Knowledge that Transforms

We study symmetric information games where a number of senders choose what information to communicate. We show that the impact of competition on information revelation is ambiguous in general. We identify a condition on the information environment (i.e., the set of signals available to each sender) that is necessary and sufficient for equilibrium outcomes to be no less informative than the collusive outcome, regardless of preferences. The same condition also provides an easy way to characterize the equilibrium set and governs whether introducing additional senders or decreasing the alignment of senders' preferences necessarily increases the amount of information revealed.

This article studies multidimensional matching between workers and jobs. Workers differ in manual and cognitive skills and sort into jobs that demand different combinations of these two skills. To study this multidimensional sorting problem, I develop a theoretical framework that generalizes the unidimensional notion of assortative matching and sufficient conditions on the technology under which sorting obtains. I derive the equilibrium in closed form and use this explicit solution to study biased technological change. The main finding is that an increase in worker-job complementarities in cognitive relative to manual inputs leads to more pronounced sorting and wage inequality across cognitive relative to manual skills. This can trigger wage polarization and boost aggregate wage inequality. I then estimate the model for the U.S. and identify sizable technology shifts: during the last two decades, worker-job complementarities in cognitive inputs strongly increased, whereas complementarities in manual inputs decreased. In addition to this bias in complementarities, there has been a cognitive skill-bias in production. Counterfactual exercises suggest that these technology shifts (as opposed to changes in skill supply and demand) can account for observed changes in worker-job sorting, wage polarization and a significant part of the increase in U.S. wage dispersion.

We incorporate consumption indivisibilities into the Krugman (1980) model and show that an importer's per capita income becomes a primary determinant of “export zeros”. Households in the rich North (poor South) are willing to pay high (low) prices for consumer goods; hence, unconstrained monopoly pricing generates arbitrage opportunities for internationally traded products. Export zeros arise because some northern firms abstain from exporting to the South, to avoid international arbitrage. Rich countries benefit from a trade liberalization, while poor countries lose. These results hold also under more general preferences with both extensive and intensive consumption margins. We show that a standard calibrated trade model (that ignores arbitrage) generates predictions on relative prices that violate no-arbitrage constraints in many bilateral trade relations. This suggests that international arbitrage is potentially important.

A hyperbolic discounting model of labour supply and welfare participation with heterogeneous time preference parameters is estimated. Exclusion restrictions are constructed from variations in behaviour induced by time limits in a welfare reform experiment. We find that most individuals are time-inconsistent, and they exhibit varying degrees of present bias and perception of the commitment problem. Introducing a welfare component to the tax system can make individuals worse off by aggravating the commitment problem. Certain dynamic policy interventions carry sizeable commitment-related work incentives; for instance, a dynamic sanction triggered by past employment can be preferred by some individuals as a commitment device.

This article explores the sale of an object to an ambiguity averse buyer. We show that the seller can increase his profit by using an ambiguous mechanism. That is, the seller can benefit from hiding certain features of the mechanism that he has committed to from the agent. We then characterize the profit maximizing mechanisms for the seller and characterize the conditions under which the seller can gain by employing an ambiguous mechanism. Finally, we propose a class of ambiguous mechanisms that are easy to implement and perform better than the best non-ambiguous mechanism.

For many applications of signalling, senders rather than nature choose unobserved features such as their private choices of quality, capacity, investment, contract, or price, along with other actions that are (partially) observed by receivers. Despite the large number of different applications, these games have not been studied in any systematic way. We identify and study a general class of such games, which we call “endogenous signalling games”. These games normally suffer from a plethora of equilibria. To focus on reasonable equilibria, we propose to solve such games by requiring that the solution be invariant to a particular reordering of the senders’ moves. For a class of single-sender monotone endogenous signalling games, we show that the sender’s private choice can still have some commitment value even though it is not observed and that the sender’s signals must be exaggerated in equilibrium. Applications to loss-leader pricing, costly announcements, limit pricing, advertising, corporate financing, and private contracting are given.

Why do people vote? We design a field experiment to estimate a model of voting “because others will ask”. The expectation of being asked motivates turnout if individuals derive pride from telling others that they voted, or feel shame from admitting that they did not vote, provided that lying is costly. In a door-to-door survey about election turnout, we experimentally vary (1) the informational content and use of a flyer pre-announcing the survey, (2) the duration and payment for the survey, and (3) the incentives to lie about past voting. The experimental results indicate significant social image concerns. For the 2010 Congressional election, we estimate a value of voting “to tell others” of about $$$15, contributing 2 percentage points to turnout. Finally, we evaluate a get-out-the-vote intervention in which we tell potential voters that we will ask if they voted.

This article studies the impact of increasing trading frequency in financial markets on allocative efficiency. We build and solve a dynamic model of sequential double auctions in which traders trade strategically with demand schedules. Trading needs are generated by time-varying private information about the asset value and private values for owning the asset, as well as quadratic inventory costs. We characterize a linear equilibrium with stationary strategies and its efficiency properties in closed form. Frequent trading (more double auctions per unit of time) allows more immediate asset reallocation after new information arrives, at the cost of a lower volume of beneficial trades in each double auction. Under stated conditions, the trading frequency that maximizes allocative efficiency coincides with the information arrival frequency for scheduled information releases, but can far exceed the information arrival frequency if new information arrives stochastically. A simple calibration of the model suggests that a moderate market slowdown to the level of seconds or minutes per double auction can improve allocative efficiency for assets with relatively narrow investor participation and relatively infrequent news, such as small- and micro-cap stocks.

When designing data collection, crucial questions arise regarding how much data to collect and how much effort to expend to enhance the quality of the collected data. To make choice of sample design a coherent subject of study, it is desirable to specify an explicit decision problem. We use the Wald framework of statistical decision theory to study allocation of a budget between two or more sampling processes. These processes all draw random samples from a population of interest and aim to collect data that are informative about the sample realizations of an outcome. They differ in the cost of data collection and the quality of the data obtained. One may incur lower cost per sample member but yield lower data quality than another. Increasing the allocation of budget to a low-cost process yields more data, while increasing the allocation to a high-cost process yields better data. We initially view the concept of “better data” abstractly and then fix attention on two important cases. In both cases, a high-cost sampling process accurately measures the outcome of each sample member. The cases differ in the data yielded by a low-cost process. In one, the low-cost process has non-response and in the other it provides a low-resolution interval measure of each sample member’s outcome. In these settings, we study minimax-regret sample design for prediction of a real-valued outcome under square loss; that is, design which minimizes maximum mean square error. The analysis imposes no assumptions that restrict the unobserved outcomes. Hence, the decision maker must cope with both the statistical imprecision of finite samples and the partial identification of the true state of nature.

Many information structures generate correlated rather than mutually independent signals, the news media being a prime example. This article provides experimental evidence that many people neglect the resulting double-counting problem in the updating process. In consequence, beliefs are too sensitive to the ubiquitous “telling and re-telling of stories” and exhibit excessive swings. We identify substantial and systematic heterogeneity in the presence of the bias and investigate the underlying mechanisms. The evidence points to the paramount importance of complexity in combination with people’s problems in identifying and thinking through the correlation. Even though most participants in principle have the computational skills that are necessary to develop rational beliefs, many approach the problem in a wrong way when the environment is moderately complex. Thus, experimentally nudging people’s focus towards the correlation and the underlying independent signals has large effects on beliefs.