The exact maximum likelihood estimate (MLE) provides a test statistic for the unit root test that is more powerful (Fuller, 1996, p. 577) than the usual least squares approach. In this paper a new derivation is given for the asymptotic distribution of this test statistic that is simpler and more direct than the previous method. The response surface regression method is used to obtain a fast alg...

Endogenous variables in structural models of agricultural commodity markets are typically treated as stationary. Yet, tests for unit roots have rather frequently implied that commodity prices are not stationary. This seeming inconsistency is investigated by focusing on alternative specifications of unit root tests. We apply various specifications to Illinois farm prices of corn, soybeans, barro...

This paper develops a wavelet (spectral) approach to test the presence of a unit root in a stochastic process. The wavelet approach is appealing, since it is based directly on the different behavior of the spectra of a unit root process and that of a short memory stationary process. By decomposing the variance (energy) of the underlying process into the variance of its low frequency components ...

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Panel unit root tests show that intranational purchasing power parity (PPP) cannot be rejected across major cities in Australia over the period from 1972 to 1999. The persistence of deviations in response to shocks is low, as measured by the estimated exact half-life of 5 to 7 quarters. This is much lower than results for similar tests done on US cities, and for international PPP tests. The foo...

We propose a unit root test for panels with cross-sectional dependency. We allow general dependency structure among the innovations that generate data for each of the cross-sectional units. Each unit may have di)erent sample size, and therefore unbalanced panels are also permitted in our framework. Yet, the test is asymptotically normal, and does not require any tabulation of the critical value...

This paper considers the estimation of average autoregressive roots-near-unity in panels where the time-series have heterogenous local-to-unity parameters. The pooled estimator is shown to have a potentially severe bias and a robust median based procedure is proposed instead. This median estimator has a small asymptotic bias that can be eliminated almost completely by a bias correction procedur...

In this paper we estimate the demand for exports and imports of manufactured goods for a panel containing the majority of the EU countries as well as the US and Japan. The model includes as explanatory factors both the traditional determinants of trade and also the stock of foreign direct investment (FDI). We apply panel unit root and cointegration tests allowing for heterogeneity. Whereas ther...

This paper investigates output convergence for the G7 countries using panel time-series techniques. We consider both the null hypotheses of no convergence and convergence. It is shown that inferences on output convergence depend on which one of the two null hypotheses is considered. Further, the no convergence results reported in previous studies using the time-series definition may be attribut...

This paper applies the recently developed econometric methods of panel unit root tests and non-linear mean-reversion to investigate price convergence in China --the largest transitional economy in the world. We find that prices did converge to the law of one price in China for an overwhelming majority of goods and services based on a large panel dataset. The finding sheds light on the extent of...