Testing the validity of PPP theory for African countries

This study examines the purchasing power parity theory for 14 African countries by applying a recent composite time series method that incorporates the Fourier approximation. The structural breaks are modelled as a gradual smooth process by means of a Fourier component. The Fourier unit root test failed to find any evidence showing that real exchange rates for these 14 countries have mean-reverting tendencies. However, both cointegration and Fourier cointegration tests detect a stable long-term relation between the nominal exchange rate and relative price levels for 8 out of 14 countries; moreover, for five countries Fourier component in cointegration analysis is found to suit quite well.     

PPP: Further evidence from Japanese regional data

This paper empirically analyzes Purchasing Power Parity (PPP) among Japanese municipalities from 1990 to 2003. Using panel unit root tests including one that considers cross-sectional dependence in the data (e.g., [Moon, H. R. and Perron, B. (2004). Testing for a unit root in panels with dynamic factors. Journal of Econometrics, 112, 81–126.]), we find evidence in favor of PPP, confirming the stationarity of relative prices in Japan and thus the long-run co-movement of municipal prices. Furthermore, the half-life of a shock is found to be about 2 years, which is faster than that of the international PPP. As in the European and US studies, short-term deviations from PPP can be explained by income differentials and distance between cities.     

Is the consumption-income ratio stationary in African countries? Evidence from new time series tests that allow for structural breaks

This article examines whether the consumption-income ratio is stationary in 50 African countries. We use the residual augmented least squares (RALS-LM) unit root test that allows for structural breaks. The empirical evidence shows that the consumption income ratio is stationary around structural breaks in most (44 out of 50) African countries. This is consistent with the predictions of most economic theories. The general finding of mean reversion implies that (policy) shocks are likely to have only temporary effects on the consumption-income ratio in most African countries .     

Purchasing Power Parity and the European single currency: Some new evidence

The effect of the single currency on the Purchasing Power Parity (PPP) hypothesis is examined in this study for the 15 EU countries, vis a vis the US dollar, before and after the advent of the euro. Standard as well as nonlinear unit root tests are employed on the time series dimension. Unit root tests reject PPP and the highest half-lives are observed after the introduction of the single currency. Panel unit root (Pesaran, 2007) and stationarity tests (Hadri and Kurozumi, 2008) that take into account cross-sectional dependence are also estimated. The results remain inconclusive as panel stationarity tests fail to support PPP whereas panel unit root tests fail to reject PPP for the whole sample and for the period before the introduction of the single currency.     

中国实际利率平价的KSS非线性单位根检验

中国一直在进行资本和金融项目的渐进改革,通常描述和刻画这一经济规律变化的是利率平价理论。由于近十几年限制我国利率平价的制度约束条件均得到缓解,所以,本文利用基于ESTAR结构的KSS非线性单位根检验分析法,并连同ADF和PP检验一起对我国实际利率平价进行了实证,检验结果表明,实际利率平价假说成立,并遵循非线性稳态过程,利率的非对称调整导致信贷市场和金融市场的信息不对称。这说明短期内实际利率的调整特征是平滑转移的,在长期内,双边国家均无法实施相对独立的货币政策。     

FURTHER EVIDENCE ON MEAN REVERSION IN THE AUSTRALIAN EXCHANGE RATE

In this paper we re‐examine the purchasing power parity (PPP) in Australia for the period February 1970 to April 2005 using an alternative method relative to the previous studies. We underlined large shocks due to depreciations that affected the Australian exchange rate, using outlier methodology. Once we adjusted the data of these outliers that had large, but either temporary or permanent effects on the series, our results show that there is no tendency for PPP in Australia to hold in the long run during this period.     

Do Energy Prices Affect U.S. Investor Sentiment?

The current literature has examined the effect of investor sentiment on energy prices, but no study ever has explored the validity of the reverse question. Therefore, this article explore whether energy prices (i.e., crude oil and natural gas prices) affect U.S. investor sentiment, using the methodology of quantile regression. The empirical results document that controlling for a number of U.S. macroeconomic and financial factors, there exists a statistically significant association between oil and natural gas prices and investor sentiment. However, only natural gas prices appear to retain their statistical significance over the majority of quantiles. These findings received robust support under alternative measures of the investor sentiment index.     

人民币汇率合理性判断--用平行数据单位根对人民币购买力平价的经验分析

本文讨论了人民币汇率是否合理、人民币是否应该升值的两个判断标准,采用四种新发展起来的平行数据单位根检验法,对1978年1月-2004年9月的人民币购买力平价进行了检验.检验的结果普遍支持了购买力平价,可以认为人民币汇率的长期基础是合理的.但我们认为由于汇率在当代存在着两重作用与二重性,现有汇率理论只能部分地解释汇率的决定.论文对汇率的两重作用与二重性进行了分析.     

