence of asymmetric information

role of linking mechanisms in multitask agency with hidden information we investigate the adverse selection problem where a principal delegates multiple tasks to an agent we characterize the virtually implementable social choice functions by using the linking mechanism proposed by jackson and sonnenschein 2007 that restricts the message spaces the principal does not require any incentive wage schemes and can therefore avoid any information rent and welfare loss we show the resemblance between the functioning of this message space restriction and that of incentive wage schemes we also extend the results of the single agent model to the multi agent model

negatively correlated bandits we analyse a two player game of strategic experimentation with two armed bandits either player has to decide in continuous time whether to use a safe arm with a known pay off or a risky arm whose expected pay off per unit of time is initially unknown this pay off can be high or low and is negatively correlated across players we characterize the set of all markov perfect equilibria in the benchmark case where the risky arms are known to be of opposite type and construct equilibria in cut off strategies for arbitrary negative correlation all strategies and pay offs are in closed form in marked contrast to the case where both risky arms are of the same type there always exists an equilibrium in cut off strategies and there always exists an equilibrium exhibiting efficient long run patterns of learning these results extend to a three player game with common knowledge that exactly one risky arm is of the high pay off type

correlated types and bayesian incentive compatible mechanisms with budget balance abstract this note presents a condition which guarantees the existence of a bayesian incentive compatible mechanism with budget balance when agents have quasi linear utility functions this condition requires correlation among agents private signals types and is 1 simple and easy to verify 2 good for any decision rule whether efficient or not 3 valid even if agents types are mutually payoff relevant and 4 true for almost every probability distribution of agents types journal of economic literatureclassification numbers c72 d82

alarmist decisions with divergent risk information receipt of multiple sources of risk information ideally should foster sounder decisions under uncertainty this paper s original survey results for environmental risks suggest that the learning process is reasonable in many respects bur it does not accord with a rational bayesian learning model divergent risk assessments from different sources produce extreme violations of rationality as there is inordinate weight on the high risk assessment this alarmist reaction holds for both government and industry information sources this phenomenon may account for the commonly observed phenomenon of public overreaction to highly publicised risks

linear inequality methods to enforce partnerships under uncertainty an overview we review different generic conditions on stochastic outcome functions to enforce either efficient or nearly efficient partnerships their logical relationship is explored two kinds of conditions are considered however the property for an action profile to be compatible plays a crucial role in both kinds also two kinds of enforcement mechanisms are considered enforcement through utility transfers and enforcement through repetition

optimal entry timing abstract a player of privately known strength chooses when to enter a market and an incumbent chooses whether to compete or concede information about the potential entrant s type is revealed publicly according to an exogenous news process and the timing of entry i analyze stationary equilibria using the public belief as a state variable no equilibria in pure strategies exist and smooth pasting conditions need not hold under both d1 and a novel refinement the informed player has nondecreasing value functions and her strategy has the following structure for high states both types enter with certainty for a possibly empty interval of intermediate states no type enters and for low states the high type enters while the low type mixes i obtain closed form solutions and analyze comparative statics for such equilibria the welfare effects of the presence of news relative to no news depend on the starting belief however for a fixed equilibrium a marginal increase in news quality always helps the informed player regardless of her type and always hurts total welfare

strategic merger waves a theory of musical chairs this paper proposes an explanation of merger waves based on the interaction between competitive pressure and irreversibility of mergers in an uncertain environment a set of acquirers compete over time for scarce targets at each point in time an acquirer can either postpone a takeover attempt or raid immediately by postponing the takeover attempt an acquirer may gain from more favorable future market conditions but runs the risk of being preempted by rivals first a complete information model is considered and it is shown that the above tradeoff leads to a continuum of subgame perfect equilibria in monotone strategies that are strictly pareto ranked all these equilibria share the feature that all acquirers rush simultaneously in merger waves the model is then extended to a dynamic global game by introducing slightly noisy private information about merger profitability this game is shown to have a unique markov perfect bayesian equilibrium in monotone strategies and the timing of the merger wave can thus be predicted last the comparative dynamics predictions of the model are related to stylized facts

investment timing and learning externalities abstract we study a duopoly model of investment in which each player learns about the quality of a common value project by observing some public background information and possibly the experience of his rival investment costs are private information and the background signal takes the form of a poisson process conditional on the quality of the project being low the resulting attrition game has a unique symmetric equilibrium which depends on initial public beliefs we determine the impact of changes in the cost and signal distributions on investment timing and how equilibrium is affected when a first mover advantage is introduced

