We propose new tools for visualizing large numbers of functional data in the form of smooth curves or surfaces. The proposed tools include functional versions of the bagplot and boxplot, and make use of the first two robust principal component scores, Tukey's data depth and highest density...

This paper analyzes the relationship between investment in information and communication technologies (ICT), non-ICT-investment, labor productivity and workplace reorganization. Firms are assumed to reorganize workplaces if the productivity gains arising from workplace reorganization exceed the...

In this paper it is tested which of the various alternative approaches for constructing knowledge spillover pools suggested in existing literature measures the extent to which a firm can costlessly receive external knowlegde best. Since knowledge spillovers are unmeasurable, a 'goodness of fit'...

In self-reported data usually a phenomenon called 'heaping' occurs, i.e. survey participants round the values of their income, weight or height to some degree. Additionally, respondents may be more prone to round off or up due to social desirability. By ignoring the heaping process a severe bias...

This paper presents an analysis of changes in the distribution of gross household income and income inequality over the period 1983–1998. The analysis applies a semiparametric approach to study the effects of changes in the distribution of household types, and changes in National...

Virtually all empirical firm-level studies on the demand for labor do not include labor cost in the econometric specification. This is due to the fact that business and innovation survey data usually lack information on labor cost. This paper shows how reliable skill-specific and firm-specific...

This paper uses Data Envelopment Analysis (DEA) model formulations in order to determine the performance levels of 16 departments of the University of Thessaly. Particularly, the constant returns to scale (CRS) and variable returns to scale (VRS) models have been applied alongside with bootstrap...

Composite spatial data on administrative area level are often presented by maps. The aim is to detect regional differences in the concentration of subpopulations, like elderly persons, ethnic minorities, low-educated persons, voters of a political party or persons with a certain disease....

Standard fixed symmetric kernel type density estimators are known to encounter problems for positive random variables with a large probability mass close to zero. We show that in such settings, alternatives of asymmetric gamma kernel estimators are superior but also differ in asymptotic and...