Asymptotic behaviour of tests for a unit root against an explosive alternative

We compare the asymptotic local power of upper-tail unit root tests against an explosive alternative based on ordinary least squares (OLS) and quasi-differenced (QD) demeaning/detrending. We find that under an asymptotically negligible initialisation, the QD-based tests are near asymptotically efficient and generally offer superior power to OLS-based approaches; however, the power gains are much more modest than in the lower-tail testing context. We also find that asymptotically non-negligible initial conditions do not affect the power ranking in the same way as they do for lower-tail tests, with the QD-based tests retaining a power advantage in such cases.     

Markov-switching models and the unit root hypothesis in real US GDP

I find that real US GDP is better characterized as a trend stationary Markov-switching process than as having a (regime-dependent) unit root. I examine the effects of both assumptions on the analysis of business cycle features and their implications for the persistence of the dynamic response of output to a random disturbance.     

On testing for nonlinearity in multivariate time series

This paper considers a multivariate extension of the test for neglected nonlinearity proposed by Tsay (1986) that uses principal components to overcome the problem of dimensionality that is common with tests of this type. Monte Carlo experiments reveal that the modified multivariate test provides a significant dimensional reduction without suffering from any systematic level distortion or power loss, and is more powerful than univariate nonlinearity tests.     

A fractionally integrated exponential STAR model applied to the US real effective exchange rate

The aim of this paper is to study the dynamics of the US real effective exchange rate by capturing non-linearity and long-memory features. In this context, we use the family of fractionally integrated STAR (FISTAR) models proposed by van Dijk et al. (van Dijk, D., Franses, P.H., and Paap, R., 2002. A non-linear longmemory model with an application to US unemployment. Journal of Econometrics 110, 135–165.) in the case when the transition function is an exponential function and we develop an estimation procedure. Indeed, these models can take into account processes characterized by several distinct dynamic regimes and persistence phenomena.     

A simple spatial dependence test robust to local and distributional misspecifications

In this paper, we derive a class of modified score tests robust to local and distributional misspecifications for testing spatial error autocorrelation and spatial lag dependence. The proposed tests are general enough to include several popular tests for the spatial dependence as special cases. Moreover, we show that the popular test statistics proposed by Burridge (1980) and Anselin et al. (1996) are robust to distributional misspecification although they are derived under normality assumption.     

A simple and effective misspecification test for the double-hurdle model

The commonly-used version of the double-hurdle model rests on a rather restrictive set of statistical assumptions, which are very seldom tested by practitioners, mainly because of the lack of a standard procedure for doing so, although violation of such assumptions can lead to serious modelling flaws. We propose here a bootstrap-corrected conditional moment portmanteau test which is simple to implement and has good size and power properties.     

A simple panel stationarity test in the presence of serial correlation and a common factor

This paper develops a simple test à la Pesaran (2007) for the null hypothesis of stationarity in heterogeneous panel data with cross-sectional dependence in the form of a common factor in the disturbance. We also allow for serial correlation.     

Nonlinearity in real exchange rates: an approach with disaggregated data and a new linearity test

Employing disaggregated real exchange rates from nine European counties in 16 goods categories, we assess in this study the nonlinearity in the real exchange rates. Surprisingly, we find evidence for nonlinearity in only four (10) out of 143 series with the linearity test proposed by Harvey et al. (2008 Harvey, D. I., Leybourne, S. J. and Xiao, B. 2008. A powerful test for linearity when the order of integration is unknown. Studies in Nonlinear Dynamics and Econometrics, 12 Art 8[Web of Science ®] , [Google Scholar]) at the 5% (10%) significance level. This result differs greatly from those of Juvenal and Taylor (2008 Juvenal, L. and Taylor, M. P. 2008. Threshold adjustment of deviations from the law of one price. Studies in Nonlinear Dynamics and Econometrics, 12 Art 8[Web of Science ®] , [Google Scholar]), Imbs et al. (2003 Imbs, J., Mumtaz, H., Raven, M. O. and Rey, H. 2003. Nonlinearities and real exchange rate dynamics. Journal of the European Economic Association, 1: 639–49. [Crossref] , [Google Scholar]), Sarno et al. (2004 Sarno, L., Taylor, M. P. and Chowdhury, I. 2004. Nonlinear dynamics in deviations from the law of one price: a broad-based empirical study. Journal of International Money and Finance, 23: 1–25. [Crossref], [Web of Science ®] , [Google Scholar]) and Berka (2009 Berka, M. 2009. “Non-linear adjustment in law of one price deviations and physical characteristic of good”. In Review of International Economics Vol. 17, 51–73.  [Google Scholar]), who report ample evidence for nonlinearity for the same or similarly disaggregated real exchange rate datasets.     

