In this paper I analyze GMM estimation when the sample is not a random draw from the population of interest. I exploit auxiliary information, in the form of moments from the population of interest, in order to compute weights that are proportional to the inverse probability of selection. The...

Ashenfelter and Krueger's (1993) within-twin, measurement-error- corrected estimate of the return to schooling is about 13-16 percent. If their estimate is unbiased, then their results imply considerable downward measurement error bias in uncorrected within-twin estimates of the return to...

This paper considers estimation of a panel data model with disturbances that are autocorrelated across cross-sectional units. It is assumed that the disturbances are spatially correlated, based on some geographic or economic proximity measure. If the time dimension of the data is large, feasible...

This article summarizes our views on the role of an "aggregation bias" in explaining the PPP Puzzle, in response to the several papers recently written in reaction to our initial contribution. We discuss in particular the criticisms of Imbs, Mumtaz, Ravn and Rey (2002) presented in Chen and...

The paper examines the size and productivity of total intangible capital relative to total tangible capital for a large panel of Italian Manufacturing firms. In the analysis, we decompose total intangibles in two different ways: in intangibles expensed in firms' current accounts (as usually...

The identification of age, cohort (vintage), and period (year) effects in a panel of individuals or other units is an old problem in the social sciences, but one that has not been much studied in the context of measuring researcher productivity. In the context of a semi-parametric model of...

This paper shows that, with (partial) irreversibility, higher uncertainty reduces the impact effect of demand shocks on investment. Uncertainty increases real option values making firms more cautious when investing or disinvesting. This is confirmed both numerically for a model with a rich mix...

This paper investigates the deepening of the international division of labor and its effect on factor intensities in Japan, mainly focusing on the manufacturing sector. In the first half of the paper, we analyze the factor contents of trade and find that Japan's factor content net-exports of...