There were three important changes in the United States economy during the 1980s. First, from 1982-90, the decade featured the longest consecutive stretch of positive quarterly output growth in United States history. Second, wage inequality expanded greatly as the wages of highly skilled workers grew markedly faster than the wages of less skilled workers (Katz and Murphy (1992)). Finally, consumption inequality also expanded as the consumption of highly skilled workers grew faster than that of less skilled workers (Attanasio and Davis (1994)). This paper argues that these three aspects of the United States economic experience can be interpreted as being part of an efficient response to a macroeconomic shock given the existence of a particular technological impediment to full insurance. I examine the properties of efficient allocations of risk in an economic environment in which the outside enforcement of risksharing arrangements is infinitely costly. In these allocations, relative productivity movements have effects on both the current and future distribution of consumption across individuals. If preferences over consumption and leisure are nonhomothetic, these changes in the allocation of consumption will generate persistent cycles in aggregate output that do not occur in efficient allocations when enforcement is costless.

This paper develops a unified model of growth, population, and technological progress that is consistent with long-term historical evidence. The economy endogenously evolves through three phases. In the Malthusian regime, population growth is positively related to the level of income per capita. Technological progress is slow and is matched by proportional increases in population, so that output per capita is stable around a constant level. In the post-Malthusian regime, the growth rates of technology and total output increase. Population growth absorbs much of the growth of output, but income per capita does rise slowly. The economy endogenously undergoes a demographic transition in which the traditionally positive relationship between income per capita and population growth is reversed. In the Modern Growth regime, population growth is moderate or even negative, and income per capita rises rapidly. Two forces drive the transitions between regimes: First, technological progress is driven both by increases in the size of the population and by increases in the average level of education. Second, technological progress creates a state of disequilibrium, which raises the return to human capital and induces parents to substitute child quality for quantity.

We study the asset pricing implications of a multi-agent endowment economy where agents can default on debt. We build on the environment studied by Kocherlakota (1995) and Kehoe and Levine (1993). We present an equilibrium concept for an economy with complete markets and with endogenous solvency constraints. These solvency constraints prevent default, but at the cost of reduced risk sharing. We show that versions of the classical welfare theorems hold for this equilibrium definition. We characterize the pricing kernel, and compare it to the one for economies without participation constraints: interest rates are lower and risk premia depend on the covariance of the idiosyncratic and aggregate shocks.