Path Dependence in Aggregate Output

This paper studies an economy in which incomplete markets and strong complementarities interact to generate path dependent aggregate output fluctuations. An economy is said to be path dependent when the effect of a shock on the level of aggregate output is permanent in the absence of future offsetting shocks. Extending the model developed in Durlauf 11991(a),(b)). we analyze the evolution of an economy which consists of a countable infinity of industries. The production functions of individual firms in each industry are nonconvex and are linked through localized technological complementarities. The productivity of each firm at t is determined by the production decisions of technologically similar industries at t-1. No markets exist which allow firms and industries to exploit complementarities by coordinating production decisions. This market incompleteness produces several interesting effects on aggregate output behavior. First, multiple stochastic equilibria exist in aggregate activity. These equilibria are distinguished by differences in both the mean and the variance of output. Second, output movements are path dependent as aggregate productivity shocks indefinitely affect real activity by shifting the economy across equilibria. Third, when aggregate shocks are recurrent, the economy cycles between periods of boom and depression. Simulations of example economies illustrate how market incompleteness can produce rich aggregate dynamics.

Social Capital

This paper surveys research on social capital. We explore the concepts that motivate the social capital literature, efforts to formally model social capital using economic theory, the econometrics of social capital, and empirical studies of the role of social capital in various socioeconomic outcomes. While our focus is primarily on the place of social capital in economics, we do consider its broader social science context. We argue that while the social capital literature has produced many insights, a number of conceptual and statistical problems exist with the current use of social capital by social scientists. We propose some ways to strengthen the social capital literature.

Social Capital

This paper surveys research on social capital. We explore the concepts that motivate the social capital literature, efforts to formally model social capital using economic theory, the econometrics of social capital, and empirical studies of the role of social capital in various socioeconomic outcomes. While our focus is primarily on the place of social capital in economics, we do consider its broader social science context. We argue that while the social capital literature has produced many insights, a number of conceptual and statistical problems exist with the current use of social capital by social scientists. We propose some ways to strengthen the social capital literature.development, growth, identification, inequality, networks, social capital, trust,

Elements of a Theory of Design Limits to Optimal Policy

This paper presents a framework for understanding the limits that exist in optimal policy design in dynamic contexts. We consider the design of policies in the context of dynamic linear models. Fundamental design limits exist for policy rules in such environments in the sense that any policy rule embodies tradeoffs between the magnitudes of different frequency-specific components of the variance. Hence policies that are effective in eliminating low frequency variance components of a state variable can only do so at the cost of exacerbating high frequency variance components, and vice versa. Examples of the implications of such tradeoffs are considered.

Social Interactions

Prepared for Annual Reviews of Economics.

Discrete Choice with Social Interactions I: Theory

This paper provides an analysis of aggregate behavioral outcomes when individual utility exhibits social interaction effects. We study generalized logistic models of individual choice which incorporate terms reflecting the desire of individuals to conform to the behavior of others in an environment of noncooperative decisionmaking. Laws of large numbers are generated in such environments. Multiplicity of equilibria in these models, which are equivalent to the existence of multiple self-consistent means for average choice behavior, will exist when the social interactions exceed a particular threshold. Local stability of these multiple equilibria is also studied. The properties of the noncooperative economy are contrasted with the properties of an economy in which a social planner determines the set of individual choices. The model is additionally shown to be well suited to explaining a number of empirical phenomena, such as threshold effects in individual behavior, ethnic group fixed effects of income equations, and large cross-group differences in binary choice behavior.

Multinomial Choice with Social Interactions

This paper develops a model of individual decisionmaking in the presence of social interactions when the number of available choices is finite. We show how a multinomial logit model framework may be used to model such decisions in a way that permits a tight integration of theory and econometrics. Conditions are given under which aggregate choice behavior in a population exhibits multiple self-consistent equilibria. An econometric version of the model is shown to be identified under relatively weka conditions. That analysis is extended to allow for general error distributions and some preliminary ways to account for the endogeneity of group memberships are developed.

Output Persistence, Economic Structure, and the Choice of Stabilization Policy

macroeconomics, stabilization policy, output, economic structure

Nonergodic Economic Growth

This paper explores the role of complementarities and coordination failure in economic growth. We analyze the evolution composed of a countable set of infinitely-lived heterogenous industries. Individual industries exhibit nonconvexities in production and are linked across time through localized technological complementarities. Each industry employs one of two production techniques. One technique is more efficient in using capital than the other, but requires the payment of a fixed capital cost. Both techniques exhibit technological complementarities in the sense that the productivity of capital invested in a technique is a function of the technique choices made by various industries the previous period. These complementarities, when strong enough, interact with incompleteness of markets to produce multiple Pareto-rankable equilibria in ling run economic activity. The equilibria have a simple probabilistic structure that demonstrates how localized coordination failures can affect the aggregate equilibrium. The model is capable of generating interesting aggregate dynamics as coordination problems become the source of aggregate volatility. Modifications of the model illustrate how leading sectors can cause a takeoff into high growth.

Is God in the Details? A Reexamination of the Role of Religion in Economic Growth

Barro and McCleary (2003) is a key research contribution in the new literature exploring the macroeconomic effects of religious beliefs. This paper represents an effort to evaluate the strength of their claims. We evaluate their results in terms of replicability and robustness. Overall, their analysis generally meets the standard of statistical replicability, though not perfectly. On the other hand, we do not find that their results are robust to changes in their baseline statistical specification. When model averaging methods are employed to integrate information across alternative statistical specifications, little evidence survives that religious variables help to predict cross-country income differences.Economic Growth, Religion, Model Uncertainty