subgame perfect implementation under information perturbations we consider the robustness of extensive form mechanisms to deviations from common knowledge about the state of nature which we refer to as information perturbations first we show that even under arbitrarily small information perturbations the moore repullo mechanism does not yield even approximately truthful revelation and that in addition the mechanism has sequential equilibria with undesirable outcomes more generally we prove that any extensive form mechanism is fragile in the sense that if a non maskin monotonic social objective can be implemented with this mechanism then there are arbitrarily small information perturbations under which an undesirable sequential equilibrium also exists finally we argue that outside options can help improve efficiency in asymmetric information environments and that these options can be thought of as reflecting ownership of an asset

the impact of inflation on the real income of u s farmers according to conventional economic theory an unanticipated increase in the rate of general price inflation benefits those whose money incomes are flexible at the expense of those whose money incomes are fixed farmers have flexible money incomes hence theory suggests that farmers should benefit from an unanticipated increase in the rate of inflation yet at least for recent time periods empirical studies have not found that farmers gain real income as a result of an increase in the rate of general price inflation for example tweeten concluded that the terms of trade for farmers deteriorates improves as the rate of inflation rises falls this conclusion was based on his empirical finding that as inflation increases prices paid by farmers increase faster than the prices they receive on the other hand studies by gardner prentice and schertz and chambers found no significant effects of inflation on farmers terms of trade in this paper we examine various measures of relative prices over different time periods to test the hypothesis suggested by economic theory that farmers are benefitted by an acceleration in the rate of general price inflation and conversely are harmed by a deceleration in the inflation rate the real income of farmers is equal to the sum of the physical quantities which they produce multiplied by the money prices they receive all then divided by the general price level here we ignore changes in the physical production of farmers and concentrate on the behavior of the prices they receive for this physical production relative to the behavior of other prices we assume that if the prices farmers receive for their physical production rise fall relative to other prices the economic well being of farmers is enhanced diminished

the relevance of private information in mechanism design abstract recent results in mechanism design show that as long as agents have correlated private information and are sufficiently risk neutral it is possible to design mechanisms that leave agents with arbitrarily small information rents we show that these full rent extraction results hinge on the implicit assumption that the agents beliefs uniquely determine their preferences we present an example of the voluntary provision of a public good in which this assumption is relaxed and consequently even in highly correlated environments if agents beliefs do not uniquely determine their preferences then the extraction of the agents entire information rents is impossible

rational frenzies and crashes most markets clear through a sequence of sales rather than through a walrasian auctioneer because buyers can decide whether to buy now or later rather than only now or never their current willingness to pay is much more sensitive to price than the demand curve is a consequence is that markets will be extremely sensitive to new information leading to both frenzies in which demand feeds on itself and crashes in which price drops discontinuously the paper also shows how a result from static auction theory the revenue equivalence theorem can be applied to solve for a dynamic price path

business as usual market crashes and wisdom after the fact the authors present a three stage model of market dynamics in the first stage routine behavior tends to keep information of common interest trapped in private hands in the second stage private information reaches a threshold that triggers some agents to alter their behavior these actions release information to the market the final stage involves the market s response to this news as other participants react to the initial departure from routine behavior the authors present an application to industry investment they also outline applications to the international debt crisis to bank runs and to political upheavals copyright 1994 by american economic association

learning and information aggregation in an exit game we analyze information aggregation in a stopping game with uncertain common payos players learn from their own private experiences as well as by observing the actions of other players we give a full characterization of the symmetric mixed strategy equilibrium and show that information aggregates in randomly occurring exit waves observational learning induces the players to stay in the game longer the equilibria display aggregate randomness even for large numbers of players

eliciting informative feedback the peer prediction method many recommendation and decision processes depend on eliciting evaluations of opportunities products and vendors a scoring system is devised that induces honest reporting of feedback each rater merely reports a signal and the system applies proper scoring rules to the implied posterior beliefs about another rater s report honest reporting proves to be a nash equilibrium the scoring schemes can be scaled to induce appropriate effort by raters and can be extended to handle sequential interaction and continuous signals we also address a number of practical implementation issues that arise in settings such as academic reviewing and online recommender and reputation systems

