Knowledge that Transforms

Despite the widespread belief that entrepreneurship is a key factor in economic development, there have been few attempts to develop formal models to analyze the phenomenon. This paper presents a model in which endogenous entrepreneurial activity is a key determinant of economic growth. The theory also differs from standard models in that growth is driven by the imitative activities of entrepreneurs. Previous theories have focused on the direct production of knowledge, underemphasizing the importance of imitation in the growth process. The paper also examines external effects arising from these entrepreneurial activities--effects distinct from those studied by Paul Romer.

We examine an exchange economy with two agents: one risk neutral with a certain endowment and a second risk averse with a random endowment. The realization of the endowment is public but can be falsified by the second agent at a cost. For a broad class of falsification cost functions the optimal no-falsification contract is noncontingent on a left-hand interval and strictly increasing with a slope strictly less than one on a right-hand interval. Under a mild further restriction, optimal no-falsification contracts are, in addition, piece-wise linear. Optimal contracts may in general require falsifying the state, but for a set of the highest endowment realizations there is no falsification. We find simple conditions under which the optimal contract is a no-falsification contract. The model has applications that include financial, insurance, and employment contracts and tax policy.

The main goal of this paper is to put forward a methodology for the measurement of product innovations using a value metric, that is, equating the "magnitude" of innovations with the welfare gains they generate. This research design is applied to the case of computed tomography scanners, a revolutionary innovation in medical technology. The econometric procedure centers on the estimation of a discrete choice model (the nested multinominal logit), which yields the parameters of a utility function defined over the changing quality dimensions of the innovative product. The estimated flow of social gains from innovation is used to compute a social rate of return to R & D, to explore the interrelation between innovation and diffusion, and to trace the time profile of benefits and costs, the latter suggesting the possible occurrence of "technological cycles."

We study the convergence of recursive least-squares learning schemes in economic environments in which there is private information. The presence of private information leads to the presence of hidden state variables from the viewpoint of particular agents. By applying theorems of Ljung, we extend some of our earlier results to characterize conditions under which a system governed by least-squares learning will eventually converge to a rational expectations equilibrium. We apply insights from the learning results to formulate and compute the equilibrium of a version of Townsend's model.

This paper describes two models of an agency that is collecting and reporting observations on a dynamical linear stochastic economy. The first is a "classical" model, with the agency reporting data that are the sum of a vector of "true" variables and a vector of measurement errors that are orthogonal to the true variables. The second is a model of an agency that uses an optimal filtering method to construct least-squares estimates of the true variables. These two models of the reporting agency imply different likelihood functions. A model of the investment accelerator is used as an example to illustrate the differing implications of the models.

The paper develops new methodology for the estimation of prewar GNP, taps previously unused data sources, and develops new estimates for the periods 1869-1908 and 1869-1928. Primary among the new data sources are direct measures of output in the transportation, communications, and construction sectors and estimates of the consumer price index. New measures of real GNP, nominal GNP, and the GNP deflator are developed. The new estimates of real GNP are as volatile on average over the business cycle as the traditional Kuznets-Kendrick series but dampen the amplitude of some cycles while raising the amplitude of others. The new estimates of the GNP deflator are distinctly less volatile than the traditional series and in fact no more volatile than those in the postwar period.

In the past, empirical research on charitable contributions has focused on two issues: estimating the income and price elasticities of contributions and estimating the extent to which government funding crowded out private contributions. The two fundamental problems in all these studies are the differences in the underlying conceptual models and the use of imperfect data for empirical analysis. This paper addresses both of these problems.

Gary Becker's "rotten kid theorem" asserts that if all family members receive gifts of money income from a benevolent household member, then even if the household head does not precommit to an incentive plan for family members, it will be in the interest of selfish family members to maximize total family income. The author shows by examples that the rotten kid theorem is not true without assuming transferable utility. He finds a simple condition on utility functions that is necessary and sufficient for there to be the kind of transferable utility needed for a rotten kid theorem. While restrictive, these conditions still allow one to apply the strong conclusions of the rotten kid theorem in an interesting class of examples.

It is almost universally agreed that individuals face incomplete insurance markets and cannot perfectly insure against the idiosyncratic risk. In this paper simple general equilibrium models with incomplete insurance markets are examined in order to assess the impact of imperfect insurance on the magnitude of the welfare costs of business cycles. Two versions of incomplete insurance markets are considered, and certain statistical properties of the equilibrium stochastic processes in these environments are compared with those of a perfect insurance economy.

We show that the seller's problem in devising an optimal auction is virtually identical to the monopolist's problem in third-degree price discrimination. More generally, many of the important results and elegant techniques developed in the field of mechanism design can be reinterpreted in the language of standard micro theory. We illustrate this by considering the problem of bilateral exchange with privately known values.