This paper describes a range of methods which have been proposed to study interactions in economic and social contexts. By interactions, we refer to interdependences between individual decisions which are not mediated by markets. These types of models have been employed to understand phenomena...

This paper proposes a method of testing whether a time series is a martingale. The procedure develops an asymptotic theory for the shape of the spectral distribution function of the first differences. Under the null hypothesis, this shape should be a diagonal line. several tests are developed...

This paper provides a framework for understanding the cross- section and time series approaches which have been used to test the convergence hypothesis. First, we present two definitions of convergence which capture the implications of the neoclassical growth model for the relationship between...

Although Tobin 1955 was one of the founding papers of the neoclassical one-sector growth model with smooth substitution between capital and labor, James Tobin's contributions to long-run growth theory throughout his career stood apart from other neoclassical growth models because of his emphasis...

This paper discusses the history of the use of cross-country regressions in modern growth economics. These regressions continue to be the workhorse of empirical growth analysis even though their meaning continues to be controversial. I argue that the early interpretations of these regressions...