In the midst of a major U.S. military effort in Iraq and the Middle East, economists should be able to assess the relationship between U.S. troops and growth. The necessity of military force in providing security for nation-building is a common assumption among policymakers and international...

I show that in a conventional Ramsey model, between one-fourth and one-half of income differences across countries can be explained by a single factor: The steady-state effect of large, persistent differences in national average IQ on worker productivity. These differences in cognitive ability -...

Human capital plays an important role in the theory of economic growth, but it has been difficult to measure this abstract concept. We survey the psychological literature on cross-cultural IQ tests and conclude that modern intelligence tests provide one useful measure of human capital. Using a...

Good monetary policy requires estimates of all of its effects: monetary policy impacts traditional economic variables such as output, unemployment rates, and inflation. But does monetary policy influence crime rates? By extending the vector autoregression literature, we derive estimates of the...

Human capital plays an important role in the theory of economic growth, but it has been difficult to measure this abstract concept. We survey the psychological literature on cross-cultural IQ tests and conclude that intelligence tests provide one useful measure of human capital. Using a new...

Are more intelligent groups better at cooperating? A meta-study of repeated prisoner's dilemma experiments run at numerous universities suggests that students cooperate 5-8% more often for every 100-point increase in the school's average SAT score. This result survives a variety of robustness...

I show that in a conventional Ramsey model, between one-fourth and one-half of the global income distribution can be explained by a single factor: The effect of large, persistent differences in national average IQ on the private marginal product of labor. Thus, differences in national average IQ...

When money is added to a dynamic IS model, evidence from six countries indicates that money growth usually helps predict the GDP gap and that the predictive power of a short-term real interest is much weaker than previous work suggests. Thus, for dynamic IS models such as that used by Rudebusch,...