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...

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...

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>

type="main" xml:id="obes12048-abs-0001" <title type="main">Abstract</title> <p>Cross-section regressions often examine many candidate regressors. We use multiple testing procedures (MTPs) controlling the false discovery rate (FDR) — the expected ratio of false to all rejections — so as not to erroneously select variables...</p>

We derive the null distribution of the nonlinear unit root test proposed in Kapetanios et al. [Kapetanios, G., Shin, Y., Snell, A., 2003. Testing for a unit root in the nonlinear STAR framework. Journal of Econometrics 112, 359–379] when nonzero means or both means and deterministic trends...

We propose an IV panel unit root test robust to nonstationary error volatility. Its finite-sample performance is convincing even for many units and strong cross-correlation. An application to GDP prices illustrates the inferential impact of nonstationary volatility.

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...