This paper shows that a qualitative analysis can always be used in evaluating a model's validity both in general and compared to other hypothesized models. The analysis relates the sign patterns and possibly other information of hypothesized structural arrays to the sign pattern of the estimated...

This paper proposes a method for assessing the information content and validity of a mathematical structural model for which only the directions of influence among its endogenous and exogenous variables are known, as expressed by the sign patterns of associated arrays. The traditional literature...

We develop a dynamic general equilibrium model of education, quality and variety innovation, and scale-invariant growth. The early endogenous innovation-based growth models incorporate a scale effect predicting that larger economies are characterized by higher per capita growth rates. Recent...