earnings and ratings at google answers i introduction most research on internet transactions considers online markets as forums to facilitate the sale of physical goods ellison and fisher ellison 2009 goolsbee and chevalier 2003 sometimes the internet is analyzed as a market for matching workers and firms for an ordinary real world employment relationship kuhn 2004 but certain web sites can also supplement or even replace in person employment relationships this is the approach at google answers a web based service that facilitates paid matches between answerers who have answers or research skills and askers who offer payment for answers to their respective questions i analyze all questions and answers from the inception of the google answers service through november 2003 and i find notable trends in answerer behavior more experienced answerers provide answers with the characteristics askers most value receiving higher ratings as a result answerer earnings increases in experience consistent with learning on the job answerers who focus on particular question categories provide answers of higher quality but earn lower pay per hour perhaps reflecting a lack of versatility answers provided during the business day receive higher payments per hour a compensating differential for working when outside options are most attractive but more experienced answerers tend to forego these opportunities ii literature and context google answers is distinctive in that its entire service and entire employment relationship occur online in contrast most online sales processes anticipate offline functions such as packing and sending merchandise in some respects this online only environment eases analysis a researcher may see the answerer s entire service letting the researcher fully assess quality in contrast an ebay seller s quality generally is unobservable or only partially observer to a researcher nonetheless google answers does not provide all data researchers might seek for example although google answers receives answerers resumes and geographic locations as part of the application process google answers does not share this data with the general public chen ho and kim 2008 address these constraints through field experiments that pay google answers answerers to address questions posed by the authors allowing measurement of the effects of varying prices and gratuities parameters on answerers responses beyond chen ho and kim others have also examined google answers rafaeli raban and ravid 2005 present summary statistics of 2002 2004 answers regner 2005 finds that social preferences and reputation influence askers choice to provide optional gratuities to answerers adamic et al 2008 study answer quality and reputation at the competing though unpaid service yahoo answers iii methodology and data set all data for my analysis comes from the google answers web site http answers google com as it stood in november 2003 i wrote software to extract questions answers and profiles from the answers site forming a database of more than 40 000 questions and answers with only a few exceptions 1 i observe all google answers questions and answers posted through november 2003 2 for each question asked i observe the question itself text and title the question s categorization within google answers taxonomy the time at which the question was asked the payment amount offered by asker to answerer and the asker s username for answered questions i observe the time at which the question was answered the answer including length in characters and number of included urls and the answerer s username when the asker rated the answer i observe the rating when the asker offered a gratuity to the answerer i observe the amount of the gratuity google answers allows an answerer to lock a question obtaining the temporary exclusive fight to answer it for the following 4 8 hours depending on question price

communication networks knowledge and decisions that communication pervades the everyday life of organizations is a statement of the obvious how this widespread communication affects organization s performance is less clear another truism about organizations is that their members are seldom fully knowledgeable of the exact state of the world in which they operate to overcome this information uncertainty burden organizations tend to devote a substantial amount of resources to retrieve information about their environment individual experimentation is a natural way to obtain superior information when the nature and the consequences of the prevailing uncertainty is common to all organization members a natural substitute for replications of individual experiments is to have agents communicate their private information among themselves communication is then a means to save on experimentation costs when they display diminishing returns in another vein shared information fosters coordination between individual agents which is beneficial to the organization as a whole when coordinated actions lead to higher benefits for everyone altogether when each organization member individually ascertains that both uncertainty and coordination are the main driving networked interactions

aggregation of information in large cournot markets consider a homogeneous product market where firms have private information about an uncertain demand parameter and compete in quantities we examine the convergence properties of bayesian cournot equilibria as the economy is replicated and conclude that large cournot or almost competitive markets do not aggregate information efficiently except possibly when the production technology exhibits constant returns to scale even in a competitive market there is a welfare loss with respect to the first best outcome due to incomplete information in general nevertheless a competitive market is efficient taking as given the decentralized private information structure of the economy endogenous and costly information acquisition is examined and seen to imply that the market outcome always falls short of the first best level with decreasing returns to scale the results are also shown to be robust to the addition of extra rounds of competition which allows firms to use the information revealed by past prices explicit closed form solutions yielding comparative static results are obtained for models characterized by quadratic payoffs and affine information structures

computing multi period information constrained optima this paper presents a detailed theoretical derivation and justification for methods used to compute solutions to a multi period including infinite period continuum agent unobservedeffort economy actual solutions are displayed illustrating cross sectional variability in consumption and labour effort in the population at a point in time and variability for a typical individual over time the optimal tradeoff between insurance and incentives is explored and the issue of excess variability is addressed by consideration of the analogue full information economy and various restricted contracting regimes

