Asymptotic distribution of the cointegrating vector estimator in error correction models with conditional heteroskedasticity

This paper explores the asymptotic distribution of the cointegrating vector estimator in error correction models with conditionally heteroskedastic errors. Asymptotic properties of the maximum likelihood estimator (MLE) of the cointegrating vector, which estimates the cointegrating vector and the multivariate GARCH process jointly, are provided. The MLE of the cointegrating vector follows mixture normal, and its asymptotic distribution depends on the conditional heteroskedasticity and the kurtosis of standardized innovations. The reduced rank regression (RRR) estimator and the regression-based cointegrating vector estimators do not consider conditional heteroskedasticity, and thus the efficiency gain of the MLE emerges as the magnitude of conditional heteroskedasticity increases. The simulation results indicate that the relative power of the t-statistics based on the MLE improves significantly as the GARCH effect increases.     

Market Consolidation and Productivity Growth in U.S. Wireline Telecommunications: Stochastic Frontier Analysis vs. Malmquist Index

This study analyzes the merger effects for 25 Incumbent Local Exchange Carriers over the period 1996–2005 using stochastic frontier analysis with a time-varying inefficiency model. We further conduct a comparison of results between the stochastic frontier analysis and the Malmquist index method. The empirical results indicate that the sample of telecommunications firms has experienced deterioration in average productivity growth following mergers. Significantly, both approaches suggest that firms that do not merge underperform in terms of average productivity growth.     

Pythagorean generalization of testing the equality of two symmetric positive definite matrices

We provide a new test for equality of two symmetric positive-definite matrices that leads to a convenient mechanism for testing specification using the information matrix equality or the sandwich asymptotic covariance matrix of the GMM estimator. The test relies on a new characterization of equality between two $k$ dimensional symmetric positive-definite matrices $A$ and $B$: the traces of $A{B}^{?1}$ and $B{A}^{?1}$ are equal to $k$ if and only if $A=B$. Using this simple criterion, we introduce a class of omnibus test statistics for equality and examine their null and local alternative approximations under some mild regularity conditions. A preferred test in the class with good omni-directional power is recommended for practical work. Monte Carlo experiments are conducted to explore performance characteristics under the null and local as well as fixed alternatives. The test is applicable in many settings, including GMM estimation, SVAR models and high dimensional variance matrix settings.     

Tests for zero inflation in a bivariate zero‐inflated Poisson model

The score test statistics for testing zero inflation and covariance parameter are proposed in the bivariate zero‐inflated Poisson (BZIP) regression model. The Monte Carlo studies show that the score test and likelihood ratio test for testing zero inflation underestimate the nominal significance level, while the score test for covariance parameter keeps the significance level close to the nominal one. To overcome this nominal level underestimation, we propose a bootstrap method of the score test for the testing problem of zero inflation. An empirical example with covariates is provided to illustrate the results. In addition, score test for zero inflation is also proposed in the BZIP model, which allows a flexible dependence structure using copula.     

Determinants of Anti‐Trafficking Policies: Evidence from a New Index

We develop an index measuring the three main dimensions – prosecution, protection, and prevention – of the anti‐trafficking policies of the governments of up to 180 countries over the 2000?2010 period. Overall, developed countries perform better than the rest of the world; compliance with prosecution policy is highest, while governmental efforts to protect victims of human trafficking remain weakest. We employ the new indices to investigate which factors determine anti‐trafficking policies. We find that compliance with anti‐trafficking policies significantly decreases with corruption and is higher in countries that also respect the rights of women. We also find some tentative evidence for spatial dependence in anti‐trafficking policies.     

Earnings Management Surrounding CEO Turnover: Evidence from Korea

This article examines the empirical relation between chief executive officer (CEO) turnover and earnings management in Korea using a sample of 403 CEO turnovers and 806 non‐turnover control firms during the period 2001–2010. We classify CEO turnovers into four types depending on whether the departure of the outgoing CEO is peaceful or forced and whether the incoming CEO is promoted from within or recruited from outside the firm. We measure earnings management by both discretionary accruals and real activities management. We also control for the endogeneity of CEO turnover and a potential selection bias using 2SLS and Heckman's two‐stage approach. After controlling for corporate financial performance and governance structure, we find upward earnings management by the departing CEO only when the departure is forced and the new CEO is an insider. In this case, the new CEO also engages in downward earnings management using both discretionary accruals and real activities management. We also find some evidence that the new CEO recruited from outside the firm manages discretionary accruals upward following the peaceful departure of his predecessor. In all other types of CEO turnover, we do not find evidence of significant earnings management by either CEO.     

Nonlinear mean reversion in the term structure of interest rates

The expectations hypothesis implies that the yield curve provides information on the future change in the short-term interest rate. However, transaction costs exist in the financial market, which prevent investors from realizing the arbitrage opportunity, when the arbitrage does not fully cover the transaction costs. The purpose of this paper is to assess the effect of transaction costs on the predictability of the term structure by using the threshold vector error correction model, which allows for the nonlinear adjustment to the long-run equilibrium relationship. A significant amount of threshold effect is found, and the adjustment coefficients are regime-dependent. The empirical result supports the nonlinear mean reversion in the term structure of interest rates.     

Testing for non-nested conditional moment restrictions using unconditional empirical likelihood

We propose non-nested hypothesis tests for conditional moment restriction models based on the method of generalized empirical likelihood (GEL). By utilizing the implied GEL probabilities from a sequence of unconditional moment restrictions that contains equivalent information of the conditional moment restrictions, we construct Kolmogorov–Smirnov and Cramér–von Mises type moment encompassing tests. Advantages of our tests over Otsu and Whang’s (2011) tests are: (i) they are free from smoothing parameters, (ii) they can be applied to weakly dependent data, and (iii) they allow non-smooth moment functions. We derive the null distributions, validity of a bootstrap procedure, and local and global power properties of our tests. The simulation results show that our tests have reasonable size and power performance in finite samples.     

A Ricardian Analysis of the Distribution of Climate Change Impacts on Agriculture across Agro-Ecological Zones in Africa

This paper examines the distribution of climate change impacts across the sixteen Agro-Ecological Zones (AEZs) of Africa. We combine net revenue from livestock and crops and regress total net revenue on a set of climate, soil, and socio-economic variables with and without country fixed effects. Although African crop net revenue is very sensitive to climate change, combined livestock and crop net revenue is more climate resilient. With the hot and dry CCC climate scenario, average damage estimates reach 27% by 2100, but with the mild and wet PCM scenario, African farmers will benefit. The analysis of AEZs implies that the effects of climate change will be quite different across Africa. For example, currently productive areas such as dry/moist savannah are more vulnerable to climate change while currently less productive agricultural zones such as humid forest or sub-humid AEZs become more productive in the future. S. Niggol Seo is the Consultant to the World Bank.