conditions for myopic valuation and serial independence of the market excess return in discrete time models in a multiperiod pure exchange world with investors displaying hara preferences conditions for period by period application of one period asset pricing models are derived first the future investment opportunity set may be uncertain provided that in every period a specific market portfolio variable depending on preferences is known as of the preceding date this variable need not be completely deterministic second conditions for a serially independent market excess return are derived these conditions render serial independence very unlikely hence estimation methods assuming serial independence are likely to yield biased results while multiperiod capital asset pricing models generally involve intertemporal interdependencies in the pricing of assets there exist conditions under which the multiperiod model becomes indistinguishable from a sequence of one period models if these conditions are met then the price of an asset with cash flows at various dates can be derived by applying the one period pricing model recursively period by period the valuation process then is called quasi myopic at every date

risk aversion and the intertemporal behavior of asset prices in this article we characterize economies in which both cash flows and forward prices follow random walks we show in the case of geometric random walks that the preferences of the representative investor are of the constant proportional risk aversion type we also show the conditions under which spot prices follow random walks and under which the equivalent martingale measure is non state dep endent

testing for asymmetric information in insurance markets the first goal of this paper is to provide a simple and general test of the presence of asymmetric information in contractual relationships within a competitive context we also argue that insurance data are particularly well suited to such empirical investigations to illustrate this claim we use data on contracts and accidents to investigate the extent of asymmetric information in the french market for automobile insurance using various parametric and nonparametric methods we find no evidence for the presence of asymmetric information in this market

frictionless commerce a comparison of internet and conventional retailers there have been many claims that the internet represents a new nearly frictionless market our research empirically analyzes the characteristics of the internet as a channel for two categories of homogeneous products books and cds using a data set of over 8 500 price observations collected over a period of 15 months we compare pricing behavior at 41 internet and conventional retail outlets we find that prices on the internet are 9 16 lower than prices in conventional outlets depending on whether taxes shipping and shopping costs are included in the price additionally we find that internet retailers price adjustments over time are up to 100 times smaller than conventional retailers price adjustments presumably reflecting lower menu costs in internet channels we also find that levels of price dispersion depend importantly on the measures employed when we compare the prices posted by different internet retailers we find substantial dispersion internet retailer prices differ by an average of 33 for books and 25 for cds however when we weight these prices by proxies for market share we find dispersion is lower in internet channels than in conventional channels reflecting the dominance of certain heavily branded retailers we conclude that while there is lower friction in many dimensions of internet competition branding awareness and trust remain important sources of heterogeneity among internet retailers

selling to overconfident consumers consumers may overestimate the precision of their demand forecasts this overconfidence creates an incentive for both monopolists and competitive firms to offer tariffs with included quantities at zero marginal cost followed by steep marginal charges this matches observed cellphone service pricing plans in the us and elsewhere an alternative explanation with common priors can be ruled out in favor of overconfidence based on observed customer usage patterns for a major us cellular phone service provider the model can be reinterpreted to explain the use of flat rates and late fees in rental markets and teaser rates on loans nevertheless firms may benefit from consumers losing their overconfidence

competition and price variation when consumers are loss averse we modify the salop 1979 model of price competition with differentiated products by assuming that consumers are loss averse relative to a reference point given by their recent expectations about the purchase consumers sensitivity to losses in money increases the price responsiveness of demand and hence the intensity of competition at higher relative to lower market prices reducing or eliminating price variation both within and between products when firms face common stochastic costs in any symmetric equilibrium the markup is strictly decreasing in cost even when firms face different cost distributions we identify conditions under which a focal price equilibrium where firms always charge the same focal price exists and conditions under which any equilibrium is focal

paying not to go to the gym how do consumers choose from a menu of contracts we analyze a novel dataset from three u s health clubs with information on both the contractual choice and the day to day attendance decisions of 7 752 members over three years the observed consumer behavior is difficult to reconcile with standard preferences and beliefs first members who choose a contract with a flat monthly fee of over 70 attend on average 4 3 times per month they pay a price per expected visit of more than 17 even though they could pay 10 per visit using a 10 visit pass on average these users forgo savings of 600 during their membership second consumers who choose a monthly contract are 17 percent more likely to stay enrolled beyond one year than users committing for a year this is surprising because monthly members pay higher fees for the option to cancel each month we also document cancellation delays and attendance expectations among other findings leading explanations for our findings are overconfidence about future self control or about future efficiency overconfident agents overestimate attendance as well as the cancellation probability of automatically renewed contracts our results suggest that making inferences from observed contract choice under the rational expectation hypothesis can lead to biases in the estimation of consumer preferences