information revelation and strategic delay in a model of investment we model investment as an n player game with a pure informational externality each player s payoff depends only on his own action and the state of nature however because a player s action reveals his private information players wait to see what other players will do equilibrium is inefficient because delay is costly and information is imperfectly revealed we characterize the unique symmetric perfect bayesian equilibrium and study the robustness of delay which turns out to be sensitive to the reaction speed and the number of players we establish the following results i when the period length is very short the game ends very quickly and there is a form of herding or informational cascade which results in a collapse of investment ii as the period length increases the possibility of herding disappears iii as the number of players increases the rate of investment and the information flow are eventually independent of the number of players adding more players simply increases the number who delay iv in the limit the time profile of investment is extreme a period of low investment followed either by an investment surge or a collapse

preemption games under levy uncertainty abstract we study a stochastic version of fudenberg tirole s preemption game two firms contemplate entering a new market with stochastic demand firms differ in sunk costs of entry if the demand process has no upward jumps the low cost firm enters first and the high cost firm follows if leader s optimization problem has an interior solution the leader enters at the optimal threshold of a monopolist otherwise the leader enters earlier than the monopolist if the demand admits positive jumps then the optimal entry threshold of the leader can be lower than the monopolist s threshold even if the solution is interior simultaneous entry can happen either as an equilibrium or a coordination failure the high cost firm can become the leader we characterize subgame perfect equilibrium strategies in terms of stopping times and value functions analytical expressions for the value functions and thresholds that define stopping times are derived

decomposing uncertainty and its effects on imitation in firm exit decisions this study examines the effects of different uncertainty types on interorganizational imitation in firm exit decisions we draw on herding models to conceptualize exit decisions as being based on a firm s private information which the firm updates with information inferred from observing the actions of others we posit that different types of uncertainty differentially affect this observational learning process in particular we propose that certain uncertainty types attenuate rather than foster observational learning and subsequent imitation we test this theory using a 29 year panel data set on the exit of private venture capital firms our results indicate that observational learning does influence imitation in firm exit decisions and they also suggest that a common belief that uncertainty enhances imitation does not apply to all types of uncertainty specifically we find that uncertainty fosters imitation only when it is idiosyncratic to the firm uncertainties that are common to all firms in contrast actually reduce reliance on observational learning by decomposing uncertainty into different types and explicating their effects on imitation we demonstrate that this relationship is more nuanced than previously assumed and in addition highlight the role of deliberate information processing in imitation

maintaining a reputation when strategies are imperfectly observed this paper studies reputation effects in games with a single long run player whose choice of stage game strategy is imperfectly observed by his opponents we obtain lower and upper bounds on the long run player s payoff in any nash equilibrium of the game if the long run player s stage game strategy is statistically identified by the observed outcomes then for generic payoffs the upper and lower bounds both converge as the discount factor tends to 1 to the long run player s stackelberg payoff which is the most he could obtain by publicly committing himself to any strategy

strategic learning in teams this paper analyzes a two player game of strategic experimentation with three armed exponential bandits in continuous time players face replica bandits with one arm that is safe in that it generates a known payoff whereas the likelihood of the risky arms yielding a positive payoff is initially unknown it is common knowledge that the types of the two risky arms are perfectly negatively correlated i show that the efficient policy is incentive compatible if and only if the stakes are high enough moreover learning will be complete in any markov perfect equilibrium with continuous value functions if and only if the stakes exceed a certain threshold

information rigidities and asymmetric business cycles abstract we study the link between asymmetries of markups and firm exit rates and asymmetries in information acquisition along the u s business cycle we argue that a model of optimal firm exit under rational inattention produces lagged counter cyclical and positively skewed markups together with counter cyclical exit rates consistent with the empirical evidence our model also predicts counter cyclical information rigidities consistent with survey evidence

delay and information aggregation in stopping games with private information abstract we consider equilibrium timing decisions in a model with a large number of players and informational externalities the players have private information about a common payoff parameter that determines the optimal time to invest they learn from each other in real time by observing past investment decisions we develop new methods of analysis for such large games and we give a full characterization of symmetric equilibria we show that the equilibrium statistical inferences are based on an exponential learning model although the beliefs converge to truth learning takes place too late ex ante welfare is strictly between that without observational learning and that with full information

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