This article proposes a new panel unit root test based on Simes’ (1986) classical intersection test. The test is robust to general patterns of cross-sectional dependence and yet is straightforward to implement, only requiring <italic>p</italic>-values of time series unit root tests of the series in the panel,...

The Cauchy estimator of an autoregressive root uses the sign of the first lag as instrumental variable. The resulting IV <italic>t</italic>-type statistic follows a standard normal limiting distribution under a unit root case even under unconditional heteroscedasticity, if the series to be tested has no...

The paper examines the behavior of a generalized version of the nonlinear IV unit root test proposed by Chang (<CitationRef CitationID="CR6">2002</CitationRef>) when the series’ errors exhibit nonstationary volatility. The leading case of such nonstationary volatility concerns structural breaks in the error variance. We show that the...</citationref>

It was recently shown that time series cointegration tests, even in the presence of large sample sizes, often yield conicting conclusions (\mixed signals") as measured by, inter alia, a low correlation of empirical p-values. We present evidence suggesting that the problem of mixed signals...

While the limiting null distributions of cointegration tests are invariant to a certain amount of conditional heteroskedasticity as long as global homoskedasticity conditions are fulfilled, they are certainly affected when the innovations exhibit time-varying volatility. Worse yet, distortions...

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...

The puzzling Monte Carlo finding that the size distortion of meta-analytic panel unit root tests increases with the number of panel series is explained as the cumulative effect of arbitrarily small size distortions in the time series tests composing the panel test.

This paper suggests a combination procedure to exploit the imperfect correlation of cointegration tests to develop a more powerful meta test. To exemplify, we combine Engle and Granger (1987) and Johansen (1988) tests. Either of these underlying tests can be more powerful than the other one...

The Cauchy estimator of an autoregressive root uses the sign of the first lag as instrumental variable. The resulting IV <italic>t</italic>-type statistic follows a standard normal limiting distribution under a unit root case even under unconditional heteroscedasticity, if the series to be tested has no...