We propose a monitoring procedure to detect a structural change from stationary to integrated behavior. When the procedure is applied to the errors of a relationship between integrated series it thus monitors a structural change from a cointegrating relationship to a spurious regression. The...

Large regional unemployment disparities are a common feature of the labor market in many countries. This study deals with the question whether regional unemployment disparities in western Germany widen, become narrower or remain constant over time. It examines the hypothesis of convergence for...

There has been mixed evidence regarding the existence of rational bubbles in the foreign exchange markets. This paper introduces recently developed sequential unit root tests into the analysis of exchange rates bubbles. We find strong evidence of explosive behavior in the nominal Sterling-dollar...

The slow recovery following the 2008/2009 recession has led to renewed interest in the question whether deep recessions lower real GDP permanently or whether we can expect a rebound to earlier trend levels. Using a recent quantile autoregression unit root test we check whether shocks to real GDP...

This paper argues that typical applications of panel unit root tests should take possible nonstationarity in the volatility process of the innovations of the panel time series into account. Nonstationarity volatility arises for instance when there are structural breaks in the innovation...