The disruptive potential of PWLAN at the country-level: The cases of Germany,the UK,and the USA

This paper analyzes the impact of WLAN technologies for incumbent MNOs based on an empirical cross-country study of the players in the public WLAN-hotspot market using the theory of disruptive innovation and theoretical extensions for the industry- and country-level. The main research question to be analyzed is whether and why PWLAN has shown a disruptive or sustaining impact trend for incumbent MNOs in the hotspot markets of Germany, the UK, and the USA in recent years. The results imply that incumbent MNOs and new entrants have taken advantage of the opportunity provided by PWLAN, but the market success of both types of players varies between the countries analyzed. Incumbent MNOs dominate in Germany but not in the UK and the USA. The reasons for these country-specific differences were further investigated, and the results suggest that the analysis of disruptive potential in telecommunications needs to include country- and firm-specific factors, which are, again, largely influenced by the local regulation.     

Exact linear rank tests for two‐sample equivalence problems with continuous data

The present paper introduces a methodology for the semiparametric or non‐parametric two‐sample equivalence problem when the effects are specified by statistical functionals. The mean relative risk functional of two populations is given by the average of the time‐dependent risk. This functional is a meaningful non‐parametric quantity, which is invariant under strictly monotone transformations of the data. In the case of proportional hazard models, the functional determines just the proportional hazard risk factor. It is shown that an equivalence test of the type of the two‐sample Savage rank test is appropriate for this functional. Under proportional hazards, this test can be carried out as an exact level α test. It also works quite well under other semiparametric models. Similar results are presented for a Wilcoxon rank‐sum test for equivalence based on the Mann–Whitney functional given by the relative treatment effect.     

Industry evolution and R&D externalities

R&D externalities can imply ranges of aggregate increasing returns to scale in R&D. As a consequence several equilibria can exist involving different numbers of firms and different R&D investment levels. In a theoretical model the equilibrium dynamics are analyzed, showing that cyclical fluctuations of the number of firms and R&D investment may be expected, and that the long-run equilibrium is highly sensitive to investors' initial beliefs. The model is tested empirically using a unique database comprising competing firms in various R&D races.