Are business cycles stationary fluctuations around a deterministic trend? Empirical evidence from 79 developing countries

There is a large literature that tests the univariate time series properties of the real output series following the seminal work of Nelson and Plosser (1982). Whether or not real output is characterized by a unit root process has important implications. A unit root in real output, for instance, is inconsistent with the notion that business cycles are stationary fluctuations around a deterministic trend. In this paper, we investigate the univariate time series properties of real output for 79 developing countries using the conventional augmented Dickey and Fuller (1979) unit root test, the Zivot and Andrews’ (1992) one structural break unit root test, and the Lumsdaine and Papell (1997) two structural breaks unit root test. Our main finding is that, for 40 countries, real output is stationary around a trend. This indicates that business cycles are stationary fluctuations around a deterministic trend for only 51% of the developing countries in our sample.     

Revisiting purchasing power parity for East Asian countries using the rank test for nonlinear cointegration

This study applies a simple and powerful nonlinear rank test, proposed by Breitung (2001) to test the validity of long-run Purchasing Power Parity (PPP) in a sample of East Asian countries over the period March 1985–September 2008. The empirical results indicate that PPP holds for all of East Asian countries studied and the nominal exchange rate, domestic Consumer Price Index (CPI) and the US CPI are all linearly interrelated with the exception of China. Our results have important policy implications for these East Asian countries under study.     

Investigation of the nonlinear behaviour in real exchange rates in developing regions

This article examines whether the purchasing power parity (PPP) theory holds or not for the economies in different developing regions located in Africa, Asia and Latin America. In order to investigate this issue, a nonlinear panel unit root test is used to determine if some or all of the real exchange rates in a panel follow a stationary exponential smooth transition autoregressive process. By applying the nonlinear panel unit root test, our results demonstrate an empirical support for the theory of PPP for the economies in developing regions.     

The purchasing power parity puzzle is worse than you think

The ‘‘purchasing power parity puzzle’’ is the difficulty of reconciling very high short-term volatility of real exchange rates with very slow rates of mean reversion. The strongest evidence of slow mean reversion comes from least squares estimates of first-order autoregressive models of the long-horizon dollar-sterling real exchange rate. Using median-unbiased estimation methods, we show that these methods underestimate the half-lives of PPP deviations, and thus overestimate the speed of mean reversion. When the specification is amended to allow for serial correlation, the speed of mean reversion falls even further. This makes resolution of the purchasing power parity puzzle more problematic.First version received: May 2003/Final version received: July 2004We thank Lutz Kilian, James Lothian, Mark Taylor, and two anonymous referees for helpful comments and suggestions.     

Real interest rate parity in Asian countries: evidence from the quantile unit root test

This article studies the real interest rate parity (RIP) for several Asian countries. This is done by examining the stationarity in the real interest rate differentials (rids) with respect to the US using the quantile unit root test. Our results show that rids exhibits unit-root behaviours in the lower quantile levels, and mean reversion in the upper quantile levels. Furthermore, large positive shocks tend to induce strong mean reversion and the adjustment towards the long-run equilibrium level is faster as rids gets larger, with shorter half-lives in the extreme quantile levels.     

基于购买力平价的中国商业银行生产效率的国际比较

本文首次以购买力平价作为贷币换算系数,利用数据包络分析方法对我国商业银行与欧美发达国家的商业银行的生产效率进行了比较研究,精确计量了我国商业银行与发达国家商业银行的效率差距.研究结果证明:现阶段我国商业银行的生产效率平均只有欧美发达国家的最好的商业银行的四分之一,差距很大,存在着比较严重的投入过剩.     

THE REAL INTEREST RATE DIFFERENTIAL: INTERNATIONAL EVIDENCE BASED ON NON-LINEAR UNIT ROOT TESTS

This paper aims at testing international parity conditions by using non-linear unit root tests advocated by Kapetanios et al . (2003, KSS). Results from the KSS tests based on 17 countries (G7 and 10 Asian countries) overwhelmingly show that the adjustment of real interest rates towards real interest rate parity (RIP) follows a non-linear process except for the Taiwan, Hong Kong and Philippines relationships with both the USA and Japan. Overall, the empirical results are in favour of RIP using the USA and Japan as the centre countries but only if non-linearities are accounted for in the data-generating process. Our findings confirm that interest rate differentials, like the real exchange rates reported in recent literature, display a non-linear mean reversion process.