a recursive formulation for repeated agency with history dependence abstract we present general recursive methods to handle environments where privately observed variables are linked over time we show that incentive compatible contracts are implemented recursively with a threat keeping constraint in addition to the usual temporary incentive compatibility and promise keeping conditions journal of economic literature classification numbers d30 d31 d80 d82

information use and acquisition in price setting oligopolies asymmetric price setting multi product suppliers have access to multiple sources of information about demand conditions where the publicity of each source corresponds to the cross industry correlation of signals received from it a signal s influence on suppliers prices is increasing in its publicity as well as in its precision the emphasis on relatively public information is stronger for smaller suppliers who control narrower product portfolios when information is endogenously acquired suppliers listen to only a subset of information sources this subset is smaller when products are less differentiated and when the industry is less concentrated smaller suppliers focus attention on fewer information sources the inefficiencies arising from information acquisition and use are identified the associated externalities depend upon the extent of product differentiation the concentration of the industry and the degree of decreasing returns to scale

knowing what others know coordination motives in information acquisition we explore how optimal information choices change the predictions of strategic models when a large number of agents play a game with strategic complementarity information choices exhibit complementarity as well if an agent wants to do what others do they want to know what others know this makes heterogeneous beliefs di cult to sustain and may generate multiple equilibria in models with substitutability agents prefer to difierentiate their information choices we use these theoretical results to examine the role of information choice in recent price setting models and to propose modeling techniques that ensure equilibrium uniqueness

multi period contracts between principal and agent with adverse selection abstract multi period contracts with adverse selection at the time of contracting are studied with risk neutrality and independent private information all inefficiency arises in the first period only with positive serial correlation inefficiency is more pervasive but declines over time

social preferences google answers abstract we analyse pricing effort and tipping decisions at the online service google answers users set a price for the answer to their question ex ante and they can additionally tip the researcher who provided the answer ex post a positive wage effort relationship is frequently found in laboratory gift exchange games yet field evidence for reciprocity in two stage settings wage effort is mixed our field data confirms lab findings for the three stage design wage effort bonus tipping is motivated by reciprocity but also by reputation concerns among frequent users moreover researchers seem to adjust their effort based on the user s previous tipping behaviour an efficient sorting takes place when sufficient tip history is available in addition we analyse how tipping is adopted when the behavioural default is not to tip and suggest estimates for reciprocal and selfish strategic and myopic user types

strategic communication networks in this paper we consider situations in which individuals want to choose an action close to others actions as well as close to a payoff relevant state of nature with the ideal proximity to the common state varying across the agents before this coordination game with heterogeneous preferences is played a cheap talk communication stage is offered to players who decide to whom they reveal the private information they hold about the state the strategic information transmission taking place in the communication stage is characterized by a strategic communication network we provide a direct link between players preferences and the strategic communication network emerging at equilibrium depending on the strength of the coordination motive and the prior information structure equilibrium strategic communication networks are characterized in a very tractable way and compared in term of efficiency in general a maximal strategic communication network may not exist and communication networks cannot be ordered in the sense of pareto however expected social welfare always increases when the communication network expands strategic information transmission can be improved when group or public communication is allowed and or when information is certifiable

optimal research for cournot oligopolists we extend the classical cournot model to take account of uncertainty in either the cost function or the demand function by undertaking research firms can acquire private asymmetric information to help resolve their uncertainty and make a more informed production decision the model is a two stage game in the first stage research levels are chosen and in the second stage conditional on private research outcomes production decisions are made we find that for a linear continuous information structure there is a unique nash equilibrium to the game in the equilibrium there may be an inefficient amount of aggregate research and there may be incomplete pooling as well the model specializes to the classical case when the cost of research is zero and each firm gains essentially the same information by doing an infinite amount of research or when the cost of research is so high no firm undertakes research

incentives and aggregate shocks this paper presents an incentive based theory of the dynamics of the distribution of consumption in the presence of aggregate shocks the paper builds on the models concerning the distribution of income or consumption and incentive problems of green 1987 thomas and worrall 1991 phelan and townsend 1991 and atkeson and lucas 1992 by incorporating aggregate production shocks the model allows an examination of the interactions between individual and aggregate consumption series given incomplete insurance further the methodology outlined allows the incorporation of incentive considerations to macroeconomic environments similar to rogerson 1988 and hansen 1985

