Most macroeconomic models assume that aggregate output is generated by a specification for the production function with total physical capital as a key input. Implicitly this assumes that private and public capital stocks are perfect substitutes. In this paper we test this assumption by...

The productivity paradox has sparked a great deal of research during the past three decades. Unfortunately, neither the results of empirical research nor the theoretical explanations for the paradox provide a convincing answer to whether investments in information and communication technology...

When benchmarking production units by non-parametric methods like data envelopment analysis (DEA), an assumption has to be made about the returns to scale of the underlying technology. Moreover, it is often also relevant to compare the frontiers across samples of producers. Until now, no exact...