In recent decennaries, a bulk of documents about the buying power para ( PPP ) have been published. The writers of the documents investigate PPP in different states and continents over different periods by utilizing different methods. They besides use different currencies, US dollar, British lb, Euro, Australian dollar and Nipponese Yen etc, as the base currencies and different indices such as CPI, WPI and TPI to prove. In add-on, a batch of attacks are used. They are cointegration attack, ADF trial, panel unit root trial, etc. Hence, different decisions are drawn and the consequences are diverse.
PPP in Asia Pacific Countries
Most economic experts argue that PPP holds in the long tally for Asia Pacific Countries. Lee ( 1999, cited in Ahmad et Al. 2002 ) tests the PPP by utilizing the generalised mistake rectification theoretical account and finds that PPP holds in the long tally for 13 Asia Pacific states. The long tally PPP exits between Australia and other 7 Asia Pacific states except Indonesia by utilizing both CPI and WPI, and the informations used are quarterly from 1971 to 1998 ( Bhati and McCrae, 2004 ) . The Australian dollar is considered as “ basal currency ” . The unit root trial ( The ADF trial ) and the cointegration method are used by Bhati and McCrae ( 2004 ) to look into the stationary of variables and trial for a relationship between the nominal exchange rate and the ratio of the degrees of the monetary value in this survey. Through trials, Bhati and McCrae ( 2004 ) argue that it is hard to state which 1 is better between CPI and WPI.
PPP in Africa
Kargo ( 2003 ) used ADF trial, multivatiate cointegration technique and mistake rectification patterning. In add-on, the cointegration method is more often used to analyze the relation among econometric variables ( Kargo, 2003 ) . Furthermore, error rectification modeling is utilized to gauge the accommodation velocity towards the equilibrium in each state with a individual cointegration relationship ( Kargo, 2003 ) . The informations used are the one-year information for black market nominal exchange rates and CPI in 30 African states which covering 1960-97 ( Kargo, 2003 ) . Kargo ( 2003 ) examines whether the long-term PPP is through empirical observation supported in Africa, and finally finds that PPP is overpoweringly supported in Africa and PPP could be used as a utile usher to finding exchange rate and formulating policy in the states of Africa. The information, econometric attacks and the clip series under probe are reflected by the consequences on PPP ( Kargo, 2003 ) .
PPP in Central and Eastern European states
Baharumshah and Borsic ( 2008 ) look into whether the PPP is valid for 13 CEEC in passage by utilizing SURADF method. The monthly informations for nominal exchange rates and CPI used are from January 1994 to December 2005 ( Baharumshah and Borsic, 2008 ) . Baharumshah and Borsic ( 2008 ) widen the clip period due to a ample grasp which leads to the market exchange rate nearing the rate given by PPP. The USD and EUR are taken as base currency to build the existent exchange rates ( RERs ) . The ground why EUR is used is that big investing in some of the 13 states ( Baharumshah and Borsic, 2008 ) .
Baharumshah and Borsic ( 2008 ) find that the PPP relationship holds in 7 states for the USD-based rates and 6 states for EUR-based rates. Additionally, Baharumshah and Borsic ( 2008 ) say “ PPP holds better for states more unfastened to merchandise because trade barriers hinder international arbitrage. Passage states with higher rising prices rates and volatile exchange rates governments are non supportive of PPP ” .
Taylor and Sarno ( 1998, cited in Baharumshah and Borsic 2008 ) argue “ The chief booby trap of panel unit root trials is that a rejection of the joint unit root hypothesis could be driven by a few stationary series and the full panel might be concluded as stationary ” . The clip period is besides extended to supply recent informations to beef up the persuasive power of the survey ( Baharumshah and Borsic, 2008 ) .
