revisiting purchasing power parity for african countries with nonlinear panel unit root tests this study applies panel seemingly unrelated regressions sur kapetanios et al kapetanios shin snell kss surkss tests proposed by wu and lee 2009 to investigate the properties of long run purchasing power parity ppp in 15 african countries the empirical results from the univariate unit root and panel based unit root tests indicate that ppp does not hold for these 15 countries under study however panel surkss tests indicate that ppp is valid for four of these 15 countries these results have important policy implications for these 15 african countries under study

a parametrization of the auction design space abstract we present an extensive breakdown of the auction design space that captures the essential similarities and differences of many auction mechanisms in a format more descriptive and useful than simple taxonomies this parametrization serves as an organizational framework in which to classify work within the field and uncovers parameter combinations corresponding to novel mechanisms the structured characterization of auction rules can be exploited for the modular design of configurable auction servers it also facilitates the communication of auction rules to software agents enabling the automation of flexible market based negotiation journal of economic literature classification numbers c70 d44

nonlinear dynamics in deviations from the law of one price a broad based empirical study abstract in this paper we test empirically the validity of the law of one price using data for five major bilateral us dollar exchange rates and nine goods sectors during the recent floating exchange rate regime since the early 1970s using threshold autoregressive models we find strong evidence of nonlinear mean reversion in deviations from the law of one price with plausible convergence speeds consistent with theoretical arguments on international goods markets arbitrage under transactions costs and with an emerging strand of empirical literature these results contribute towards forming a consensus view in favor of discrete regime switching in deviations from the law of one price and the presence of differing nonzero transactions costs across a broad range of goods and countries

are asian real exchange rates stationary by applying the newly developed nonlinear stationary test advanced by kapetanios et al journal of econometrics 112 2003 359 in examining the stationary property of 11 asian real exchange rates this paper rejects unit root in 8 us dollar based and 6 japanese yen based rates whereas the augmented dickey fuller adf test has led to no rejection at all

bank lending policy credit scoring and the survival of loans to evaluate loan applicants banks increasingly use credit scoring models the objective of such models typically is to minimize default rates or the number of incorrectly classified loans thereby they fail to take into account that loans are multiperiod contracts for which reason it is important for banks not only to know if but also when a loan will default in this paper a bivariate tobit model with a variable censoring threshold and sample selection effects is estimated for 1 the decision to provide a loan or not and 2 the survival time of granted loans the model proves to be an effective tool to separate applicants with short and with long survival times the bank s loan provision process is shown to be inefficient loans are granted in a way that conflicts with both default risk minimization and survival time maximization there is thus no trade off between higher default risk and higher return in the lending policy

the black market exchange rate vs the official rate in testing ppp which rate fosters the adjustment process abstract in testing the purchasing power parity theory ppp researchers hardly pay attention to the speed with which the exchange rate adjusts to a change in relative prices in this paper we show that the speed of adjustment is faster when the black market exchange rate is used in testing the ppp as compared to the official exchange rate this could be another reason as to why central banks should unify the two rates

does ppp hold in african countries further evidence based on a highly dynamic non linear logistic unit root test with a view to investigating whether the purchasing power parity ppp theory holds true for selected african countries during the january 1980 december 2003 period we employ a rigorous highly dynamic non linear logistic unit root test as first advanced by leybourne et al 1998 which is considerably more powerful than those tests traditionally used compared with the rejection of the null of the unit root process for only one of the 22 countries under study when we use the traditional adf pp kpss np and the df gls unit root tests with the leybourne et al 1998 test we strongly reject the null of the unit root process for a surprising six of the 22 countries these empirical results clearly indicate that ppp holds true for these six countries namely the central african republic the cote d ivoire kenya madagascar uganda and lesotho

long run purchasing power parity with asymmetric adjustment further evidence from african countries this study applies threshold cointegration test advanced by enders and siklos 2001 to investigate the properties of asymmetric adjustment in long run purchasing power parity ppp in 22 selected african countries during the period of january 1980 to december 2003 although there is evidence of long run ppp for most african countries the adjustment mechanism is asymmetric these results have particularly important policy implications for african countries