Some cautions on the use of nonlinear panel unit root tests: Evidence from a modified series-specific non-linear panel unit-root test

The purpose of this paper is to examine the relevance of applying nonlinear panel unit root test to examine the non-linear mean reversion behaviors of real exchange rates. We find that nonlinear panel unit root test may achieve lower power performance as compared to its alternative of linear panel unit test when the data generating process does not contain significant non-linear components. This finding post cautions to researchers in modeling and testing real exchanges behavior. We also develop a modified series-specific nonlinear panel unit root test and find evidence in favor of purchasing power parity hypothesis for China's four ASEAN trading partners in the period of February 1997 to August 2009.     

The persistence in real exchange rate: Evidence from East Asian countries

In this article, we examine the degree of persistence in monthly real exchange rate of six East Asian countries in relation to their two major trading partners, the United States and Japan, to study the validity of PPP for the 1976:01–2009:03 period. To investigate the persistency in real exchange rate series, we use sum of the autoregressive (AR) coefficients and the confidence interval for it using grid-bootstrap procedure recently developed by Hansen (1999). We have two findings: first, we find evidence for high persistency in real exchange rate in terms of the Japanese yen for five countries and for four countries in terms of the US dollar the for the full and pre-crisis sample periods. Second, for the post-crisis period, the presence of low persistency in real exchange rate supports PPP for three countries in terms of the Japanese yen and five countries in terms of the US dollar. These findings indicate that real exchange rate series of five East Asian countries are mean-revert based on their exchange rate policies and East Asian countries can form a currency union.     

A risk-driven approach to exchange rate modelling

The paper presents a new approach to exchange rate modelling that augments the CHEER model with a sovereign credit default risk as perceived by financial investors making their decisions. In the cointegrated VAR system with nine variables comprised of the short- and long-term interest rates in Poland and the euro area, inflation rates, CDS indices and the zloty/euro exchange rate, four long-run relationships were found. Two of them link term spreads with inflation rates, the third one describes the exchange rate and the fourth one explains the inflation rate in Poland. Transmission of shocks was analysed by common stochastic trends. The estimation results were used to calculate the zloty/euro equilibrium exchange rate.     

Testing for efficiency in selected developing foreign exchange markets: An equilibrium-based approach

This paper proposes an alternative way of testing FOREX efficiency for developing countries. The FOREX market will be efficient if fully reflects all available information. If this holds, the actual exchange rate will not deviate significantly from its equilibrium rate. Moreover, the spot rate should deviate from its equilibrium rate by only transitory components (i.e. it should follow a white noise process). This test is applied to three Central and Eastern European Countries — members of the EU. Considering an LSTAR model we find no evidence of nonlinear adjustment in the misalignment series. So, linear unit root tests imply that the Poland/Euro FOREX market is efficient, the Czech/Euro FOREX market is not, while the Slovak/Euro FOREX market is quasi-efficient.     

Imputing rent in consumption measures,with an application to consumption poverty in Canada, 1997–2009

We consider two econometric problems in the measurement of poverty, both relating to rent imputation. First, we account for quality differences correlated with selection into owner‐occupied versus rental tenure. This correction increases estimated household consumption by 5% over uncorrected estimates and decreases estimated poverty rates quite dramatically. Second, we propose that measurement error induced by the imputation be corrected by imputing a consumption distribution, rather than a consumption level, for each household. This correction increases estimated poverty rates slightly. We use our methods to measure consumption poverty in Canada, and find that the imputation strategy used influences the patterns observed. For example, measured poverty among the elderly barely declines when one uses our methods, in contrast to the almost 6 percentage point reduction we find using traditional methods. In our assessment of the over‐time evolution of consumption poverty, we find that substantial progress has been made on overall poverty and on child poverty, but that poverty among the elderly hardly changed.     

Nonlinearities in the real exchange rates: new evidence from developed and developing countries

This paper investigates nonlinearities in the dynamics of real exchange rates. We use Monte Carlo simulations to establish the size properties of the Teräsvirta-Anderson test, when the dynamics of the real exchange rate is influenced by an exogenous process. In addition, we show that a modified nonlinearity test, which includes additional right-hand-side variables, performs much better than the original in both Monte Carlo exercises and in the actual data on 1431 bilateral real exchange rate series. Finally, we investigate the dynamics of the real exchange rate for both developed and developing countries using the modified test for the recent floating period. In general, the results find a greater incidence of nonlinear dynamics for developing country real exchange rates.     

