The role of innovation in improving productivity might vary according to a country's relative position in technology advancement. Frontier countries might benefit more from policies that promote firms' internal innovation (create), while follower countries would gain more from policies favoring...

This paper constructs estimators for panel data regression models with individual specific heterogeneity and two-sided censoring and truncation. Following Powell (1986) the estimation strategy is based on moment conditions constructed from re-censored or re-truncated residuals. While these...

Germany's water supply industry is characterized by a multitude of utilities and widely diverging prices, possibly resulting from structural differences beyond the control of firms' management, but also from inefficiencies. In this article we use Data Envelopment Analysis and Stochastic Frontier...

Germany's water supply industry is characterized by a multitude of utilities and widely diverging prices, possibly resulting from structural differences beyond the control of firms' management, but also from inefficiencies. In this article we use Data Envelopment Analysis and Stochastic Frontier...

Interaction terms are often misinterpreted in the empirical economics literature by assuming that the coefficient of interest represents unconditional marginal changes. I present the correct way to estimate conditional marginal changes in a series of non-linear models including (ordered)...

In this note I show that a typo in Stata’s help file may have contributed in wrongly estimating marginal changes after truncated and censored regression models. This has significant implications for empirical practice and results from published studies may need to be reconsidered.