information acquisition and welfare we study information acquisition in a flexible framework with strategic complementarity or substitutability in actions and a rich set of externalities that are responsible for possible wedges between the equilibrium and the efficient acquisition of information first we relate the in efficiency in the acquisition of information to the in efficiency in the use of information and explain why efficiency in the use is no guarantee of efficiency in the acquisition next we show how the acquisition of private information affects the social value of public information i e the comparative statics of equilibrium welfare with respect to the quality of public information finally we illustrate the implications of the results in a monetary economy with price rigidities and dispersed information about productivity shocks

cournot competition and the social value of information in a differentiated product cournot model each supplier receives informative signals about demand the cross industry correlations of the signals differ more public signals have higher correlation coefficients in equilibrium information is used inefficiently from the industry s perspective information is over used and too much emphasis is placed on relatively public signals from the consumer s perspective information is under used and too much emphasis is placed on relatively private signals welfare is enhanced by increasing the use of information as desired by consumers but re balancing that use away from public signals as desired by the industry if information is costly and endogenously acquired then suppliers acquire too much new information but they use it too little

information acquisition and welfare in network games abstract this paper studies information acquisition and use in network games the network structure incorporates both strategic complements positive links and substitutes negative links an information use game played on a correlation adjusted network is derived equilibrium inefficiencies in both acquisition and use of information are characterized inefficient bunching obtains in information acquisition where the spread in equilibrium signal precisions is below that prescribed by the planner the welfare analysis offers a policy intervention publicizing players information investments the more linked a player is positively or negatively the more strongly they respond to the policy to influence others information acquisition and use

optimal unemployment insurance this paper considers the design of an optimal unemployment insurance system the problem is modeled as a repeated principalagent problem involving a risk averse agent the unemployed worker and a risk neutral principal which cannot monitor the agent s search effort the optimal long term contract subject to the associated incentive constraints is characterized this contract involves a replacement ratio that decreases throughout the unemployment spell and a wage tax after reemployment that under some mild regularity conditions increases with the lenght of the unemployment spell some numerical results are presented that suggest that the gains from switching to this optimal unemployment insurance scheme could be quite large the performance of this optimal contract is also compared to alternative liquidity provision mechanisms

on efficient distribution with private information this paper is a study of the dynamics of the efficient distribution of consumption in an exchange economy with many consumers each of whom is subject to private idiosyncratic taste shocks we propose a recursive method for finding feasible allocations that are incentivecompatible and that are pareto optimal within this set the method is applied to several parametric examples we find that in an efficient allocation the degree of inequality continually increases with a diminishing fraction of the population receiving an increasing fraction of the resources we discuss the extent to which these allocations can be decentralized via market arrangements this paper is a study of the dynamics of the efficient distribution of consumption in an exchange economy with private information the economy we study has a constant endowment flow of a single non storable consumption good which is to be allocated each period among a large number of consumers each period these consumers experience unpredictable idiosyncratic privately observed taste shocks affecting their marginal utility of current consumption efficiency dictates that more resources be allocated to those consumers who in any given period have a high marginal utility of current consumption

efficient use of information and social value of information this paper analyzes equilibrium and welfare for a tractable class of economies games that have externalities strategic complementarity or substitutability and heterogeneous information first we characterize the equilibrium use of information complementarity heightens the sensitivity of equilibrium actions to public information raising aggregate volatility whereas substitutability heightens the sensitivity to private information raising cross sectional dispersion next we define and characterize an efficiency benchmark designed to address whether the equilibrium use of information is optimal from a social perspective the efficient use of information reflects the social value of aligning choices across agents finally we examine the comparative statics of equilibrium welfare with respect to the information structure the social value of information is best understood by classifying economies according to the inefficiency if any in the equilibrium use of information we conclude with a few applications including production externalities beauty contests business cycles and large cournot and bertrand games

the effects of social networks on employment and inequality we develop a model where agents obtain information about job opportunities through an explicitly modeled network of social contacts we show that employment is positively correlated across time and agents moreover unemployment exhibits duration dependence the probability of obtaining a job decreases in the length of time that an agent has been unemployed finally we examine inequality between two groups if staying in the labor market is costly and one group starts with a worse employment status then that group s drop out rate will be higher and their employment prospects will be persistently below that of the other group