Testing for PPP in developing countries using confirmatory analysis and different base countries: an application to Asian countries

Previous studies on PPP have tested either the null hypothesis of non-stationary or the null of a stationary real exchange rate and used the US as the base country and focused on industrialized countries. It has been argued that testing either null is insufficient to confirm the presence of PPP. It has also been noticed that the results are sensitive to the choices of the base country; for instance, the US versus Germany. In contrast to previous studies, this paper uses different unit root tests, confirmatory analysis, and different base countries to test PPP for a sample of developing countries in Asia during the current float. Overall, the results do not seem to be sensitive to the choice of the base country, and joint rejections are not present but joint non-rejections are far more common. Using Perron's test, which allows for a one-time break in the series, the results indicate evidence of stationarity for Indonesia, Korea, Malaysia and Thailand when the US is the base country. When Japan is the base country, evidence of stationarity is detected only for Indonesia.     

Comparisons of robust tests for shifts in trend with an application to trend deviations of real exchange rates in the long run

We study the finite sample properties of tests for structural changes in the trend function of a time series that do not require knowledge of the degree of persistence in the noise component. The tests of interest are the quasi-Feasible Generalized Least Squares (FGLS) procedure by Perron and Yabu (2009b Perron, P and Yabu, T. 2009b. Testing for shifts in trend with an integrated or stationary noise component. Journal of Business and Economic Statistics, 27: 369–96. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) and the weighted average of the regression t-statistics by Harvey et al. (2009 Harvey, DI, Leybourne, SJ and Taylor, AMR. 2009. Simple, robust, and powerful tests of the breaking trend hypothesis. Econometric Theory, 25: 995–1029. [Crossref], [Web of Science ®] , [Google Scholar]), both of which have the same limit distribution whether the noise component is stationary or has a unit-root. We analyse the finite sample size and power properties of these tests under a variety of Data-Generating Processes (DGPs). The results show that the Perron–Yabu test has greater power overall. With respect to the size, the Harvey–Leybourne–Taylor test exhibits larger size distortions unless a moving-average component is present. Using the Perron and Yabu procedure to test for structural changes in the trend function of long-run real exchange rates with respect to the US dollar indicates that for 17 out of 19 countries, the series have experienced a shift in trend since the late nineteenth century.     

A simple test for nonstationarity in mixed panels with incidental trends

Ng (2008) shows how the cross-sectional variance of the observed panel data can be used to construct a simple test for the proportion of non-stationary units. However, in the case with incidental trends the test is distorted. The present note shows how the distortions can be substantially reduced by the use of bias-adjustment. It also investigates the local power of the bias-adjusted test, which is shown to suffer from the same incidental trends problem previously only documented for conventional t$t$-tests.     

The long-run convergence of exchange rates and prices in the European Union

This paper provides tests of Purchasing Power Parity (PPP) for members of the EU-27 not in the euro area, using multivariate and panel cointegration techniques, for the period since the introduction of the euro currency in 1999 until the end of 2009. The results indicate that long-run PPP holds in ten cases and that domestic prices or the nominal exchange rate is the main driver of the short-run adjustment to stationarity. These results are discussed in terms of monetary convergence in the long-run.     

Internal and external exchange rate equilibrium in a cointegration framework. An application to the Spanish peseta

A simple cointegration methodology is used to compute the equilibrium real exchange rate for the peseta. The stock of foreign assets and the evolution of sectoral prices are considered to be the fundamentals for the real exchange rate. After testing for cointegration, we proceed to decompose the series into a permanent and a transitory component, following the method devised by Gonzalo and Granger. The permanent component of the real exchange rate corresponds to its (time-varying) equilibrium value, and the deviation of the actual real exchange rate from this equilibrium value gives an estimation of the degree of misalignment of the real exchange rate. By the end of the sample (1998:1), the peseta is estimated to be undervalued around 6%.     

The Feldstein-Horioka puzzle in African countries: A panel cointegration analysis

This paper investigates the Feldstein-Horioka coefficients for 37 African countries using the recently developed Pooled Mean Group (PMG), Fully Modified OLS (FMOLS), and Dynamic OLS (DOLS) panel cointegration techniques. The empirical findings reported in this paper reveal that savings and investment are non-stationary and cointegrated series. The estimated coefficients using FMOLS, DOLS, and PMG are 0.38, 0.58, and 0.36, respectively, for the sample as a whole for the period from 1970 to 2006. These results confirm previous studies' findings that capital was relatively mobile in African countries compared to OECD countries. In addition, our study shows that there are marked differences in savings retention coefficients for different country groups in Africa (CFA franc zone and non-CFA franc zone countries, oil-producing and non-oil-producing countries, civil law and common law countries). These results have some policy implications.