The present thesis comprises two rather independent chapters. In general, the diagnosis and quantification of dependence is a major aim of econometric studies. Along these lines, the concept of dependence serves as an encompassing framework to analyze time series with two very different...

We investigate for 26 OECD economies whether their current account imbalances to GDP are driven by stochastic trends. Regarding bounded stationarity as the more natural counterpart of sustainability, results from Phillips-Perron tests for unit root and bounded unit root processes are contrasted....

Standard panel unit root tests (PURTs) are not robust to breaks in innovation variances. Consequently, recent papers have proposed PURTs that are pivotal in the presence of volatility shifts. The applicability of these tests, however, has been restricted to cases where the data contains only an...

In this dissertation new test statistics for the (panel) unit root hypothesis are presented. Besides a novel approach to testing the unit root hypothesis in univariate time series, the major part of this thesis is dedicated to unit root testing in cross sectionally dependent panels with...

We investigate for 26 OECD economies if their current account imbalances are driven by stochastic trends. Standard ADF results are contrasted with tests accounting for the bounded support of the current account. Neglecting the latter feature might give misleading results in the sense that ADF...

Noting that many economic variables display occasional shifts in their second order moments, we investigate the performance of homogenous panel unit root tests in the presence of permanent volatility shifts. It is shown that in this case, panel unit root tests derived under time invariant...