Efficient semiparametric estimation for endogenously stratified regression via smoothed likelihood

This paper presents efficient semiparametric estimators for endogenously stratified regression with two strata, in the case where the error distribution is unknown and the regressors are independent of the error term. The method is based on the use of a kernel-smoothed likelihood function which provides an explicit solution for the maximization problem for the unknown density function without losing information in the asymptotic limit. We consider both standard stratified sampling and variable probability sampling, and allow for the population shares of the strata to be either unknown or known a priori.     

Dynamics of international integration of government securities’ markets

This paper investigates the dynamics of international government bond market integration in six of the G7 economies over two decades leading up to the global crisis. It examines whether such integration had been significant; the extent to which integration at the short and long end of the yield curve differed; the nature of such integration; and the extent of the decoupling of the long rates from short rates. These issues are investigated using the rigorous smooth-transition copula-GARCH model framework. The results show that integration at the long end of the yield curve had been increasing, had become pronounced, and was significantly greater than at the short end. Decoupling between the short and long end of the yield curve was notable, with important implications for the efficacy of monetary policy in the period before the crisis.     

BE/ME and E/P work better than ME/BE or P/E in regressions

Researchers often form ratios of variables to measure firm characteristics, but which ratios create the most powerful tests? For example, if we use ratios of book value of equity (BE) and market value of equity (ME), or earnings (E) and price (P), does it matter which variable appears in the denominator? Any variable in the denominator, when close to zero, creates outliers and is less likely to produce effective tests. Our tests, using data from 1972 to 2008, indicate the choice between reciprocals often produces significantly different outcomes. While ME/BE is a more commonly used control variable than BE/ME or LN(BE/ME), we find the latter two produce better results, even if the data are trimmed to mitigate the outlier problem. Similarly, using E/P generally produces better results than P/E, and while ratios with book value of assets (BA) in the numerator work better than those with it in the denominator, the difference is less pronounced than when BE or E is part of the ratio. While the focus of our empirical findings is on growth measures, the principal applies anytime a ratio has a denominator that is frequently near zero.     

论B2C在适应性方面存在的问题

随着互联网和计算机的不断发展,电子商务已越来越受到大众的普遍关注。B2C在我国得到迅速的发展,但是在适应性方面存在的问题成为阻碍其发展的障碍。     

An alternative bivariate zero-inflated negative binomial regression model using a copula

We propose an alternative bivariate zero-inflated negative binomial (BZINB) regression model based on a copula. The empirical result shows that the proposed model performs better than the existing BZINB models in terms of the maximum log-likelihood and the AIC.     

浅析我国B2C市场竞争策略

据易观国际发布的数据显示,2008年中国B2C市场销售规模达81亿.B2C平台已经日益成为一条重要的销售渠道,与传统的渠道相比具有价格低,购物方便等优势.研究如何使用B2C平台,打造立体化销售渠道,对提升企业生存能力和盈利能力具有重要的现实意义.本文首先分析了中国B2C市场的现状和发展趋势,然后提出我国B2C市场竞争策略.     

Farsighted network formation

This paper studies a model of dynamic network formation when individuals are farsighted: players evaluate the desirability of a “current” move in terms of its consequences on the entire discounted stream of payoffs. We define a concept of equilibrium which takes into account farsighted behavior of agents and allows for limited cooperation amongst agents. We show that an equilibrium process of network formation exists. We also show that there are valuation structures in which no equilibrium strategy profile can sustain efficient networks. We then provide sufficient conditions under which the equilibrium process will yield efficient outcomes.