a binary conflict ascending price bicap mechanism for the decentralized allocation of the right to use railroad tracks the questions posed for study are motivated by controversies over how sweden might change from a centralized system of railroad management to a decentralized system the central rail administration banverket will retain ownership and maintenance responsibility of the tracks but will sell access to the tracks to private firms the questions are about the mechanism that might accomplish this task parties to the controversy have claimed that the technical aspects of networks will as a matter of principle preclude the operation of any decentralized method this paper explores the properties of a mechanism developed as a challenge to that claim the mechanism is examined in the context of a testbed experimental environment that contains many potential problem causing elements in the tests performed the mechanism operated to efficiently allocate access to the network and it did so for behavioral reasons that are understandable in terms of theory the paper closes with suggestions for further study of environments that might present additional challenges to a mechanism

purchasing power parity with flexible fourier stationary test for central and eastern european countries this study applies stationary test with a fourier function proposed by enders and lee 2004 2009 to test the validity of long run purchasing power parity ppp to assess the nonstationary properties of the real exchange rate rer for seven central and eastern european countries ceecs we find that our approximation has higher power to detect u shaped breaks and smooth breaks than linear method if the true data generating process of exchange rate is in fact a stationary nonlinear process we examine the validity of ppp from the nonlinear point of view and provide robust evidence clearly indicating that the ppp holds true for all ceecs our findings point out their exchange rate adjustment is mean reversion towards ppp equilibrium values in a nonlinear way

purchasing power parity in less developed and transition economies a review paper abstract the concept of purchasing power parity ppp has been the subject of numerous studies many of which have been unable to prove conclusively this core principle of international finance although industrialized countries have received most of the attention studies that focus on less developed and transition economies have also attained mixed results this study surveys trends in this branch of the literature highlighting the econometric advances that have sought to solve this puzzle while pointing out that more needs to be done to address the reasons that might cause ppp not to hold

the inadequacy of linear autoregressive model for real exchange rates empirical evidence from asian economies utilizing the formal linearity test of luukkonen saikkonen and terasvirta biometrika 75 491 499 1998 as diagnostic tool the empirical finding suggests that the linear autoregressive ar model is inadequate in describing the real exchange rates behaviour of 11 asian economies it is noted that the conventional battery of diagnostic tests is capable of identifying the inadequacy of the linear model in only three of these series moreover the linearity nature of this behaviour has been formally rejected in favour of the non linear smooth transition autoregressive star model the finding of non linearity in the data generating process of these real exchange rates warrants that the use of linear framework in empirical modelling and statistical testing procedures in the field of exchange rates may lead to an inappropriate policy conclusions

a dominant strategy double auction a double auction mechanism that provides dominant strategies for both buyers and sellers is analyzed this mechanism satisfies the 1n convergence to efficiency of the buyer s bid double auction in addition the mechanism always produces full information first best prices the inefficiency arises because the least valuable profitable trade may be prohibited by the mechanism the mechanism has an oral implementation utilizing bid and asked prices

auction protocols for decentralized scheduling decentralized scheduling is the problem of allocating resources to alternative possible uses over time where competing uses are represented by autonomous agents market mechanisms use prices derived through distributing bidding protocols to determine schedules we investigate the existence of equilibrium prices for some general classes of scheduling problems the quality of equilibrium solutions and the behavior of an ascending auction mechanism and bidding protocol to remedy the potential nonexistence of price equilibria due to complementarities in preference we introduce additional markets in combinations of basic goods finally we consider direct revelation mechanisms and compare to the market based approach journal of economic literature classification numbers c62 c70 d44

allocating uncertain and unresponsive resources an experimental approach we identify an important class of economic problems that arise naturally in several applications the allocation of multiple resources when there are uncertainties in demand or supply unresponsive supplies no inventories and fixed capacities and significant demand indivisibilities rigidities examples of such problems include scheduling job shops airports or supercomputers zero inventory planning and the allocation and pricing of nasa s planned space station using experimental methods we show that the two most common organizations used to deal with this problem markets and administrative procedures can perform at very low efficiencies 60 65 efficiency in a seemingly robust example thus there is a need to design new mechanisms that more efficiently allocate resources in these environments we develop and analyze two mechanisms that arise naturally from auctions used to allocate single dimensional goods these new mechanisms involve computer assisted coordination made possible by the existence of networked computers both mechanisms significantly improve on the performance of administrative and market procedures

