The so-called Cauchy estimator uses the sign of the first lag as instrument variable in autoregressions, and the resulting IV t-type statistic has a standard normal limiting distribution even in the unit root case. Thus, nonstandard asymptotics of the usual unit root tests such as the augmented Dickey-Fuller [ADF] test can be avoided. Moreover, the ADF test is affected by unconditional heterosk...

We estimate a unit root bilinear process using the Maximum Likelihood method with log-likelihood function constructed by means of the Kalman filter, and evaluate the finite sample properties of this estimator. One hundred and six world-wide price series are tested for unit root bilinearity applying the test suggested by Charemza et al. (2002b). Applying the Maximum Likelihood estimator based on...

This paper investigates the so-called one-step local quasi–maximum likelihood estimator for the unit root process with GARCH~1,1! errors+ When the scaled conditional errors ~the ratio of the disturbance to the conditional standard deviation! follow a symmetric distribution, the asymptotic distribution of the estimated unit root is derived only under the second-order moment condition+ It is show...

Most panel unit root tests are designed to test the joint null hypothesis of a unit root for each individual series in a panel. After a rejection, it will often be of interest to identify which series can be deemed to be stationary and which series can be deemed nonstationary. Researchers will sometimes carry out this classi.cation on the basis of n individual (univariate) unit root tests based...

The restricted likelihood ratio test, RLRT, for the autoregressive coefficient in autoregressive models has recently been shown to be second order pivotal when the autoregressive coefficient is in the interior of the parameter space and so is very well approximated by the χ1 distribution. In this paper, the non-standard asymptotic distribution of the RLRT for the unit root boundary value is obt...

This paper re-examines the stationarity of national health care expenditures and GDP in a panel setting utilizing data from 20 OECD countries over the period from 1960 to 1997. Previous research in this area has recognized the drawback of not allowing for structural breaks in their unit root tests and noted that their empirical results may not be robust. We advance the literature by utilizing a...

Recent approaches to testing for a unit root when uncertainty exists over the presence and timing of a trend break employ break detection methods, so that a with-break unit root test is used only if a break is detected by some auxiliary statistic. While these methods achieve near asymptotic e ciency in both xed trend break and no trend break environments, in nite samples pronounced \valleys" in...

This paper proposes a panel unit root test for micropanels with short time dimension (T ) and large cross section (N). There are several distinctive features of this test. First, the test is based on a panel AR(1) model, which allows for cross-sectional dependency, which is introduced by the initial condition’s assumption of a factor structure. Second, the test employs the panel AR(1) model wit...