Knowledge that Transforms

We develop a new estimation methodology for dynamic optimization models with unobserved shocks and deterministic accumulation of the observed state variables. Investment models are an important example of such models. Our pairwise-difference approach exploits two common features of these models: (1) the monotonicity of the agent's decision (policy) function in the shocks, conditional on the observed state variables; and (2) the state-contingent nature of optimal decision making which implies that, conditional on the observed state variables, the variation in observed choices across agents must be due to randomness in the shocks across agents. We illustrate our procedure by estimating a dynamic trading model for the milk production quota market in Ontario, Canada.

This paper provides an exhaustive characterization of testability and identifiability issues in the collective framework in the absence of price variation; it thus provides a theoretical underpinning for a number of empirical works that have been developed recently. We first provide a simple and general test of the Pareto-efficiency hypothesis, which is consistent with all possible assumptions on the private or public nature of goods, all possible consumption externalities between household members, and all types of interdependent individual preferences and domestic production technology. The test is proved to be necessary and sufficient. We then provide conditions for the identification of the sharing rule and the Engel curves of individual household members for a variety of different observational schemes.

This paper investigates a possibly fundamental aspect of technological progress. If knowledge accumulates as technology advances, then successive generations of innovators may face an increasing educational burden. Innovators can compensate through lengthening educational phases and narrowing expertise, but these responses come at the cost of reducing individual innovative capacities, with implications for the organization of innovative activity—a greater reliance on teamwork—and negative implications for growth. Building on this “burden of knowledge” mechanism, this paper first presents six facts about innovator behaviour. I show that age at first invention, specialization, and teamwork increase over time in a large micro-data set of inventors. Furthermore, in cross-section, specialization and teamwork appear greater in deeper areas of knowledge, while, surprisingly, age at first invention shows little variation across fields. A model then demonstrates how these facts can emerge in tandem. The theory further develops explicit implications for economic growth, providing an explanation for why productivity growth rates did not accelerate through the 20th century despite an enormous expansion in collective research effort. Upward trends in academic collaboration and lengthening doctorates, which have been noted in other research, can also be explained in this framework. The knowledge burden mechanism suggests that the nature of innovation is changing, with negative implications for long-run economic growth.

This paper computes the change in welfare associated with the introduction of incentives. We calculate by how much the welfare gains of increased output due to incentives outweigh workers' disutility from increased effort. We accomplish this by studying the use of incentives by a firm in the check-clearing industry. Using this firm's production records, we model and estimate the worker's dynamic effort decision problem. We find that the firm's incentive scheme has a large effect on productivity, raising it by 12% over the sample period for the average worker. Using our parameter estimates, we show that the cost of increased effort due to incentives is equal to the dollar value of a 5% rise in productivity. Welfare is measured as the output produced minus the cost of effort; hence, the net increase in the average worker's welfare due to the introduction of the firm's bonus plan is 7%. Under a first-best scheme, we find that the net increase in welfare is 9%.

This paper presents a dynamic model of privatization, driven by improved institutional protection of private property rights and constrained by the buyer's financial constraints. Government ownership is more efficient than private ownership when private property rights are insecure. Improved institutional protection of property rights over time creates the need to privatize. The buyer's financial constraints affect the timing of privatization, causing the firm's post-privatization performance either to improve or to deteriorate in the short run. Financial constraints also have the possibility of inducing an underpricing phenomenon during privatization where the firm is priced below both what the buyer is willing to pay and the buyer's ability to pay. Faster institutional development calls for earlier privatization, but it also has the potential to either create or exacerbate deadweight losses associated with inefficient privatization. A host of empirically testable implications are derived.

In contexts ranging from public goods provision to information collection, a player's well-being depends on his or her own action as well as on the actions taken by his or her neighbours. We provide a framework to analyse such strategic interactions when neighbourhood structure, modelled in terms of an underlying network of connections, affects payoffs. In our framework, individuals are partially informed about the structure of the social network. The introduction of incomplete information allows us to provide general results characterizing how the network structure, an individual's position within the network, the nature of games (strategic substitutes vs. complements and positive vs. negative externalities) and the level of information shape individual behaviour and payoffs.

This paper proposes a method to measure strategic uncertainty by eliciting certainty equivalents analogous to measuring risk attitudes in lotteries. We apply this method by conducting experiments on a class of one-shot coordination games with strategic complementarities and choices between simple lotteries and sure payoff alternatives, both framed in a similar way. Despite the multiplicity of equilibria in the coordination games, aggregate behaviour is fairly predictable. The pure or mixed Nash equilibria cannot describe subjects' behaviour. We present two global games with private information about monetary payoffs and about risk aversion. While previous literature treats the parameters of a global game as given, we estimate them and show that both models describe observed behaviour well. The global-game selection for vanishing noise of private signals offers a good recommendation for actual players, given the observed distribution of actions. We also deduce subjective beliefs and compare them with objective probabilities.

In this article we argue that wage inequality and occupational mobility are intimately related. We are motivated by our empirical findings that human capital is occupation specific and that the fraction of workers switching occupations in the U.S. was as high as 16% a year in the early 1970's and had increased to 21% by the mid-1990's. We develop a general equilibrium model with occupation-specific human capital and heterogeneous experience levels within occupations. We find that the model, calibrated to match the level of occupational mobility in the 1970's, accounts quite well for the level of (within-group) wage inequality in that period. Next, we find that the model, calibrated to match the increase in occupational mobility, accounts for over 90% of the increase in wage inequality between the 1970's and the 1990's. The theory is also quantitatively consistent with the level and increase in the short-term variability of earnings.

We characterize optimal taxation of foreign capital and optimal sovereign debt policy in a small open economy where the government cannot commit to policy and seeks to insure a risk averse domestic constituency. The expected tax on capital is shown to vary with the state of the economy, generating cyclicality in investment and debt in an environment where the first best capital stock is a constant. The government's lack of commitment induces a negative correlation between investment and the stock of government debt, a "debt overhang'' effect. If the government discounts the future at a rate higher than the market, then capital oscillates indefinitely at a level strictly below the first best. Debt relief is never Pareto improving and cannot affect the long-run level of investment. Further, restricting the government to a balanced budget can eliminate the cyclical distortion of investment.

We study two-sided markets with a finite number of agents on each side, and with two-sided incomplete information. Agents are matched assortatively on the basis of costly signals. Asymmetries in signalling activity between the two sides of the market can be explained by asymmetries either in size or in heterogeneity. Our main results identify general conditions under which the potential increase in expected output due to assortative matching (relative to random matching) is offset by the costs of signalling. Finally, we examine the limit model with a continuum of agents and point out differences and similarities to the finite version. Technically, the paper is based on the elegant theory about stochastic order relations among differences of order statistics, pioneered by Barlow and Proschan in 1966 in the framework of reliability theory.