PPP in European states
Most documents prefer look into the cogency of PPP in developed states particularly the European states to that of developing states. Due to the geographic propinquity and less official limitations, it is easy to happen PPP in European states ( Jenkins, 2004 ) . PPP holds in developed states with low volatility of nominal exchange rate ( Alba and Papell, 2005 ) . Alba and Papell ( 2007, cited in Cheng et al 2009 ) find that PPP has a inclination to keep for European states. The cointegration method has been the standard method to prove whether the long tally PPP holds in European states ( Engle and Granger, 1987, cited in Bleaney 1991 ) . Bleaney ( 1991 ) argue that WPI is preferred to CPI due to WPI includes an of import component of non-tradables and represents end product instead input monetary values.
Cheng et Al. ( 2009 ) use the ADF trial, the KPSS unit root trial and the unit root trial developed by Zivot and Andrews ( 1992, cited in Cheng et al 2009 ) to look into the cogency of PPP for 72 states. They use monthly CPI and US dollar as the base currency and happen that PPP holds in 40 of 72 states. Furthermore, Cheng et Al. ( 2009 ) besides argue that it is more likely to happen PPP for European states, but it is less likely to happen PPP for Asiatic states.
PPP in Latin American states
Alves et Al. ( 2001 ) look into the PPP in Brazil utilizing fractional cointegration analysis. The Results they get is that the absolute PPP does non keep but the comparative PPP is supported in the long tally in Brazil ( Alves et al, 2001 ) . Harmonizing to Alves et Al. ( 2001 ) , the jobs of the monetary value indices and the exchange rate uses by the authorities could do the failure of the absolute PPP. Alba and Papell ( 2007, cited in Cheng et Al. 2008 ) find that PPP is supported in Latin American states. Cheng et Al. ( 2008 ) examine PPP for 61 states by utilizing the panel cointegration attack and happen that PPP is stronger for Latin American states and state hazard might impact PPP. In add-on, state hazard is defined in footings of political, economic and fiscal elements ( Cheng et al, 2008 ) .
Alves et Al. ( 2001 ) argue PPP has been against several jobs so that PPP has been criticized, for illustration, goods transacted in the international market are similar might be merely of cogency for some goods, such as trade goods, but non for a big portion.
PPP in Developing states
Harmonizing to Ahmad et Al. ( 2002 ) , PPP does non keep in developing states by utilizing ADF and Philips-Perron. Through the generalized error-correction theoretical account, Ahmad et Al. ( 2002 ) conclude that PPP holds in the long tally for nine of the 11 developing states. In add-on, the limitations of the unit root trials prevent from happening grounds to back up PPP ( Ahmad et al. , 2002 ) . Ahmad et Al. ( 2002 ) suggest that the handiness of informations could do the survey more executable. Limitation of exchange rate motions that impede the PPP to keep might be showed by volatility of low nominal exchange rate ( Alba and Papell, 2005 ) .
PPP in Asiatic states
Lee et Al. ( 2009 ) look into the cogency of PPP in 6 Asiatic states utilizing the Breitung rank trials. Korea and Singapore are included. Differently, most surveies use US dollar or Euro as base currency but Lee et Al. ( 2009 ) use Japan Yen as the base currency. Through trials, the long-term PPP is supportive in 6 Asiatic states under survey ( Lee et al, 2009 ) .
Factors that influence PPP
Alves et Al. ( 2001 ) argue that the PPP is by and large violated in the short tally due to the stickiness of monetary value and the costs of accommodation. However, the divergence from PPP has a inclination to vanish and the existent exchange rate becomes to equilibrium ( Alves et al, 2001 ) . Besides, Alves et Al. ( 2001 ) indicate that a long period of observations is required to analyze the long tally PPP. Kargbo ( 2004 ) suggests that it is utile to increase the sample size when analyzing the unit roots. Due to the deficiency of power of unit root trials in little samples, it leads to the failure to happen PPP ( Alba and Papell, 2005 ) . Jenkins ( 2004 ) indicates that PPP consequences are sensitive to the base currency.
