The correlation between instruments and explanatory variables is a key determinant of the performance of the instrumental variables estimator. The R² from regressing the explanatory variable on the instrument vector is a useful measure of relevance in univariate models, but can be misleading...

In a 1991 essay in Scientific American, Michael Porter suggested that environmental regulation may have a positive effect on the performance of domestic firms relative to their foreign competitors by stimulating domestic innovation. We examine the stylized facts regarding environmental...

This paper explores the recent explosion in university patenting as a source of insight into the changing relationship between the university and the private sector. Before the mid-1980s, university patents were more highly cited, and were cited by more diverse patents, than a random sample of...

We present a simple theory-based measure of the variations in aggregate economic efficiency: the gap between the marginal product of labor and the household's consumption leisure tradeoff. We show that this indicator corresponds to the reciprocal of the markup of price over social marginal cost,...