In this paper, several seasonal unit root tests are analysed in the context of structural breaks at known time and a new break corrected test is suggested. We show that the widely used HEGY test as well as an LM variant thereof are asymptotically robust to seasonal mean shifts of finite...

We assume that some consistent estimator of an equilibrium relation between non-stationary fractionally integrated series is used in a first step to compute residuals (or differences thereof). We propose to apply the semiparametric log-periodogram regression to the (differenced) residuals in...

We investigate economic and institutional determinants of ICT infrastructure for a broad cross section ofmore than 100 countries. The ICT variable is constructed from a principal components analysis. The explanatory variables are selected by variants of the Lasso estimator from the machine...

We propose a two-stage procedure for finding realistic benchmarks for nonparametric efficiency analysis. On the first stage the efficient DMUs are figured out by a free disposal hull approach. These benchmarks are directly targeted by directional distance functions and the extent of inefficiency...

In this paper we report the results from a detailed investigation of the shifts of the world production frontier function over the period 1980-2010. Analogous to a radar we implement a novel measurement approach for these shifts using nonparametrically computed productivity measures to scan the...

We apply various refinements of survival regression to assess the results of some basic specifications based on product life cycle theory for the case of a data set of the German automobile industry. The methods applied pay attention to biases in the coefficient estimates and the standard...

We conduct an empirical analysis of the technical efficiency of cars sold in Germany in 2010. The analysis is performed using traditional data envelopment analysis (DEA) as well as directional distance functions (DDF). The approach of DDF allows incorporating the reduction of carbon dioxide...

This study presents the results of an extensive Monte Carlo experiment to compare different methods of efficiency analysis. In addition to traditional parametric-stochastic and nonparametric-deterministic methods recently developed robust nonparametric-stochastic methods are considered. The...

In this paper we present a new approach to evaluate the environmental efficiency of decision making units. We propose a model that describes a two-stage process consisting of a production and an end-of-pipe abatement stage with the environmental efficiency being determined by the efficiency of...

This study explores the reduction potential of greenhouse gases for major pollution emitting countries of the world using nonparametric productivity measurement methods and directional distance functions. In contrast to the existing literature we apply optimization methods to endogenously...