entrepreneurship social mobility and income redistribution in south india development economists have been preoccupied with the problem of increasing the size of the gnp pie to the relative neglect of its distribution despite the recent disenchantment with the viewpoint that all classes share in the benefits of industrial growth empirical data on the distribution of income business opportunity and economic power are in short supply many of the studies on entrepreneurship and economic development when they are not apologetics for ruthless capitalist exploitation as paul baran suggests extol the achievements of the capitalist entrepreneur without examining class origins and monopoly advantage joseph schumpeter sees entrepreneurs irrespective of class origin as heroic figures with the dream and will to found a private kingdom to conquer adversity to achieve success for its own sake and to experience the joy of creation for gustav papanek 1967 the private entrepreneur who is frugal diligent far sighted remarkably able and willing to take political risks is in large part responsible for the success of pakistan in achieving rapid industrialization

comparison friction experimental evidence from medicare drug plans consumers need information to compare alternatives for markets to function efficiently recognizing this public policies often pair competition with easy access to comparative information the implicit assumption is that comparison friction the wedge between the availability of comparative information and consumers use of it is inconsequential because information is readily available and consumers will access this information and make effective choices we examine the extent of comparison friction in the market for medicare part d prescription drug plans in the united states in a randomized field experiment an intervention group received a letter with personalized cost information that information was readily available for free and widely advertised however this additional step providing the information rather than having consumers actively access it had an impact plan switching was 28 percent in the intervention group versus 17 percent in the comparison group and the intervention caused an average decline in predicted consumer cost of about 100 per year among letter recipients roughly 5 percent of the cost in the comparison group our results suggest that comparison friction can be large even when the cost of acquiring information is small and may be relevant for a wide range of public policies that incorporate consumer choice

an intertemporal general equilibrium model of asset prices this paper develops a continuous time general equilibrium model of a simple but complete economy and uses it to examine the behavior of asset prices in this model asset prices and their stochastic properties are determined endogenously one principal result is a partial differential equation which asset prices must satisfy the solution of this equation gives the equilibrium price of any asset in terms of the underlying real variables in the economy in this paper we develop a general equilibrium asset pricing model for use in applied research an important feature of the model is its integration of real and financial markets among other things the model endogenously determines the stochastic process followed by the equilibrium price of any financial asset and shows how this process depends on the underlying real variables the model is fully consistent with rational expectations and maximizing behavior on the part of all agents our framework is general enough to include many of the fundamental forces affecting asset markets yet it is tractable enough to be specialized easily to produce specific testable results furthermore the model can be extended in a number of straightforward ways consequently it is well suited to a wide variety of applications for example in a companion paper cox ingersoll and ross 7 we use the model to develop a theory of the term structure of interest rates many studies have been concerned with various aspects of asset pricing under uncertainty the most relevant to our work are the important papers on intertemporal asset pricing by merton 19 and lucas 16 working in a continuous time framework merton derives a relationship among the equilibrium expected rates of return on assets he shows that when investment opportunities are changing randomly over time this relationship will include effects which have no analogue in a static one period model lucas considers an economy with homogeneous individuals and a single consumption good which is produced by a number of processes the random output of these processes is exogenously determined and perishable assets are defined as claims to all or a part of the output of a process and the equilibrium determines the asset prices our theory draws on some elements of both of these papers like merton we formulate our model in continuous time and make full use of the analytical tractability that this affords the economic structure of our model is somewhat similar to that of lucas however we include both endogenous production and

the welfare performance of sequential pricing mechanisms consumers are commonly required to subscribe to particular tariff options before uncertainty regarding their future purchases gets resolved since the general comparison of welfare performance of different pricing mechanisms is ambiguous this article empirically evaluates the expected welfare associated with standard nonlinear pricing and optional tariffs by using information directly linked to the type of individual consumers results show that tariffs composed of nonlinear options do not necessarily outperform simpler pricing strategies in terms of expected profits furthermore evidence suggests that a menu of optional two part tariffs dominates any other pricing strategy from an expected welfare perspective

monetary policy for inattentive economies we offer a contribution to the analysis of optimal monetary policy we begin with a critical assessment of the existing literature arguing that most work is based on implausible models of inflation output dynamics we then suggest that this problem may be solved with some recent behavioral models which assume that price setters are slow to incorporate macroeconomic information into the prices they set a specific such model is developed and used to derive optimal policy in response to shocks to productivity and aggregate demand optimal policy is price level targeting base drift in the price level which is implicit in the inflation targeting regimes currently used in many central banks is not desirable in this model when shocks to desired markups are added optimal policy is flexible targeting of the price level that is the central bank should allow the price level to deviate from its target for a while in response to these supply shocks but it should eventually return the price level to its target path optimal policy can also be described as an elastic price standard the central bank allows the price level to deviate from its target when output is expected to deviate from its natural rate

