Daniele Coen-Pirani

Why Have Aggregate Skilled Hours Become So Cyclical Since the Mid-1980’s?

This paper documents and discusses a dramatic change in the cyclical behavior of aggregate hours worked by individuals with a college degree (skilled workers) since the mid-1980’s. Using the CPS outgoing rotation data set for the period 1979:1-2003:4, we find that the volatility of aggregate skilled hours relative to the volatility of GDP has nearly tripled since 1984. In contrast, the cyclical properties of unskilled hours have remained essentially unchanged. We evaluate the extent to which a simple supply/demand model for skilled and unskilled labor with capital-skill complementarity in production can help explain this stylized fact. Within this framework, we identify three effects which would lead to an increase in the relative volatility of skilled hours: (i) a reduction in the degree of capital-skill complementarity, (ii) a reduction in the absolute volatility of GDP (and unskilled hours), and (iii) an increase in the level of capital equipment relative to skilled labor. We provide empirical evidence in support of each of these effects. Our conclusion is that these three mechanisms can jointly explain about sixty percent of the observed increase in the relative volatility of skilled labor. The reduction in the degree of capital-skill complementarity contributes the most to this result.

Markups, Aggregation, and Inventory Adjustment

In this paper I suggest a unified explanation for two puzzles in the inventory literature: first, estimates of inventory speeds of adjustment in aggregate data are very small relative to the apparent rapid reaction of stocks to unanticipated variations in sales. Second, estimates of inventory speeds of adjustment in firm-level data are significantly higher than in aggregate data. The paper develops a multisector model where inventories are held to avoid stockouts, and price markups vary along the business cycle. The omission of countercyclical markup variations from inventory targets introduces a downward bias in estimates of adjustment speeds obtained from partial adjustment models. When the cyclicality of markups differs across sectors, this downward bias is shown to be more severe with aggregate rather than firm-level data. Similar results apply not only to inventories, but also to labor and prices. Montercarlo simulations of a calibrated version of the model suggest that these biases are quantitatively significant.

EFFECTS OF DIFFERENCES IN RISK AVERSION ON THE DISTRIBUTION OF WEALTH

This paper studies the role played by differences in risk aversion in affecting the long-run distribution of wealth across agents in the context of an endowment economy. The economy is populated by two types of Epstein-Zin agents who differ only in their attitudes toward risk. By choosing riskier portfolio strategies, less-risk-averse agents enjoy returns on their investments characterized by a higher mean and a higher variance than the ones enjoyed by more-risk-averse agents. The former effect tends to make less-risk-averse agents wealthier over time, whereas the latter tends to make them poorer. The paper shows that, contrary to the results obtained using standard expected utility preferences, for some parameter values the long-run distribution of wealth is dominated by more-risk-averse agents.

FIRM DYNAMICS IN AN URBAN ECONOMY

We develop a new dynamic general equilibrium model to explain firm entry, exit, and relocation decisions in an urban economy with multiple locations and agglomeration externalities. We characterize the stationary distribution of firms that arises in equilibrium. We estimate the parameters of the model using a method of moments estimator. Using unique panel data collected by Dun and Bradstreet, we find that agglomeration externalities increase the productivity of firms by up to 8%. Economic policies that subsidize firm relocations to the central business district increase agglomeration externalities in that area. They also increase economic welfare in the economy.

Estimating a Dynamic Equilibrium Model of Firm Location Choices in an Urban Economy

We develop a new dynamic general equilibrium model to explain firm entry, exit, and relocation decisions in an urban economy with multiple locations and agglomeration externalities. We characterize the stationary distribution of firms that arises in equilibrium. We estimate the parameters of the model using a method of moments estimator. Using unique panel data collected by Dun and Bradstreet, we find that our model fits the moments used in estimation as well as a set of moments that we use for model validation. Agglomeration externalities increase the productivity of firms by about 8 percent. Economic policies that subsidize firm relocations to the central business district increase agglomeration externalities in that area. They also increase economic welfare in the urban economy.

Human capital accumulation in a federation

More than half of the variation across U.S. school districts in real K-12 education expenditures per student is due to differences between, rather than within, states. I study the welfare implications of redistribution of education expenditures by the Federal government, using an analytically tractable model of human capital accumulation with heterogeneous agents and endogenous state policies. The net welfare effect of Federal redistribution depends on a trade-off between the positive effect of redistributing resources toward poorer states and the negative effect resulting from misallocation of population across states. Federal redistribution increases welfare in a calibrated version of the model.