Knowledge that Transforms

Taking advantage of unique longitudinal data, we provide the first characterization of what college students believe at the time of entrance about their final major, relate these beliefs to actual major outcomes, and provide an understanding of why students hold the initial beliefs about majors that they do. The data collection and analysis are based directly on a conceptual model in which a student's final major is best viewed as the end result of a learning process. We find that students enter school quite optimistic about obtaining a science degree, but that relatively few students end up graduating with a science degree. The substantial overoptimism about completing a degree in science can be attributed largely to students beginning school with misperceptions about their ability to perform well academically in science.

We introduce an approach for semiparametric inference in dynamic binary choice models that does not impose distributional assumptions on the state variables unobserved by the econometrician. The proposed framework combines Bayesian inference with partial identification results. The method is applicable to models with finite space of observed states. We demonstrate the method on Rust's model of bus engine replacement. The estimation experiments show that the parametric assumptions about the distribution of the unobserved states can have a considerable effect on the estimates of per-period payoffs. At the same time, the effect of these assumptions on counterfactual conditional choice probabilities can be small for most of the observed states.

We develop a decentralized Bayesian model of college admissions with two ranked colleges, heterogeneous students, and two realistic match frictions: students find it costly to apply to college, and college evaluations of their applications are uncertain. Students thus face a portfolio choice problem in their application decision, while colleges choose admissions standards that act like market-clearing prices. Enrollment at each college is affected by the standards at the other college through student portfolio reallocation. In equilibrium, student-college sorting may fail: weaker students sometimes apply more aggressively, and the weaker college might impose higher standards. Applying our framework, we analyse affirmative action, showing how it induces minority applicants to construct their application portfolios as if they were majority students of higher caliber.

We study the prevalence of the higher order risk attitudes of prudence and temperance in an experiment with a large demographically representative sample of participants. Under expected utility, prudence and temperance are defined by a convex first, and concave second, derivative of the utility function, and have direct implications for saving behaviour and portfolio choice. In the experiment, participants make pairwise choices that distinguish prudent from imprudent, and temperate from intemperate, behaviour. We correlate individuals' risk aversion, prudence, and temperance levels to their demographic profiles and their financial decisions outside the experiment. We observe that the majority of individuals' decisions are consistent with risk aversion, prudence, and temperance. Prudence is positively correlated with saving, as predicted by precautionary saving theory. Temperance is negatively correlated with the riskiness of portfolio choices.

We use the revealed preference method to derive a model of individual decision making when the endowment of an agent provides a reference point that may influence her choices. This model generalizes the classical rational choice model, which views choice as a consequence of “utility maximization”. Instead, our model sees choice as arising from “psychologically constrained utility maximization”, where the constraints are induced by one's initial endowment. In particular, this model produces status quo bias as a natural consequence (but not necessarily the endowment effect). A range of economic applications identify the predictive and explanatory strength of the model. In particular, we demonstrate that the status quo bias phenomenon reduces the size of the substitution effect in problems of consumption choice.

We show that even when the exchange rate cannot be devalued, a small set of conventional fiscal instruments can robustly replicate the real allocations attained under a nominal exchange rate devaluation in a dynamic New Keynesian open economy environment. We perform the analysis under alternative pricing assumptions—producer or local currency pricing, along with nominal wage stickiness; under arbitrary degrees of asset market completeness and for general stochastic sequences of devaluations. There are two types of fiscal policies equivalent to an exchange rate devaluation—one, a uniform increase in import tariff and export subsidy, and two, a value-added tax increase and a uniform payroll tax reduction. When the devaluations are anticipated, these policies need to be supplemented with a consumption tax reduction and an income tax increase. These policies are revenue neutral. In certain cases equivalence requires, in addition, a partial default on foreign bond holders. We discuss the issues of implementation of these policies, in particular, under the circumstances of a currency union.

When an individual performs several tasks simultaneously, processing resources must be allocated to different brain systems to produce energy for neurons to fire. Following the evidence from neuroscience, we model the brain as an organization in which a coordinator allocates limited resources to the brain systems responsible for the different tasks. Systems are privately informed about the amount of resources necessary to perform their task and compete to obtain the resources. The coordinator arbitrates the demands while satisfying the resource constraint. We show that the optimal mechanism is to impose to each system with privately known needs a cap in resources that depends negatively on the amount of resources requested by the other system. This allocation can be implemented using a biologically plausible mechanism. Finally, we provide some implications of our theory: (i) performance can be flawless for sufficiently simple tasks, (ii) the dynamic allocation rule exhibits inertia (current allocations are increasing in past needs), and (iii) different cognitive tasks are performed by different systems only if the tasks are sufficiently important.

Connections between individuals facilitate the exchange of goods, resources and information and create benefi ts. These connections may be exploited by adversaries to spread their attacks as well. What is the optimal way to design and defend networks in the face of attacks? We develop a model with a Designer and an Adversary. The Designer moves fi rst and chooses a network and an allocation of defense resources across nodes. The Adversary then allocates attack resources on nodes; if an attack succeeds then the Adversary decides on how successful resources should navigate the network. We obtain two principal results. One, we show that in a wide variety of circumstances a star network with all defence resources allocated to the central node is optimal for the Designer. Two, we identify conditions on the technology of conflict, network value function and the resource con guration for which networks with multiple hubs/components are optimal.

This article uses variation in access to a targeted lending program to estimate whether firms are credit constrained. While both constrained and unconstrained firms may be willing to absorb all the directed credit that they can get (because it may be cheaper than other sources of credit), constrained firms will use it to expand production, while unconstrained firms will primarily use it as a substitute for other borrowing. We apply these observations to firms in India that became eligible for directed credit as a result of a policy change in 1998, and lost eligibility as a result of the reversal of this reform in 2000, and to smaller firms that were already eligible for the preferential credit before 1998 and remained eligible in 2000. Comparing the trends in the sales and the profits of these two groups of firms, we show that there is no evidence that directed credit is being used as a substitute for other forms of credit. Instead, the credit was used to finance more production–there was a large acceleration in the rate of growth of sales and profits for these firms in 1998, and a corresponding decline in 2000. There was no change in trends around either date for the small firms. We conclude that many of the firms must have been severely credit constrained, and that the marginal rate of return to capital was very high for these firms.

We estimate an equilibrium model of ticket resale in which consumers ’ and brokers ’ decisions in the primary market reflect rational expectations about the resale market. Estimation is based on a unique dataset that merges transaction details from both the primary and secondary markets for tickets to major rock concerts. In our model, the presence of a resale market permits tickets to be traded from low-value to high-value consumers, but it also stimulates costly efforts by consumers and brokers to obtain underpriced tickets in the primary market. We estimate that observed levels of resale increase allocative efficiency by 5 % on average, but that a third of this increase is offset by increases in costly rent-seeking in the primary market and transaction costs in the resale market.