Climate, oil monetary value, trade decrease, instability of political relations and wars could do PPP unstable ( Kargbo, 2004 ) . For illustration, there are relationship between periods of political instability and rising prices, depreciation of domestic currency and addition of monetary value in Africa ( Kargbo, 2004 ) .
Carlsson et Al. ( 2007 ) find that possible mechanisms such as differences in monetary value indices between states, measurement mistakes, costs of conveyance or differential productiveness dazes could do a failure of PPP.
In add-on, Cheng et Al. ( 2009 ) reveal that the cogency of PPP additions with the volatility of nominal exchange rate and decreases with rising prices rate utilizing the probit arrested development. Cheng et Al. ( 2008 ) besides suggest that due to sticky nominal exchange rates, the direction of nominal exchange rates and trade barriers could hinder PPP to be reached. Therefore, Alba and Papell ( 2007, cited in Cheng et Al. 2008 ) say that PPP may be supported in developed states with stable nominal exchange rate.
Furthermore, Alba and Papell ( 2007, cited in Cheng et Al. 2009 ) find that PPP is stronger for states with a shorter distance from the US, less limitations in trade, lower rising prices rates, growing rates of per capita existent GDP more similar to the US, and have moderate volatility of exchange rate.
Harmonizing to Cheng et Al. ( 2009 ) , divergences from PPP could be caused by real-world imperfectnesss ; states features such as trade openness, rising prices rate, volatility of exchange rate, geographical distance and growing rate of per capita existent GDP might impact the PPP.
Advantages of the methods
There are assorted methods for us to look into the PPP. Furthermore, different methods have different advantages. The ADF ( Dickey and Fuller, 1979, 1981 cited in Ahmad 2002 ) trial could be used to happen the grounds of PPP. The ADF trial has become the most standard popular attack to look intoing the stationary of the existent exchange rate ( Cheng et al, 2009 ) .
The Johansen cointegration process is widely used to analyzing economic informations. Due to Johansen ‘s multivariate cointegration technique could take the mistake construction of the information processes into history, it allows for interactions in the finding of the relevant variables ( Kargbo, 2004 ) .
Harmonizing to Cheng et Al. ( 2008 ) , unit root trials and cointegration method are normally used to prove PPP, and the advantage of cointegration trial for PPP is that the limitation of proportionality and symmetricalness imposed by unit root trials of existent exchange rates could be relaxed. However, the empirical consequences from unit root trial and cointegration trial, such as the ADF trial and Johansen ‘ s upper limit likeliness attacks provide PPP with small support ( Froot and Rogoff 1995, cited in Cheng et al 2008 ) . Cheng et Al. ( 2008 ) explain “ the failure to reject the nothing of unit root and the nothing of no cointegration is little sample size ” .
Panel methods take the fluctuation across states and clip into history so that it could be used to increase power ( Alba and Papell, 2005 ) . Panel unit root trials are a popular attack to proving the stationarity of existent exchange rate, and the panel informations method could beef up the power because of the big sample size ( Cheng et al, 2009 ) . Harmonizing to Cheng et Al. ( 2009 ) , probit theoretical account could find which states features are related to PPP and command the effects of possible mutualities between states features at the same clip.
Disadvantages of the methods
Although different methods to prove PPP have different advantages, they still have some failings. The traditional ADF and Phillips-Perron trial impose limitations that make it difficult to observe the grounds of PPP ( Ahmad, 2002 ) . Cointegration method does non prove the consequence and cause relationship between two variables ( Bhati and McCrae, 2004 ) . Through analysis, Cheng et Al. ( 2009 ) find that the nothing of unit root at the traditional degree for 5 states harmonizing to ADF trial, hence, ADF trial has low power to back up PPP.
Panel unit root trials are widely used to analyze the stationarity of existent exchange rate. However, these trials could non supply any information for each constituent state ( Cheng et al, 2009 ) .