A transactions model of the demand for multiple media of exchange is developed. Some results are expected, and others are both new and surprising. There are both extensive and intensive margins to currency substitution, and inflation may affect the two margins differently, leading to subtle...

Perpetual growth requires offsetting diminishing returns to reproducible factors of production. In this article we present a theory of factor elimination. For simplicity and clarity, there is no augmentation of non-reproducible factors, thus excluding the standard engine of growth. By spending...

Data quality in the Penn World Tables varies systematically across countries that have different growth rates and are at different stages of economic development, thus introducing measurement error correlated with variables of economic interest. We explore this problem with three examples from...