internet job search and unemployment durations after decades of stability the technologies used by workers to locate new jobs began to change rapidly with the diffusion of internet access in the late 1990 s which types of persons incorporated the internet into their job search strategy and did searching for work on line help these workers find new jobs faster we address these questions using measures of internet job search derived from the december 1998 and august 2000 cps computer and internet supplements matched with job search outcomes from subsequent cps files we find that internet searchers are positively selected on observables but negatively selected on unobservables a beneficial unemployment duration reducing causal effect of internet job search is consistent with our estimates only if negative selection on unobservables is especially strong in other words only if the population of on line resumes is strongly adversely selected

collusion with persistent cost shocks we consider a dynamic bertrand game in which prices are publicly observed and each firm receives a privately observed cost shock in each period although cost shocks are independent across firms within a firm costs follow a first order markov process we analyze the set of collusive equilibria available to firms emphasizing the best collusive scheme for the firms at the start of the game in general there is a trade off between productive efficiency whereby the low cost firm serves the market in a given period and high prices we show that when costs are perfectly correlated over time within a firm if the distribution of costs is log concave and firms are sufficiently patient then the optimal collusive scheme entails price rigidity firms set the same price and share the market equally regardless of their respective costs when serial correlation of costs is imperfect partial productive efficiency is optimal for the case of two cost types first best collusion is possible if the firms are patient relative to the persistence of cost shocks but not otherwise we present numerical examples of first best collusive schemes

dynamic insurance with private information and balanced budgets this paper studies a dynamic insurance problem with bilateral asymmetric information and balanced budgets there are two infinitely lived agents in our model both risk averse and each has an i i d random endowment stream which is unobservable to the other in each period each agent must have a non negative consumption and together they must consume the entire aggregate endowment dynamic incentive compatibility in the nash sense is defined we give sufficient and necessary conditions for the existence of a constrained efficient contract we show that a constrained efficient contract can be characterized in a bellman equation we demonstrate that the long run distribution of expected utilities of each agent is not degenerate we also develop an algorithm for computing the efficient contract and in a numerical example we find that the consumption processes of the agents form stationary markov chains

repeated moral hazard and one sided commitment abstract this paper considers a repeated unobserved endowment economy with a restriction that agents can walk away from insurance contracts at the beginning of any period and contract with another insurer one sided commitment an equilibrium is derived characterized by a unique market determined insurance contract with the property that agents never want to walk away from it the paper shows that trade or insurance still occurs and that a non degenerate long run distribution of consumption exists a numerical example shows that this distribution is nearly log normal journal of economic literature classification numbers d30 d31 d80 d82

income fluctuation and asymmetric information an example of a repeated principal agent problem we examine a simple repeated principal agent model with discounting there are a risk averse borrower with an unobservable random income and a risk neutral lender the efficient contract is characterized it tends to the first best constant consumption contract as the discount factor tends to one and the time horizon extends to infinity if the time horizon is infinite and the contract is legally enforceable the borrower s utility becomes arbitrarily negative with probability one if the borrower has constant absolute risk aversion consumption is transferred between any two states at a constant interest rate which is less than the rate of time preference

endogenous information acquisition in coordination games in the context of a beauty contest coordination game in which payoffs 1 depend on the quadratic distance of actions from an unobserved state variable and 2 from the average action players choose how much costly attention to pay to vari 3 ous informative signals each signal has an underlying accuracy how precisely it 4 identifies the state and a clarity how easy it is to understand the unique linear 5 equilibrium has interesting properties the signals which receive attention are the 6 clearest available even if they have poor underlying accuracy the number of sig 7 nals observed falls as the complementarity of players actions rises and if actions 8 are more complementary the information endogenously acquired in equilibrium 9 is more public in nature the consequences of rational inattention constraints on 10

on repeated moral hazard with discounting in this paper we analyze optimal contracts in an infinitely repeated agency model in which both the principal and agent discount the future we show that there is a stationary representation of the optimal contract when the agent s conditional discounted expected utility is used as a state variable this representation reduces the multi period problem to a static variational problem which can be analyzed using standard variational techniques this reduction is used to obtain several properties of the contract

characterizing social value of information abstract this paper characterizes the social value of information in bayesian games with symmetric quadratic payoff functions and normally distributed public and private signals the main result provides a necessary and sufficient condition for welfare to increase with public or private information in so doing we represent welfare as a linear combination of the variance of a common term in an equilibrium strategy and that of an idiosyncratic term which are referred to as the common variance and the idiosyncratic variance of actions respectively the ratio of their coefficients is a key parameter in our condition if the coefficient of the common variance is relatively large welfare necessarily increases but if it is relatively small welfare can decrease using our condition we find eight types of games with different welfare effects of information