A Simple Panel Unit Root Test in the Presence of Cross Section Dependence

A number of panel unit root tests that allow for cross section dependence have been proposed in the literature, notably by Bai and Ng (2002), Moon and Perron (2003) and Phillips and Sul (2002) who use orthogonalization type procedures to asymptotically eliminate the cross dependence of the series. In this paper we propose a simple alternative test where the standard DF (or ADF) regressions are augmented with the cross section averages of lagged levels and first-differences of the individual series. A truncated version of the CADF statistics is also considered. New asymptotic results are obtained both for the individual CADF statistics and their simple averages. It is shown that the CADFi statistics are asymptotically similar and do not depend on the factor loadings under joint asymptotics where N (cross section dimension) and T (time series dimension) ? 8, such that N/T? k, where k is a fixed finite non-zero constant. But they are asymptotically correlated due to their dependence on the common factor. Despite thi

Market efficiency today

This CFS Working Paper has been presented at the CFSsymposium "Market Efficiency Today" held in Frankfurt/Main on October 6, 2005. In 2004 the Center for Financial Studies (CFS) in cooperation with the Johann Wolfgang Goethe University, Frankfurt/Main established an international academic prize, which is to be known as The Deutsche Bank Prize in Financial Economics. The prize will honor an internationally renowned researcher who has excelled through influential contributions to research in the fields of finance and money and macroeconomics, and whose work has lead to practice and policy-relevant results. The Deutsche Bank Prize in Financial Economics has been awarded for the first time in October 2005. The prize, sponsored by the Stiftungsfonds Deutsche Bank im Stifterverband für die Deutsche Wissenschaft, carries a cash award of € 50,000. The prize will be awarded every two years and the prize holder will be appointed a "Distinguished Fellow" of the CFS. The role of media partner for the Deutsche Bank Prize in Financial Economics is to be filled by the internationally renowned publication, The Economist and the Handelsblatt, the leading German-language financial and business newspaper

Estimation and Inference in Large Heterogeneous Panels with a Multifactor Error Structure

This paper presents a new approach to estimation and inference in panel data models with a multifactor error structure where the unobserved common factors are (possibly) correlated with exogenously given individual-specific regressors, and the factor loadings differ over the cross section units. The basic idea behind the proposed estimation procedure is to filter the individual-specific regressors by means of (weighted) cross-section aggregates such that asymptotically as the cross-section dimension (N) tends to infinity the differential effects of unobserved common factors are eliminated. The estimation procedure has the advantage that it can be computed by OLS applied to an auxiliary regression where the observed regressors are augmented by (weighted) cross sectional averages of the dependent variable and the individual specific regressors. Two different but related problems are addressed: one that concerns the coefficients of the individual-specific regressors, and the other that focusses on the mean of the individual coefficients assumed random. In both cases appropriate estimators, referred to as common correlated effects (CCE) estimators, are proposed and their asymptotic distribution as N ¨ ‡, with T (the time-series dimension) fixed or as N and T¨ ‡ (jointly) are derived under different regularity conditions. One important feature of the proposed CCE mean group (CCEMG) estimator is its invariance to the (unknown but fixed) number of unobserved common factors as N and T¨ ‡ (jointly). The small sample properties of the various pooled estimators are investigated by Monte Carlo experiments that confirm the theoretical derivations and show that the pooled estimators have generally satisfactory small sample properties even for relatively small values of N and T.cross section dependence, large panels, common correlated effects, heterogeneity, estimation and inference

Online control of AC/AC converter based SHEPWM technique

Conventional online control of AC/AC converter controlled by the selective harmonic elimination pulse width modulation technique (SHEPWM) is based on storing the offline calculated switching angle values in a form of lookup table. Then the required switching pattern of certain modulation index (M) is searched through the lookup table. This methodology suffers from limited system flexibility. This paper introduces a novel implementation scheme based on real-time calculation of the required SHEPWM switching pattern with linear control of the fundamental voltage component magnitude based on curve fitting technique for the exact switching angle trajectories. The accuracy of the derived polynomials is evaluated by calculating converter performance parameters using the approximated switching angles solutions obtained from the introduced method and the exact switching angles solutions. Detail of the introduced methodology is presented. Simulation and experimental results have been carried out to confirm the validity of the introduced algorithm

Forecast Uncertainties in Macroeconometric Modelling: An Application to the UK Economy

