Unit Root Tests for Panels in the Presence of Short-run and Long-run Dependencies: Nonlinear IV Approach
نویسندگان
چکیده
An IV approach, using as instruments nonlinear transformations of the lagged levels, is explored to test for unit roots in panels with general dependency and heterogeneity across cross-sectional units. We allow not only for the cross-sectional dependencies of innovations, but also for the presence of cointegration across cross-sectional levels. Unbalanced panels and panels with differing individual short-run dynamics and cross-sectionally related dynamics are also permitted. Panels with such cross-sectional dependencies and heterogeneities appear to be quite commonly observed in practical applications. Yet, none of the currently available tests can be used to test for unit roots in such general panels. We also more carefully formulate the unit root hypotheses in panels. In particular, using order statistics we make it possible to test for and against the presence of unit roots in some of the individual units for a given panel. The individual IV t-ratios, which are the bases of our tests, are asymptotically normally distributed and cross-sectionally independent. Therefore, the critical values of the order statistics as well as the usual average statistic can be easily obtained from simple elementary probability computations. We show via a set of simulations that our tests work well, while other existing tests fail to perform properly. As an illustration, we apply our tests to the panels of real exchange rates, and find no evidence for the purchasing power parity hypothesis, which is in sharp contrast with the previous studies. This version: January 28, 2005. JEL Classification: C12, C15, C32, C33.
منابع مشابه
Testing for Unit Roots in Small Panels with Short-run and Long-run Cross-sectional Dependencies
An IV approach, using as instruments nonlinear transformations of the lagged levels, is explored to test for unit roots in panels with general dependency and heterogeneity across cross-sectional units. We allow not only for the cross-sectional dependencies of innovations, but also for the presence of cointegration across cross-sectional levels. Unbalanced panels and panels with differing indivi...
متن کاملThe Effects of Oil Price Movement on Nigerian Macroeconomic Variables: Evidence from Linear near and Nonlinear ARDL Modelling
T he study seeks to investigate both linear and nonlinear effects of oil price movement on critical macroeconomic variables (output, price and exchange rate) in Nigeria using ARDL modeling approach. Previous studies substantially relied on linear methods using VAR approach to unravel this links without a clear conclusion. In an attempt to seek better results in this study, we employ both l...
متن کاملNonlinear IV Panel Unit Root Tests
This paper presents the nonlinear IV methodology as an effective inferential basis for nonstationary panels. The nonlinear IV method resolves the inferential difficulties in testing for unit roots arising from the intrinsic heterogeneities and cross-dependencies of panel models. Individual units are allowed to be dependent through correlations among innovations, interrelatedness of short-run dy...
متن کاملAn Application of the Two-Regime Threshold Vector Error Correction Model to Analyze Asymmetric Price Transmission of Milk in Zanjan Province of Iran
In this paper asymmetric price transmission mechanism and nonlinear adjustment between producer and retail prices of milk were examined in Zanjan Province of Iran. For this purpose, a Two-Regime Threshold Vector Error Correction Model (TVECM) and a Sup-LM Test developed by Hansen and Seo (2002) were employed for checking presence of a threshold effect. Application of unit root tests indicated...
متن کاملThe Asymetric Effect of Tax on Income Distribution in Iran
Abstract The main purpose of this study is to explore the relationship between “direct and indirect taxes” and “inequality of income distribution” in Iran. So, we have used annual time series data of the direct taxes to GDP ratio, indirect taxes to GDP ratio, and the Gini coefficient during 1982-2014. The results of the threshold unit root tests with an asymmetric adjustment show that all va...
متن کامل