do real exchange rates follow a nonlinear mean reverting process in developing countries in an effort to fight relatively high inflation many developing countries try to manage their nominal exchange rates through official intervention in addition developing countries tend to have high transportation costs tariffs and nontariff barriers these factors are among the sources of generating nonlinearity in real exchange rates and hence some nonlinear adjustment toward purchasing power parity ppp in developing countries in this paper we employ monthly real effective exchange rate reer data of 88 developing countries and test the null of nonstationarity versus an alternative of linear stationarity by the means of a conventional unit root test and compare the results with those obtained from a new test in which the null is the same but the alternative hypothesis is nonlinear stationarity the latter test supports the ppp theory in more developing countries compared with the former test suggesting that nonlinear adjustment toward ppp in developing countries is an important phenomenon reported country characterizations indicate that reversion in reer occurs more often for high inflation countries and for countries with high flexibility in their exchange rates

long run purchasing power parity in the 1920s abstract this paper presents an empirical analysis of long run purchasing power parity ppp during the 1920s float using recently developed methodology on the cointegration of economic time series our results are generally supportive of ppp as a long run equilibrium condition on which exchange rates tended to converge over the period for dollar sterling however there is some evidence of a non stationary drift away from fundamentals during the last year or so before britain s return to the gold standard perhaps due to speculation our results also appear to reconcile some apparently conflicting evidence in the literature

do exchange rates follow a random walk process in middle eastern countries abstract in this note we employ the kpss test in addition to the adf test to determine whether the real effective exchange rates in middle eastern countries follow a random walk process or they are stationary while in most cases the kpss test supported the stationary of the real effective rates thus the ppp the adf test did not the failure to support the ppp by the adf test is said to be due to its low power

costly monitoring loan contracts and equilibrium credit rationing this paper develops a model with asymmetrically informed agents and costly monitoring of loan contracts where an equilibrium can exhibit credit rationing borrowers are identical ex ante but some receive loans and others do not in contrast to existing credit rationing theories rationing does not occur here due to inflexible prices adverse selection or moral hazard optimizing behaviour produces a standard debt contract in equilibrium the aggregate quantity of loans and equilibrium interest rates respond differently depending on whether there is rationing in equilibrium

real exchange rate behavior in the middle east a re examination abstract this letter extends recent work by bahmani oskooee bahmani oskooee m do exchange rates follow a random walk process in middle eastern countries economics letters 1998 58 339 344 on testing long run purchasing power parity for middle eastern countries during the post bretton woods period using multivariate nonlinear models strong support is provided for highly nonlinear reversion of real exchange rates toward a stable equilibrium for each country examined

multi item auctions a collection of items is to be distributed among several bidders and each bidder is to receive at most one item assuming that the bidders place some monetary value on each of the items it has been shown that there is a unique vector of equilibrium prices that is optimal in a suitable sense for the bidders in this paper we describe two dynamic auction mechanisms one achieves this equilibrium and the other approximates it to any desired degree of accuracy

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

bilateral trade with the sealed bid k double auction existence and efficiency for k in the unit interval the k double auction determines the terms of trade when a buyer and a seller negotiate transfer of an item the buyer submits a bid b and the seller submits an offer s trade occurs if b exceeds s at price kb 1 k s we model trade as a bayesian game in which each trader privately knows his reservation value but only has beliefs about the other trader s value existence of a multiplicity of equilibria is proven for a class of trader s beliefs for generic beliefs however these equilibria are shown to be ex ante inefficient

characterizing effective trading strategies insights from a computerized double auction tournament abstract this paper presents a comparative analysis of 30 computer trading programs that participated in a double auction tournament held at the santa fe institute in 1990 and 1991 our objective is to characterize the form of effective trading strategies in double auction markets we find that a simple rule of thumb is a highly effective and robust performer over a wide range of trading environments significantly outperforming more complex algorithms that use statistically based predictions of future transaction prices explicit optimizing principles and sophisticated learning algorithms