Multivariate Stochastic Volatility Models with Correlated Errors

We develop a Bayesian approach for parsimoniously estimating the correlation structure of the errors in a multivariate stochastic volatility model. Since the number of parameters in the joint correlation matrix of the return and volatility errors is potentially very large, we impose a prior that allows the off-diagonal elements of the inverse of the correlation matrix to be identically zero. The model is estimated using a Markov chain simulation method that samples from the posterior distribution of the volatilities and parameters. We illustrate the approach using both simulated and real examples. In the real examples, the method is applied to equities at three levels of aggregation: returns for firms within the same industry, returns for different industries, and returns aggregated at the index level. We find pronounced correlation effects only at the highest level of aggregation.     

Three Lenses on Occupations and Professions in Organizations: Becoming,Doing, and Relating

Management and organizational scholarship is overdue for a reappraisal of occupations and professions as well as a critical review of past and current work on the topic. Indeed, the field has largely failed to keep pace with the rising salience of occupational and professional (as opposed to organizational) dynamics in work life. Moreover, not only is there a dearth of studies that explicitly take occupational or professional categories into account, but there is also an absence of a shared analytical framework for understanding what occupations and professions entail. Our goal is therefore two-fold: first, to offer guidance to scholars less familiar with this terrain who encounter occupational or professional dynamics in their own inquiries and, second, to introduce a three-part framework for conceptualizing occupations and professions to help guide future inquiries. We suggest that occupations and professions can be understood through lenses of “becoming”, “doing”, and “relating”. We develop this framework as we review past literature and discuss the implications of each approach for future research and, more broadly, for the field of management and organizational theory.     

Women on boards and bank efficiency in ASEAN-5: the moderating role of the independent directors

Corporate governance codes around the world promote women’s presence in corporate board. The extant literature suggests women directors contribute to improve monitoring and advisory role of the board. This study aims to examine the role of independent women directors in improving banks’ efficiency. Using 102 commercial banks from ASEAN-5 countries for a period of 1999–2012, we run generalized method of moments models to test the relationship between the variables. Our results show that banks with independent women directors on board contribute significantly to the bank’s efficiency level. Contrary to the literature, we found that the appointment of women directors or independent directors alone does not significantly enhance banks’ efficiency. The result suggests that women directors are more effective on boards if they are also appointed as independent directors. This finding implies that a combination of corporate governance mechanism is more powerful than relying on a single element of corporate governance.     

Psychological antecedents and motivational models of collective action: examining the role of perceived effectiveness in political protest participation

The present study examines Hong Kong citizens’ willingness to participate in the Occupy Central/Umbrella Movement. A representative adult survey (N = 816) was conducted before the Occupy Central protest in 2014. Regression analyses showed that the core psychological antecedents of political identity (psychological attachment to pro-democracy parties and Occupy activists), political efficacy (perceived effectiveness of individual and movement agency), ideology (dissatisfaction with the pace of democratization), and emotion (anger with the political environment) were significant predictors of likely participation. Measures of perceived effectiveness of the Occupy movement to achieve successful outcomes (i.e. its ability to influence public opinion, strengthen the pro-democracy cause in Hong Kong, and facilitate opinion expression) explained additional variance even after controlling for demographics and the core antecedents. An integrated motivational model of collective action was then tested using structural equation modeling. Findings are consistent with the extant literature. Moral convictions (democracy as a fundamental human value) served as an antecedent of identity, efficacy, ideology, and anger, while identity exhibited direct and indirect effects on participation through efficacy, ideology and anger. The model also pointed to a role for perceived effectiveness, supporting the idea that individuals are motivated by other potential outcomes of a protest beyond achieving its primary objective.     

Transforming Access to Research Literature for Developing Countries

Abstract

The economic development of a country depends heavily on its scientific strength and ability to resolve problems in such areas as public health, infectious disease, environmental management, or industrial progress. Access to research information traditionally depends on ability to pay, which has a negative impact on developing countries. A number of new initiatives address this imbalance, ranging from consortial licensing and new publishing models to the Open Access Initiative, and have the ability to meet the needs of research in financially constrained countries. The advent of the Open Access strategies, particularly interoperable institutional archives, has the potential to revolutionize access to essential research.     

Nonparametric inference for the joint distribution of recurrent marked variables and recurrent survival time

Time between recurrent medical events may be correlated with the cost incurred at each event. As a result, it may be of interest to describe the relationship between recurrent events and recurrent medical costs by estimating a joint distribution. In this paper, we propose a nonparametric estimator for the joint distribution of recurrent events and recurrent medical costs in right-censored data. We also derive the asymptotic variance of our estimator, a test for equality of recurrent marker distributions, and present simulation studies to demonstrate the performance of our point and variance estimators. Our estimator is shown to perform well for a wide range of levels of correlation, demonstrating that our estimators can be employed in a variety of situations when the correlation structure may be unknown in advance. We apply our methods to hospitalization events and their corresponding costs in the second Multicenter Automatic Defibrillator Implantation Trial (MADIT-II), which was a randomized clinical trial studying the effect of implantable cardioverter-defibrillators in preventing ventricular arrhythmia.     

Efficient Markov chain Monte Carlo with incomplete multinomial data

We propose a block Gibbs sampling scheme for incomplete multinomial data. We show that the new approach facilitates maximal blocking, thereby reducing serial dependency and speeding up the convergence of the Gibbs sampler. We compare the efficiency of the new method with the standard, non-block Gibbs sampler via a number of numerical examples.     

Does the marriage market sex ratio affect parental sex selection? Evidence from the Chinese census

Recent increases in the (male/female) sex ratio at birth in eastern Asia are thought to be associated with a preference for sons and to result from parental sex selection. However, males are less likely to marry and to have offspring as the ratio increases, and that decreases the expected number of grandchildren. Using data from the 2000 Chinese census, we test whether the sex ratio in the marriage market has an effect on the gender of subsequent births and hence on the sex ratio of the birth cohort. The slow population growth caused by the Great Famine in the early 1960s and the quick recovery that followed produced major changes in the sex ratio for those of marriageable age two decades later. We estimate that an increase of 1 % in the number of marriageable males relative to females, the marriage market sex ratio, would decrease the probability of having a son by 0.02 percentage points. That implies that the Great Famine, which occurred around 1960, led to an increase in the early 1980s of 5.8 extra male births per 100 females.     

Strassen type limit points for moving averages of a wiener process

Let {W(s); 8 ≥ 0} be a standard Wiener process, and let β_N = (2a_N (log (N/a_N) + log log N)^-1/2, 0 < α_N ≤ N < ∞, where α_N↑ and α_N/N is a non-increasing function of N, and define γ_N(t) = β_N[W(n_N + ta_N) ? W(n_N)), 0 ≥ t ≥ 1, with n_N = N – a_N. Let K = {x ? C[0,1]: x is absolutely continuous, x(0) = 0 and }. We prove that, with probability one, the sequence of functions {γ_N(t), t ? [0,1]} is relatively compact in C[0,1] with respect to the sup norm ||·||, and its set of limit points is K. With a_N = N, our result reduces to Strassen's well-known theorem. Our method of proof follows Strassen's original, direct approach. The latter, however, contains an oversight which, in turn, renders his proof invalid. Strassen's theorem is true, of course, and his proof can also be rectified. We do this in a somewhat more general context than that of his original theorem. Applications to partial sums of independent identically distributed random variables are also considered.