Unit Roots and Structural Breaks: A Survey of the Literature

Since Perron (1989) the time series literature has emphasised the importance of testing for structural breaks in typical economic data sets and pronounced the implications of structural breaks when testing for unit root processes. In this paper we survey recent developments in testing for unit roots taking account of possible structural breaks. In doing so we discuss the distinction between taking structural break dates as exogenously determined, an approach initially adopted in the literature, and endogenously testing break dates. That is, we differentiate between testing for breaks when the break date is known and when it is assumed to be unknown. Also important is the distinction between discrete breaks and gradual breaks. Additionally we describe tests for both single and multiple breaks and discuss some of the pitfalls of the latter.

Common factors of the exchange risk premium in emerging European markets

Existing empirical evidence suggests that the Uncovered Interest Rate Parity (UIRP) condition may not hold due to an exchange risk premium. For a panel data set of eleven emerging European economies we decompose this exchange risk premium into an idiosyncratic (country-specific) element and a common factor using a principal components approach. We present evidence of stationary idiosyncratic and common factors. This result leads to the conclusion of a stationary risk premium for these countries, which is consistent with previous studies often documenting a stationary premium in developed countries. Furthermore, we report that the variation in the premium is largely attributable to a common factor influenced by economic developments in the United States.Uncovered Interest Rate Parity, Emerging Economies, Exchange Risk Premiums, Common Factors

Structural Breaks in the Real Exchange Rate and Real Interest Rate Relationship

In this paper we empirically examine the relationship between the real exchange rate and real interest rate differentials using recent econometric methods robust to potential structural breaks. Generally, our study provides evidence of this relationship in the long-run context. More specifically, we first focus on the UK-US relationship, and interestingly find limited evidence of this long-run relationship using traditional methods. But when an approach robust to endogenously determined structural breaks is employed, we find evidence that the real interest rate differential is an important determinant of the real exchange rate. Secondly, in order to investigate the relevance of structural shifts in a more global context, we carry out multiple country analysis. While providing evidence of this long-run relationship, European data suggest that the presence of structural breaks is not very common across countries and is indeed country-specific.Real exchange rate; real interest rate differential; nonstationarity; endogenously determined structural breaks; trace tests

Euro Area Inflation: Aggregation Bias and Convergence

EMU monetary policy targets aggregate Euro Area inflation. Concerns are growing that a focus on aggregate inflation may cause national inflation rates to diverge. While different explanations for diverging aggregate Euro Area inflation have been brought forward, the very impact of aggregation on divergence has however not been studied. We find a striking difference in convergence depending on the level of aggregation. While aggregate national inflation rates are diverging, disaggregate inflation rates are converging. We find that aggregation appears to bias evidence towards non-convergence. Our results are consistent with prominent theoretical and empirical evidence on aggregation biasEuro Area Inflation; Aggregation Bias; Convergence

International capital flows to emerging and developing countries: national and global determinants

This paper examines international capital flows to emerging and developing countries. We assess whether commonalities exist, the permanence of shocks to commonalities and their determinants. Also, we consider individual country coherence with global capital flows and we measure the extent of co-movements in the volatility of capital flows. Our results suggest there are commonalities in capital inflows, although aggregate or disaggregate capital flows respond differently to shocks. We find that the US long run real interest rate is an important determinant of global capital flows, and real commodity prices are relevant but to a lesser extent. We also find a role for human capital in explaining why some countries can successfully ride the wave of financial globalisation.Capital Flows; Emerging Markets; Developing Countries; Global Factors

Common and idiosyncratic factors of the exchange risk premium in emerging European markets

Existing empirical evidence suggests that the Uncovered Interest Rate Parity (UIRP) condition may not hold due to an exchange risk premium. For a panel data set of eleven emerging European economies we decompose this exchange risk premium into an idiosyncratic (country-specific) elements and a common factor using a principal components approach. We present evidence of a stationary idiosyncratic component and nonstationary common factor. This result leads to the conclusion of a nonstationary risk premium for these countries and a violation of the UIRP in the long-run, which is in contrast to previous studies often documenting a stationary premium in developed countries. Furthermore, we report that the variation in the premium is largely attributable to a common factor influenced by economic developments in the United States.Uncovered Interest Rate Parity, Emerging Economies, Exchange Risk Premiums, Common Factors

Unit Roots in Inflation and Aggregation Bias

In this paper, we examine whether UK inflation is characterized by aggregation bias using three sets of increasingly disaggregated inflation data and a battery of univariate and panel unit root tests. Our results support the existence of aggregation bias since while the unit root hypothesis cannot be rejected for aggregate inflation, it can be rejected for some of its sectoral components, with the rejection frequencies increasing when we use more disaggregate data. Results from structural break analysis indicate that monetary policy shifts are the main factor behind breaks in UK inflation. The panel results typically indicate that when sectoral inflation rates are pooled the unit root hypothesis can be rejected. Our results have important implications for applied econometric analysis, macroeconomic theory and for the conduct of monetary policy.Inflation, Unit Root, Disaggregation, Structural Breaks, Panel Data

Panel Estimation of the Impact of Uncertainty on Investment in the Industrial Countries

There is growing interest in economic uncertainty and its long run impact on investment. In previous work the authors established clear evidence of the negative impact of exchange rate uncertainty on investment in the G7, measured using a GARCH approach, and Pooled Mean Group Panel Estimation. In this paper we assess the impact on investment of temporary and permanent components of exchange rate uncertainty derived using a components GARCH model. For a poolable subsample of EU countries, results suggest that it is the transitory and not the permanent component which adversely affects investment.investment, uncertainty, exchange rates, non stationary panel estimation

Convergence in TFP among Italian Regions - Panel Unit Roots with Heterogeneity and Cross Sectional Dependence

This paper performs a number of tests to estimate convergence in total factor productivity (TFP) among Italian regions during the period 1970-2001. We generate the regional TFP series using growth accounting methodologies, and then apply a range of panel unit root tests to analyse the process of convergence. We extend the existing literature by incorporating three main improvements. Firstly, we control for the heterogeneity arising from the different economic structure of each region. Secondly, we account for the cross-sectional dependence due to common shocks or spillovers among different regions at the same time. Finally, we look for clubs of convergence using tests of poolability both on economic and statistical grounds.