Smooth Structural Breaks Research Articles

OECD Ülkelerinde Yakınsama Hipotezinin Geçerliliği: Kalıntılarla Genişletilmiş Panel Fourier SURADF Birim Kök Testi

The main aim of this study is to improve the SURADF panel unit root test of Breur et al. (2001) by considering structural breaks and the knowledge of non-normal distrubited residuals. Chang et al. (2012) introduce a new panel unit root test by allowing smooth structural breaks in SURADF test process, in this study, we also take into account of the information of the residuals that are nonnormally distrubited. We test the validity of stochastic convergence among 18 OECD countries using this suggested new test and find a supportive evidence of convergence for only 7 countries.

Convergence Dynamics between South Africa and Her Main Trading Partners

The convergence of per capita GDP growth rates of less developed countries towards those of more industrialized economies is a central debate amongst growth economists. This study contributes to the literature by examining whether South Africa, as arguably Africa’s most developed economy, converges towards the growth of her main trading partners (i.e. Belgium, Botswana, China, Germany, India, Japan, Mozambique, Namibia, Netherlands, South Korea, United Arab Emirates (UAE), United Kingdom (UK), United States (US), Zambia and Zimbabwe). To this end, we examine the integration properties of per capita GDP differences between South Africa and each of her trading partners and we particularly employ unit root testing procedures which are robust to ESTAR-type nonlinearities and unobserved smooth structural breaks. Our empirical evidence points to convergence between South Africa and Belgium, Botswana, China, Germany, India, Japan, Mozambique, Namibia, Netherlands, South Korea, the UAE, the UK and the US but not with Zambia and Zimbabwe.

Smooth breaks and nonlinear mean reversion in real interest parity: Evidence from East Asian countries

ABSTRACTThis study aims to explore the empirical validity of the real interest rate parity (RIP) hypothesis for East Asian countries using Japan as the base country. To this end, we employ the recently proposed unit root tests of Christopoulos and Leon-Ledesma that account for both multiple smooth structural breaks of unknown form and nonlinear mean reversion in the series. Our empirical results uncover overwhelming evidences in favor of the RIP hypothesis for the whole countries in our sample. More specifically, through a Fourier approximation, it is observed that all real interest rate differentials display a mean-reverting behavior around an infrequently smooth-breaking mean, with the breaks being in accordance with the financial reforms and economic crises witnessed by the countries. Moreover, the degree of mean reversion appears to vary nonlinearly with the size of real interest rate appreciations and depreciations.

Natural resources as blessings and finance-growth nexus: A bootstrap ARDL approach in an emerging economy

This paper examines the link between financial development and economic growth in Pakistan by considering important role of natural resources in production function for the period of 1972–2017. Capital and labour are additional contributing factors of economic growth. To determine the integrating properties of the variables, we apply SOR unit root test containing information for sharp and smooth structural breaks in the series. We also employ the bootstrapping ARDL bounds testing approach to examine the cointegration between the factors of production. The causal relationship between financial development, natural resources, capital, labour and economic growth is tested by applying the VECM Granger causality test in the presence of structural breaks.The empirical findings indicate that financial development, natural resources, capital, labour and economic growth are cointegrated for long-run association. Additionally, financial development enhances domestic production as well as economic growth. Natural resources as blessings hypothesis is validated. Capital and labour also add to economic growth. The VECM Granger causality test results show the bidirectional causal relationship between financial development and economic growth. The feedback effect also exists between natural resources and economic growth. This paper helps policy makers in designing a comprehensive policy for strengthening finance-growth by using natural resources as an economic tool.

Environmental degradation in France: The effects of FDI, financial development, and energy innovations

This paper explores the determinants of carbon emissions in France by accounting for the significant role played by foreign direct investment (FDI), financial development, economic growth, energy consumption and energy research innovations in influencing CO2 emissions function. In this endeavour, we employ the novel SOR (Shahbaz et al. 2017) unit root test on French time series data over the period 1955–2016 to examine the order of integration in the presence of sharp and smooth structural breaks in the variables. We also apply the bootstrapping bounds testing approach, recently developed by McNown et al. (2018), to investigate the presence of cointegration and the empirical findings underscore the presence of cointegration among the time series. Moreover, we find that FDI has a positive impact, while energy research innovations have a negative impact, on French carbon emissions. Financial development lowers carbon emissions, thereby improving the French environmental quality. FDI degrades the environment, and thus supports the pollution-haven hypothesis in France. Similarly, financial development suggests that financial stability is a required condition for improving environmental quality, so are energy research innovations. Contrarily, energy consumption is positively linked with carbon emissions. However, the relationship between economic growth and CO2 emissions is an inverted-U, which is a validation of the environmental Kuznets curve (EKC).

Mean reversion in stock prices of seven Asian stock markets: Unit root test and stationary test with Fourier functions

This paper investigates whether stock prices in seven Asian stock markets can be characterized as random walk or mean reversion processes over the period December 1990 to March 2013. A Lagrange Multiplier (LM) Fourier unit root test proposed by Enders and Lee (2012) and a stationary test with a Fourier function proposed by Becker et al. (2006) are employed to approximate smooth structural breaks. The results of LM Fourier unit root test show that stock prices in all these seven stock markets demonstrate significant mean reversion. The results of the stationary test can be divided into two parts. When a level term is included in the model, the stock price of Thailand is mean-reverting while stock prices of other regions (Mainland China, HK, China, Japan, South Korea, Malaysia and Singapore) are non-stationary; when a trend term is included the stock prices in seven stock markets are all mean reversion processes.