a monetarist model of inflation abstract we consider an overlapping generations model with new money introduced via autocorrelated lump sum transfers hence the own rate of return on money is fixed implying that dynamic neutrality may fail due to inflation tax effects we derive a condition less restrictive than serial independence of monetary growth rates which is necessary as well as sufficient for neutrality we determine whether various properties of the joint distribution of monetary growth rates and inflation rates which are weaker than neutrality for example positive correlation between the two can be expected to obtain in general settings

sinking swimming or learning to swim in medicare part d under medicare part d senior citizens choose prescription drug insurance offered by numerous private insurers we examine nonpoor enrollees actions in 2006 and 2007 using panel data our sample reduced overspending by 298 on average with gains by 81 percent of them the greatest improvements were by those who overspent most in 2006 and by those who switched plans decisions to switch depended on individuals overspending in 2006 and on individualspecific effects of changes in their current plans the oldest consumers and those initiating medications for alzheimer s disease improved by more than average suggesting that real world institutions help overcome cognitive limitations

an economic analysis of the optimal information security investment in the case of a risk averse firm abstract this paper presents an analysis of information security investment from the perspective of a risk averse decision maker following common economic principles using the expected utility theory we find that for a risk averse decision maker the maximum security investment increases with but never exceeds the potential loss from a security breach and there exists a minimum potential loss below which the optimal investment is zero our model also shows that the investment in information security does not necessarily increase with increasing level of risk aversion of the decision maker relationships between vulnerability and investment effectiveness and two broad classes of security breach probability functions are examined leading to interesting insights that can be used as guidelines for managers to determine the optimal level of security investment for certain types of security threats faced by risk averse firms future research directions are discussed based on the limitations and possible extensions of this study

limited information capacity as a source of inertia abstract we derive optimal time dependent adjustment rules from shannon s 1948 information theory in a continuous time lq prediction problem with a costly rate of information acquisition processing the optimal prediction evolves smoothly but jumps at an optimally chosen frequency when fresh information accrues a more volatile and persistent target raises the information rate required to maintain a sampling frequency this cost effect moderates and may even reverse the benefit effect on the value of information so optimal inertia is unresponsive to and nonmonotonic in the predictability of the environment conventional models with a fixed cost per observation imply no such cost effect so inertia rises quickly in the predictability of the environment

costly information acquisition experimental analysis of a boundedly rational model the directed cognition model assumes that agents use partially myopic option value calculations to select their next cognitive operation the current paper tests this model by studying information acquisition in two experiments in the first experiment information acquisition has an explicit financial cost in the second experiment information acquisition is costly because time is scarce the directed cognition model successfully predicts aggregate information acquisition patterns in these experiments when the directed cognition model and the fully rational model make demonstrably different predictions the directed cognition model better matches the laboratory evidence jel d83

information choice technologies theories based on information costs or frictions have become increasing popular in macroeconomics and macro finance the literature has used various types of information choices such as rational inattention inattentiveness information markets and costly precision using a unified framework we compare these different information choice technologies and explain why some generate increasing returns and others particularly those where agents choose how much public information to observe generate multiple equilibria the results can help applied theorists to choose the appropriate information choice technology for their application and to understand the consequences of that modeling choice

adaptive behavior and economic theory the relationship between psychological and economic views of behavior once a subject of heavy dispute is now understood in a very similar way by practitioners of both these disciplines and of our sister social sciences in general terms we view or model an individual as a collection of decision rules rules that dictate the action to be taken in given situations and a set of preferences used to evaluate the outcomes arising from particular situation action combinations these decision rules are continuously under review and revision new decision rules are tried and tested against experience and rules that produce desirable outcomes supplant those that do not i use the term adaptive to refer to this trial anderror process through which our modes of behavior are determined if one is interested in modeling particular decisions in any very explicit way it is obviously necessary to think about rather narrow aspects of an individual s entire set of decision rules his or her personality experimental psychology has traditionally focused on the adaptive process by which decision rules are replaced by others in this tradition the influence of the subject s or as an economist says the agent s preferences this essay uses a series of examples to illustrate the use of rationality and adaptation in economic theory it is argued that these hypotheses are complementary and that stability theories based on adaptive behavior may help to narrow the class of empirically interesting equilibria in certain economic models an experiment is proposed to test this idea

