This paper points to some of the facts that have emerged from 20 years of research into the analysis of unit roots in panel data, an area that has been heavily influenced by two studies, IPS (Im, Pesaran, and Shin, 2003) and LLC (Levin et al., 2002). Some of these facts are known, others are...

In a recent study, Westerlund (Empir Econ 37:517–531, <CitationRef CitationID="CR37">2009</CitationRef>) shows that the performance of the popular LLC (Levin et al., J Econ 108:1–24, <CitationRef CitationID="CR22">2002</CitationRef>) panel unit root test depends critically on the choice of lag truncation used when correcting for serial correlation, and that it is only when this...</citationref></citationref>

In a search for more powerful unit root tests, some researchers have recently proposed accounting for the information contained in the GARCH of the innovations. However, while promising, tests with GARCH are difficult to implement, which has made them quite uncommon in the empirical literature....

The cross-section average (CA) augmentation approach of Pesaran (2007) and Pesaran et al. (2013), and the principal components-based panel analysis of non-stationarity in idiosyncratic and common components (PANIC) of Bai and Ng (2004, 2010) are among the most popular “second-generation”...

The use of factor-augmented panel regressions has become very popular in recent years. Existing methods for such regressions require that the common factors are strong, such that their cumulative loadings rise proportionally to the number of cross-sectional units, which of course need not be the...

This paper proposes a new panel unit root test based on the generalized method of moments approach for panels with a small number of time periods and a large number of cross-section units, N. In the model that we consider the deterministic trend function is essentially unrestricted and the...

Most empirical evidence suggest that the Fisher effect, stating that inflation and nominal interest rates should cointegrate with a unit slope on inflation, does not hold, a finding at odds with many theoretical models. This paper argues that these results can be attributed in part to the low...

One of the single most cited studies within the field of nonstationary panel data analysis is that of LLC (Levin, Lin and Chu, 2002. Unit Root\linebreak Tests in Panel Data: Asymptotic and Finite Sample Properties. \emph{Journal of Econometrics} 98, 1-24), in which the authors propose a test for...