The neoclassical growth model is used to identify the short‐run effects of neutral technology shocks, which affect the production of all goods homogeneously, and investment‐specific shocks, which affect only investment goods. The real equipment price, crucial for identifying the investment shocks, experiences an abrupt increase in its average rate of decline in 1982, so the analysis is based on a split sample. On the basis of the preferred specification, the two technology shocks account for 73 percent of hours’ and 44 percent of output’s business cycle variation before 1982, and 38 percent and 80 percent afterward. The shocks also account for more than 40 percent of hours’ and 58 percent of output’s forecast errors over a three‐ to eight‐year horizon in both samples. The majority of these effects are driven by the investment shocks.

A Bayesian consumer who is uncertain about the quality of an information source will infer that the source is of higher quality when its reports conform to the consumer's prior expectations. We use this fact to build a model of media bias in which firms slant their reports toward the prior beliefs of their customers in order to build a reputation for quality. Bias emerges in our model even though it can make all market participants worse off. The model predicts that bias will be less severe when consumers receive independent evidence on the true state of the world and that competition between independently owned news outlets can reduce bias. We present a variety of empirical evidence consistent with these predictions.

We analyze the optimal trading and ownership policy of a large shareholder who must trade off diversification and monitoring incentives. Without commitment, the problem is similar to durable goods monopoly: the share price today depends on expected future trades. We show that the large shareholder ultimately trades to the competitive price‐taking allocation, even though it entails inefficient monitoring. With continuous trading, the large shareholder trades immediately to this allocation if moral hazard is weak enough that her private valuation of a share is decreasing in her stake. Otherwise, the large shareholder adjusts her stake gradually. We consider implications for asset pricing, IPO underpricing, and lockup provisions.

We develop a framework for valuing improvements in health and apply it to past and prospective reductions in mortality in the United States. We calculate social values of (i) increased longevity over the twentieth century, (ii) progress against various diseases after 1970, and (iii) potential future progress against major diseases. Cumulative gains in life expectancy after 1900 were worth over $1.2 million to the representative American in 2000, whereas post-1970 gains added about $3.2 trillion per year to national wealth, equal to about half of GDP. Potential gains from future health improvements are also large; for example, a 1 percent reduction in cancer mortality would be worth $500 billion.

We incorporate multiagent, principal‐agent theory into general equilibrium analysis. The traded commodities are multiagent contracts that include a description of the individual’s job, effort level, and state‐contingent consumption. These contracts are club goods. The competitive equilibrium and the Pareto program are formulated. The contracts are identified with firms, so the market determines which firms exist and who is assigned to which firm in what capacity. An example is provided in which the internal organization of firms and the distribution of firm classes vary with the aggregate capital endowment and its distribution across agents. A simplex‐based algorithm for solving the Pareto program is developed.

We present and estimate a model in which the choice between entrepreneurship and wage work may be influenced by financial market imperfections. The model allows for limited liability, moral hazard, and a combination of both constraints. The paper uses structural techniques to estimate the model and identify the source of financial market imperfections using data from rural and semiurban households in Thailand. Structural, nonparametric, and reduced‐form estimates provide independent evidence that the dominant source of credit market imperfections is moral hazard. We reject the hypothesis that limited liability alone can explain the data.

Behavioral economics has demonstrated systematic decision‐making biases in both lab and field data. Do these biases extend across contexts, cultures, or even species? We investigate this question by introducing fiat currency and trade to a colony of capuchin monkeys and recovering their preferences over a range of goods and gambles. We show that capuchins react rationally to both price and wealth shocks but display several hallmark biases when faced with gambles, including reference dependence and loss aversion. Given our capuchins’ inexperience with money and trade, these results suggest that loss aversion extends beyond humans and may be innate rather than learned.

This paper considers the costs of reducing consumption of a good by making its production illegal and punishing apprehended illegal producers. We use illegal drugs as a prominent example. We show that the more inelastic either demand for or supply of a good is, the greater the increase in social cost from further reducing its production by greater enforcement efforts. So optimal public expenditures on apprehension and conviction of illegal suppliers depend not only on the difference between the social and private values from consumption but also on these elasticities. When demand and supply are not too elastic, it does not pay to enforce any prohibition unless the social value is negative. We also show that a monetary tax could cause a greater reduction in output and increase in price than optimal enforcement against the same good would if it were illegal, even though some producers may go underground to avoid a monetary tax. When enforcement is costly, excise taxes and quantity restrictions are not equivalent.