Smooth structural breaks and the stationarity of the yen real exchange rates

This article examines and solves an interesting paradox in the literature that the tests for purchasing power parity (PPP) based on the yen real exchange rates (RERs) refute the PPP hypothesis more often than those with other major currency-based RERs, and the evidence is sensitive to the sample period used. Using a new empirical methodology accounting for both nonlinearity and multiple smooth temporary breaks in the data, we show that the puzzling finding is due to the failure to take into account the long but temporary large rise and fall in the yen RERs. The results illustrate that the yen RERs in the post-Bretton Woods period are likely mean reverting with linear or nonlinear adjustment toward large, long swing type of infrequent smooth temporary changes around constant equilibrium values, supporting the validity of PPP and resolving the paradox.

Investigating smooth breaks in real exchange rates

We investigate the validity of purchasing power parity of 7 Middle East countries over January 1980 to August 2008 by applying the stationary test with a nonlinear Fourier function as proposed by Becker et al. (2006). This test allows us to study the presence of unknown smooth structural breaks and the stationarity of real exchange rates. The empirical results indicate that PPP is not valid for most of these Middle East countries except the Bahrain and Israel.

Bayesian estimation of smoothly mixing time-varying parameter GARCH models

Smoothly time-varying (TV) GARCH models via an asymmetric logistic function mechanism are proposed, which are incorporated into the conditional volatility equation for capturing smooth structural breaks in the volatility of financial time series. The proposed models allow smooth transitions of varying “speed” between multiple, persistent regimes. A Bayesian computational method is employed to identify the locations of smooth structural transitions, and for estimation and inference, simultaneously accounting for heteroskedasticity. An informative prior is proposed to help ensure identification and allow accurate inference. The proposed methods are illustrated using simulated data, and an empirical study provides evidence for significant improvements in fit for the proposed smooth asymmetric time-varying volatility TV-GARCH models in two international stock market return series. A forecast study shows the proposed models significantly add to forecast accuracy for both volatility and Value-at-Risk.

Persistence in real exchange rate convergence

AbstractIn this paper we use a long memory framework to examine the validity of the Purchasing Power Parity (PPP) hypothesis using both monthly and quarterly data for a panel of 47 countries over a 50 year period (1957–2009). The analysis focuses on the long memory parameter d that allows us to obtain different convergence classifications depending on its value. Our analysis allows for the presence of smooth structural breaks and it does not rely on the use of a benchmark. Overall the evidence strongly points to the presence of a long memory process, where 0.5<d<1. The implication of our results is that we find long memory mean reverting convergence, something that is also consistent with Pesaran, M. H., R. P. Smith, T. Yamagata, and L. Hvozdyk. 2009. “Pairwise Tests of Purchasing Power Parity.” Econometric Reviews 28: 495–521. In explaining the speed of convergence as captured by the estimated long memory parameter d we find impediments to trade such as distance between neighboring countries and sticky prices to be mainly responsible for the slow adjustment of real exchange rates to PPP rather than nominal rates for all country groups but Asia, where the opposite is true.

A Unit Root Test Using a Fourier Series to Approximate Smooth Breaks*

AbstractWe develop a unit‐root test based on a simple variant of Gallant's (1981) flexible Fourier form. The test relies on the fact that a series with several smooth structural breaks can often be approximated using the low frequency components of a Fourier expansion. Hence, it is possible to test for a unit root without having to model the precise form of the break. Our unit‐root test employing Fourier approximation has good size and power for the types of breaks often used in economic analysis. The appropriate use of the test is illustrated using several interest rate spreads.

A pair-wise approach to output convergence between European regions

We apply the Pesaran (2007) pair-wise approach of convergence to the per capita outputs of 195 European regions for the period 1980–2006. Pesaran's approach is based on the computation of the percentage ratio of output gaps which fulfil a given convergence criterion. A high ratio will be interpreted in favour of convergence. In a first step, we define stochastic convergence between two regions as level stationarity of their output gap. Deviations from its equilibrium value will only have a temporary effect. Results from several usual unit root or stationarity tests show us that the percentage ratio of level stationary output gaps is low, which stands against this definition of convergence. However, this convergence criterion excludes the possibility of changes in output gap equilibrium value or catching up between regions. To fit these cases, we combine the pair-wise approach with unit root or stationarity tests with structural breaks. Structural breaks are modelled by dummies (Zivot and Andrews, 1992; Kurozumi,2002) or as smooth structural breaks (Christopoulos and León-Ledesma, 2009). Overall results are not changed as convergence is not accepted more often. Finally, we consider the autocorrelation function approach of Caggiano and Leonida (2009). Autocorrelations and their confidence intervals are estimated for each output gap. Convergence between two regions is accepted if their per capita output gap autocorrelations become nonsignificantly different from zero after some lag. Results show that a high percentage of regions satisfy this convergence criterion. Contrary to the conclusions which could be made from previous results, shocks to output gaps seem to disappear as time passes.