detecting periodically collapsing bubbles a markov switching unit root test this paper addresses the problem of testing for the presence of a stochastic bubble in a time series in the case that the bubble is periodically collapsing so that the asset price keeps returning to the level implied by the market fundamentals as this is essentially a problem of identifying the collapsing periods from the expanding ones we propose using a generalization of the dickey fuller test procedure which makes use of the class of markov regime switching models the potential of the new methodology is illustrated via simulation and an empirical example is given copyright 1999 john wiley sons ltd

deviations from purchasing power parity in the long run this paper demonstrates that deviations from purchasing power parity reveal a remarkable and possibly startling consistency with martingale behavior during both fixed and flexible rate periods for a wide variety of countries and in both monthly and annual data since this pattern appears to be much more general than one would expect on the basis of models founded on international commodity arbitrage the paper proposes an alternative explanation which instead relies on financial arbitrage in bonds as the underlying mechanism this paper will demonstrate that deviations from purchasing power parity ppp reveal a remarkable and possibly startling consistency with martingale behavior during both fixed and flexible exchange rate periods for a wide variety of countries and in both monthly and annual data this pattern appears to be much more general than one would expect on the basis of models founded on international commodity arbitrage the paper therefore proposes an alternative explanation which does not presuppose free trade in goods but which instead relies on financial arbitrage in bonds as the underlying mechanism the major implication of the theory and the results is that ppp is as likely to be violated in the long as in the short run as an empirical matter deviations from ppp can be observed for most currencies at any instant see kravis et al 21 stockman 37 and genberg 15 among others these deviations are typically both cumulative and persistent the real exchange rate can remain on either side of parity for lengthy but variable time intervals of a year or more as a consequence the current consensus shared

the singer prebisch hypothesis a statistical evaluation the statistical objections raised against the singer prebisch thesis regarding the secular decline in the terms of trade of primary products in relation to manufactures do not have as sound a basis as is generally supposed they have on a priori grounds the projection of that historical experience into the post war years as made by h w singer and r prebisch also holds good until the oil crisis years of the 1970s it would hold true up to 1983 if oil and opec are exc luded as a special case with the decline in the terms of trade of primary products the trading terms of the developing region vis a vis the developed one also deteriorated in view of increasing manufacture exports by the developing region it is doubtful how far the two terms of trade indexes will move in the same direction copyright 1986 by oxford university press

testing for ppp the erratic behaviour of unit root tests abstract in this article we argue that the type of stationarity exhibited by the real exchange rate cannot be accommodated by the fixed parameter autoregressive homoscedastic models normally employed in the literature using a dataset including 39 countries and spanning a period of up to two centuries we analyse the behaviour of both wpi and cpi based measures of the real exchange rate in particular we compute a recursive t statistic and show that it has an erratic behaviour suggesting the presence of endemic instability it appears that the type of non stationarity present in the data is more complex than the unit root one this explains the contradictory results of previous studies using standard unit root tests for establishing whether ppp holds

real exchange rates in the short medium and long run abstract this paper uses long horizon autocorrelations and variance ratio statistics to test for long term mean reversion in real exchange rates unlike most previous tests of this hypothesis the tests do reject a random walk for monthly data in the post bretton woods era however the statistics indicate that positively correlated innovations rather than mean reversion are the source of the rejection tests using annual data for the twentieth century also reject the random walk in this case however the rejection can be attributed to mean reversion and confirms that ppp is a long term phenomenon

a triangular purchasing power parity hypothesis we propose a triangular purchasing power parity ppp analytical framework which is theoretically justified and empirically validated the mechanisms and channels through which a seemingly mystery relationship emerges are deliberated and examined which renders significant implications to international monetary economics finance and business the de facto peg of the rmb to the us dollar together with trade activities and arrangements causes a triangular ppp effect that the dollar euro exchange rate is not a function of the relative prices in the us and euroland instead it becomes a function of the relative prices in the people s republic of china prc and euroland the results are supportive of triangular ppp in a three economy world of the us euroland and prc

tests for symmetric and asymmetric nonlinear mean reversion in real exchange rates new tests based on smooth transition autoregressive models for mean reversion in time series of real exchange rates are proposed one test forces mean reversion to be symmetric about the integrated process central case while the other permits asymmetry the tests are applied to monthly series of seventeen real exchange rates against the u s dollar and fourteen against the deutsche mark they reveal stronger evidence against the unit root null hypothesis than does the usual dickey fuller test