rationality of self and others in an economic system in this paper i want to disentangle some of the senses in which the hypothesis of rationality is used in economic theory in particular i want to stress that rationality is not a property of the individual alone although it is usually presented that way rather it gathers not only its force but also its very meaning from the social context in which it is embedded it is most plausible under very ideal conditions when these conditions cease to hold the rationality assumptions become strained and possibly even self contradictory they certainly imply an ability at information processing and calculation that is far beyond the feasible and that cannot well be justified as the result of learning and adaptation let me dismiss a point of view that is perhaps not always articulated but seems implicit in many writings it seems to be asserted that a theory of the economy must be based on rationality as a matter of principle otherwise there can be no theory this position has even been maintained by some who accept that economic behavior is not completely rational john stuart mill 1909 bk 2 ch 4 argued that custom not competition governs much of the economic world but he adds that the only possible theory is that standard economic doctrine makes assumptions of rationality that have very strong implications for the complexity of individuals decision processes the most complete assumptions of competitive general equilibrium theory require that all future and contingent prices exist and be known in fact of course not all these markets exist the incompleteness of markets has several side consequences for rationality for one thing each decision maker has to have a model that predicts the future spot prices this is an informational burden of an entirely different magnitude than simply optimizing at known prices it involves all the complexity of rational analysis of data and contradicts the much praised informational economy of the price system it is also the case that equilibria become much less well defined similar problems occur with imperfect competition this research was supported by the office of naval research grant onr n00014 79 c 0685 at the center for research in organizational efficiency institute for mathematical studies in the social sciences stanford university stanford california

choosing the wrong calling plan ignorance and learning when a firm offers several tariff options to its customers the possibility arises that they will make an ex post mistake in tariff choice this occurs since consumers cannot commit to a certain purchase level at the time they subscribe to the service option and thus they might find out later that a different choice of tariff could have resulted in a lower payment for their actual level of consumption this is a common feature of increasingly important subscriptions markets in which buyers and sellers maintain long term nonanonymous relations and where learning induces interesting dynamics on the one hand buyers may learn their taste over time thus making the right choice as times goes by on the other hand the seller may design options to identify the type of each buyer and if possible to extract a higher proportion of their consumer surplus by offering tariff options that are better tailored to the profile of the consumer this paper focuses on the first type of learning in turn i document buyer behavior in a subscriptions market using data from a tariff experiment run by south central bell scb in kentucky during the second half of 1986 the most frequently studied case of subscriptions markets is the choice among optional calling plans ocps in the telephone industry this paper shows that contrary to the conven

allocative efficiency of markets with zero intelligence traders market as a partial substitute for individual rationality we report market experiments in which human traders are replaced by zero intelligence programs that submit random bids and offers imposing a budget constraint i e not permitting traders to sell below their costs or buy above their values is sufficient to raise the allocative efficiency of these auctions close to 100 percent allocative efficiency of a double auction derives largely from its structure independent of traders motivation intelligence or learning adam smith s invisible hand may be more powerful than some may have thought it can generate aggregate rationality not only from individual rationality but also from individual irrationality

a generalization of the brennan rubinstein approach for the pricing of derivatives this paper derives preference free option pricing equations in a discrete time economy where asset returns have continuous distributions there is a representative agent who has risk preferences with an exponential representation aggregate wealth and the underlying asset price have transformed normal distributions which may or may not belong to the same family of distributions those pricing results are particularly valuable a to show new sufficient conditions for existing risk neutral option pricing equations e g the blackscholes model and b to obtain new analytical solutions for the price of european style contingent claims when the underlying asset has a transformed normal distribution e g a negatively skew lognormal distribution a fundamental result in the valuation theory under uncertainty is that equilibrium asset prices depend on investors marginal utility functions in this framework assuming a discrete time trading model and asset returns with continuous distributions rubinstein 1976 and brennan 1979 are able to derive risk neutral valuation relations that is preference free option pricing equations with an implicit mean return equal to the interest rate these pricing results seem surprising but they simply explore the relationship between derivatives and their underlying asset the underlying asset has an absolute price and derivatives have relative prices in terms of the underlying asset price implying that in equilibrium all these prices depend on the risk premium of the underlying asset hence the price of the underlying asset can be used to eliminate the risk premium from the option pricing equations the risk neutral valuation relations might have interesting applications not only in financial investments but also in real assets and executive compensation plans these pricing results were obtained under restrictive conditions on preferences and distributions rubinstein 1976 obtains the black scholes model with constant proportional risk aversion cpra preferences he also assumes that aggregate consumption and the underlying asset are bivariate lognormally

consumer inertia choice dependence and learning from experience in a repeated decision problem abstract understanding when and how individuals think about real life problems is a central question in economics this paper studies the role of inertia inattention state dependence and learning the empirical setting is a tariff experiment when optional measured tariffs for local telephone calls were introduced unanticipatedly we find that consumers tend to align their choices of tariff and telephone use levels correctly despite low potential savings mistakes are not permanent as individuals actively engage in tariff switching in order to reduce the monthly cost of telephone service ignoring unobservable heterogeneity and the endogeneity of past choices would have reversed these results

implications of rational inattention abstract a constraint that actions can depend on observations only through a communication channel with finite shannon capacity is shown to be able to play a role very similar to that of a signal extraction problem or an adjustment cost in standard control problems the resulting theory looks enough like familiar dynamic rational expectations theories to suggest that it might be useful and practical while the implications for policy are different enough to be interesting