This paper argues that probability forecasts convey information on the uncertainties that surround macroeconomic forecasts in a manner which is straightforward and which is preferable to other alternatives, including the use of confidence intervals. Probability forecasts relating to UK output growth and inflation, obtained using a small macroeconometric model, are presented. We discuss in detail the probability that inflation will fall within the Bank of England's target range and that recession will be avoided, both as separate single events and jointly. The probability forecasts are also used to provide insights on the interrelatedness of output growth and inflation outcomes at different horizons.Probability forecasting, long run structural VARs, macroeconometric modelling, probability forecasts of inflation, interest rates, output growth

A Pair-Wise Approach to Testing for Output and Growth Convergence

This paper proposes a pair-wise approach to testing for output convergence that considers all N(N-1)/2 possible pairs of log per capita output gaps across N economies. A general probabilistic definition of output convergence is also proposed, which suggests that all such output gap pairs must be stationary with a constant mean. The approach is compatible with individual output series having unit roots, does not involve the choice of a reference country in computation of output gaps, and can be applied when N is large relative to T (the time dimension of the panel). The proposed test is applied to output series in the Penn World Tables over 1950-2000, as well as to Maddion’s historical series over 1870-2000. Overall, the results do not support output convergence, and suggest that the findings of convergence clubs in the literature might be spurious. However, significant evidence of growth convergence is found, a result which is reasonably robust to the choice of the sample period and country groupings. Non-convergence of log per capita outputs combined with growth convergence suggests that while common technological progress seems to have been diffusing reasonably widely across economies, there are nevertheless important country-specific factors (for example, wars, famines, revolutions, regime and institutional changes) that render output gaps highly persistent, such that we can not be sure that the probability for the output gaps to lie within a fixed range will be non-zero.economic growth, panel data models, common technological shocks, convergence

Predictability of Asset Returns and the Efficient Market Hypothesis

This paper is concerned with empirical and theoretical basis of the Efficient Market Hypothesis (EMH). The paper begins with an overview of the statistical properties of asset returns at different frequencies (daily, weekly and monthly), and considers the evidence on return predictability, risk aversion and market efficiency. The paper then focuses on the theoretical foundation of the EMH, and show that market efficiency could co-exit with heterogeneous beliefs and individual irrationality so long as individual errors are cross sectionally weakly dependent in the sense defined by Chudik, Pesaran, and Tosetti (2010). But at times of market euphoria or gloom these individual errors are likely to become cross sectionally strongly dependent and the collective outcome could display significant departures from market efficiency. Market efficiency could be the norm, but it is likely to be punctuated with episodes of bubbles and crashes. The paper also considers if market inefficiencies (assuming that they exist) can be exploited for profit.market efficiency, predictability, heterogeneity of expectations, forecast averaging, equity, premium puzzle

Estimation and Inference in Large Heterogenous Panels with Cross Section Dependence

This paper presents a new approach to estimation and inference in panel data models with unobserved common factors possibly correlated with exogenously given individual-specific regressors and/or the observed common effects. The basic idea behind the proposed estimation procedure is to filter the individual-specific regressors by means of (weighted) cross-section aggregates such that asymptotically as the cross-section dimension (N) tends to infinity the differential effects of unobserved commond factors are eliminated. The estimation procedure has the advantage that it can be computed by OLS applied to an auxiliary regression where the observed regressors are augmented by cross sectional averages of the dependent variable and the individual specific regressors. It is shown that the proposed correlated common effects (CCE) estimators for the individual-specific regressors (and its pooled counterpart) are asymptotically unbiased as N approaches infinity, both when T (the time-series dimension) is fixed, and when N and T tend to infinity jointly. A generalization of these results to multi-factor structures is also provided. The estimation and inference in dynamic heterogenous panels with a residual factor structure will be addressed in a companion paper.cross section dependence, large panels, common correlated effects, heterogeneity, estimation and inference

Optimal Asset Allocation with Factor Models for Large Portfolios

An electronic version of the paper may be downloaded • from the SSRN website: www.SSRN.com • from the RePEc website: www.RePEc.org • from the CESifo website: Twww.CESifo-group.org/wp

Modelling Volatilities and Conditional Correlations in Futures Markets with a Multivariate t Distribution

This paper considers a multivariate t version of the Gaussian dynamic conditional correlation (DCC) model proposed by Engle (2002), and suggests the use of devolatized returns computed as returns standardized by realized volatilities rather than by GARCH type volatility estimates. The t-DCC estimation procedure is applied to a portfolio of daily returns on currency futures, government bonds and equity index futures. The results strongly reject the normal-DCC model in favour of a t-DCC specification. The t-DCC model also passes a number of VaR diagnostic tests over an evaluation sample. The estimation results suggest a general trend towards a lower level of return volatility, accompanied by a rising trend in conditional cross correlations in most markets; possibly reflecting the advent of euro in 1999 and increased interdependence of financial markets