long run trends in 26 primary commodity prices abstract this paper uses time series techniques to re examine the prebisch singer hypothesis that there has been a secular deterioration in primary commodity prices in terms of manufactured goods instead of using price indices it considers 26 individual commodity prices over the period 1900 1983 this avoids possible aggregation and interpretation problems associated with the use of aggregate indices the study finds that 16 of the 26 prices are trendless five have statistically significant negative trends the remaining five have positive trends it concludes that the prebisch singer hypothesis should certainly not be considered a universal phenomenon or stylized fact

evidence of purchasing power parity for the floating regime period abstract this paper investigates the ppp hypothesis within industrialized countries for the post bretton woods period via two panel unit root tests the df gls sur and the adf sur tests respectively developed by lopez a panel unit root with good power in small samples econometric reviews in press and levin et al 2002 unit root tests in panel data asymptotic and finite sample properties journal of econometrics 108 1 1 24 both approaches allow for data specific serial and contemporaneous correlation while both tests provide ppp evidence for the post 1973 period the more powerful df gls sur test demonstrates consistently stronger results especially for the 1973 1998 period

real exchange rate behavior the recent float from the perspective of the past two centuries using annual data spanning two centuries for dollar sterling and franc sterling real exchange rates we find strong evidence of mean reverting real exchange rate behavior using simple stationary autoregressive models estimated on prefloat data we easily outperform nonstationary real exchange rate models in dynamic forecasting exercises over the recent float such stationary univariate equations explain 60 80 percent of the in sample variation in real exchange rates although the degree of short run persistence may be high the econometric estimates imply a half life of shocks to the real exchange rate of about 6 years for dollar sterling and a little under 3 years for franc sterling

state of the art unit root tests and purchasing power parity although the question of whether purchasing power parity ppp holds in the long run has been extensively studied the answer is still controversial some of the strongest evidence is provided by taylor the review of economics and statistics 84 2002 139 150 who concludes that long run ppp held over the 20th century we argue that this conclusion is quite sensitive to the use of sub optimal lag selection in unit root tests using superior lag selection methods we find that long run ppp held for the real exchange rates of only 9 out of the 16 industrialized countries in taylor s sample with the u s dollar as the base currency

does purchasing power parity hold sometimes regime switching in real exchange rates standard unit root tests are not very powerful in drawing conclusions regarding the validity of purchasing power parity ppp rather than asking whether ppp holds throughout the whole sample period we examine in this study if ppp holds sometimes by employing hamilton type 1989 markov regime switching models when at least one of multiple regimes is stationary ppp holds locally within the regime there are indeed various reasons that we should expect that the persistence of real exchange rates changes over time employing five real exchange rates spanning more than 100 years we find herein strong evidence that the strength of ppp varies during the sample periods and that there exist stationary regimes in which ppp holds throughout the article we also make comparisons to previous markov regime switching estimation results by kanas 2006 on the same data series the new markov switching model selection criterion of smith et al 2006 which is devised especially for discriminating markov regime s

nonlinear mean reversion to purchasing power parity exponential smooth transition autoregressive models and stochastic unit root processes nonlinear exponential smooth transition autoregressive estar models are recently very popular in modelling the deviation from purchasing power parity this article shows that there is a close relation between the estar models estimated in taylor et al 2001 and stochastic unit root stur processes of granger and swanson 1997 and mccabe and tremayne 1995 also for a post bretton woods sample period the real exchange rates from four major countries are tested if they are better described as i 1 estar or stur processes

some new stylized facts of floating exchange rates abstract this paper re examines real exchange rate behavior of oecd currencies under the current float using the more extensive dataset that an additional decade s worth of experience has made available what emerges is a new set of stylized facts which suggest that the problems of the current float were not as commonly believed generic to that system but in fact rather specific being largely confined to one sub period the early and mid 1980s and one currency the us dollar this dollar behavior ranks as one of the important puzzles of the past 25 years

ex post regret and the decentralized sharing of information abstract firms reveal private information about the value of investment through their investment decisions as a consequence they may have ex post regret once they see other firms investments we define a notion of rational expectations equilibrium for games which imposes a no regret property in this equilibrium all firms make the same investment decision but despite the absence of ex post regret the investment herd can be inefficient in addition equilibrium might not exist we introduce a notion of probabilistic existence and identify conditions under which if the number of firms is large enough information comes out so that investment herds are first best efficient with high probability and equilibrium exists with high probability journal of economic literatureclassification numbers c7 d8

purchasing power parity and markov regime switching we revisit the evidence on ppp in the twentieth century allowing for markov regime switching in the adf regression using lopez et al s 2005 extension of taylor s 2002 original data set our results are 1 for most countries there are periods over which the real exchange rate is stationary and ppp holds and periods over which the real exchange rate is non stationary and ppp does not hold namely regime dependent stationarity thus real exchange rate stationarity is a stochastic event itself 2 the probability that the real exchange rate is stationary is less than 50 for most countries 3 there is evidence of non stationarity during both the bretton woods and the recent float periods for the majority countries the comparative performance of ppp is slightly better during bretton woods than the recent float

the terms of trade experience of britain since the nineteenth century the terms of trade of britain exhibited a declining trend in the first half of the nineteenth century but after two decades of transitional confusion they started to move upwards the explanation lies in the fact that the reversal of the trend corresponded to a change in the structure of british export trade from the dominance of traditional textile products towards other manufactures unlike the traditional textile products these other manufactures had little indigenous counterpart in the agrarian countries with which britain had expanding trade relations so while cost reduction through technical progress led to a rapid fall in the prices of cotton textiles under stiff competition at home and abroad producers in the newer sectors did not have to respond much to this type of cost reducing technical progress that spread to these sectors in the latter period thus as prebisch and singer argued the classical scheme of distribution of the gains from technical progress through trade that was supposed to

real exchange rates and switching regimes abstract we suggest that the real exchange rate between the major currencies in the post bretton woods period can be described by a stationary 2 state markov switching ar 1 model based on the forecast performance we find that this model outperforms two competing models where the real exchange rate is nonstationary we also find that the existence of different regimes as in the markov switching model is consistent with the common finding of unit roots in real exchange rates

business cycles and the exchange rate system some international evidence this paper investigates the differences in time series behavior of key economic aggregates under alternative exchange rate systems we use a postwar sample of 49 countries to compare the behavior of output consumption trade flows government consumption spending and real exchange rates under alternative exchange rate systems pegged floating and cooperative systems such as the ems we then examine evidence from two particular episodes involving canada and ireland of changes in the exchange rate system aside from greater variability of real exchange rates under flexible than under pegged nominal exchange rate systems we find little evidence of systematic differences in the behavior of macroeconomic aggregates or international trade flows under alternative exchange rate systems these results are of interest because a large class of theoretical models implies that the nominal exchange rate system has important effects on a number of macroeconomic quantities

nonlinear mean reversion in real exchange rates abstract this paper modifies a unit root test procedure in the nonlinear star framework recently advanced by kapetanios et al journal of econometrics 2001 in press using a detrending methodology suggested by schmidt and phillips oxford bulletin of economics and statistics 54 1992 257 we derive an alternative unit root test and apply it to the bilateral real exchange rates for the g7 countries we find that the use of our test is able to uncover evidence of nonlinear mean reversion for most cases whereas the standard dickey fuller test based on the linear model cannot

the long run behavior of the relative price of primary commodities statistical evidence and policy implications abstract this paper is concerned with both the statistical and policy issues surrounding the long run behavior of the ratio of primary commodities prices to those of manufactured goods seen as a measure of the barter terms of trade between primary producers and the producers of manufacturers the statistical evidence reported is found to offer support for the secular deterioration hypothesis the policy implications of this finding for less developed countries are explored

regime non stationarity in the us uk real exchange rate abstract using a markov switching extension of the adf regression we find evidence that the us uk real exchange rate is stationary in periods when it is in a low volatility regime and nonstationary when it is in a high volatility regime

transactions costs and nonlinear adjustment in real exchange rates an empirical investigation eolquilibrium models of real exchange rate determination in the presence of transactions costs imply a nonlinear adjustment process toward purchasing power parity ppp conventional cointegration tests which ignore the effect of transactions costs may be biased against the long run ppp hypothesis our results using both monthly data for the interwar period and annual data spanning two centuries clearly reject the linear framework in favor of an exponential smooth transition autoregressive process the systematic pattern in the estimates of the nonlinear models provides strong evidence of mean reverting behavior for ppp deviations and helps explain the mixed results of previous studies