相关与无关多样化对地区经济发展的影响研究——基于省际面板数据的实证检验

从经济增长和经济稳定两个维度研究了相关多样化、无关多样化与经济发展之间的关系。利用2003-2010年30个省级单位的面板数据,运用了多样化熵指标测度方法,将产业多样化分解为相关与无关两部分。研究表明：相关多样化、无关多样化与经济增长之间均存在非线性关系,与经济稳定只存在线性关系。结合现有的样本取值来看,相关多样化对经济增长有正向的促进作用,但不利于地区经济稳定;无关多样化有利于地区经济稳定,却不利于地区经济增长。     

General multivariate linear models for longitudional studies

Longitudinal studies occcur frequently in many different disciplines. To fully utilize the potential value of the information contained in a longitudinal data, various multivariate linear models have been proposed. The methodology and analysis are somewhat unique in their own ways and their relationships are not well understood and presented. This article describes a general multivaritate linear model for longitudinal data and attempts to provide a constructive formulation of the components in the mean response profile. The objective is to point out the extension and connections of some well-known models that have been obscured by different areas of application. More imporiantly, the model is expressed in a unified regression form from the subject matter considerations. Such an approach is simpler and more intuitive than other ways to modeling and parameter estimation. As a cmsequeace the analyses of the general class cf models for longitudional data can be casily implemented with standard software.     

Estimating and Testing Structural Changes in Multivariate Regressions

This paper considers issues related to estimation, inference, and computation with multiple structural changes that occur at unknown dates in a system of equations. Changes can occur in the regression coefficients and/or the covariance matrix of the errors. We also allow arbitrary restrictions on these parameters, which permits the analysis of partial structural change models, common breaks that occur in all equations, breaks that occur in a subset of equations, and so forth. The method of estimation is quasi‐maximum likelihood based on Normal errors. The limiting distributions are obtained under more general assumptions than previous studies. For testing, we propose likelihood ratio type statistics to test the null hypothesis of no structural change and to select the number of changes. Structural change tests with restrictions on the parameters can be constructed to achieve higher power when prior information is present. For computation, an algorithm for an efficient procedure is proposed to construct the estimates and test statistics. We also introduce a novel locally ordered breaks model, which allows the breaks in different equations to be related yet not occurring at the same dates.     

A joint test for parametric specification and independence in nonlinear regression models

This paper develops a testing procedure to simultaneously check (i) the independence between the error and the regressor(s), and (ii) the parametric specification in nonlinear regression models. This procedure generalizes the existing work of Sen and Sen [“Testing Independence and Goodness-of-fit in Linear Models,” Biometrika, 101, 927–942.] to a regression setting that allows any smooth parametric form of the regression function. We establish asymptotic theory for the test procedure under both conditional homoscedastic error and heteroscedastic error. The derived tests are easily implementable, asymptotically normal, and consistent against a large class of fixed alternatives. Besides, the local power performance is investigated. To calibrate the finite sample distribution of the test statistics, a smooth bootstrap procedure is proposed and found work well in simulation studies. Finally, two real data examples are analyzed to illustrate the practical merit of our proposed tests.     

Ceilings or floors? Gender wage gaps by education in Spain

This paper analyzes the gender gap throughout the wage distribution in Spain using data from the European Community Household Panel. Quantile regression and panel data techniques are used to estimate wage regressions. In contrast with the steep increasing pattern found in other countries, the flatter evolution of the Spanish gender gap hides an intriguing composition effect. For highly educated workers, in line with the conventional glass ceiling hypothesis, the gap increases as we move up the distribution. However, for less-educated workers the gap decreases. We label this novel fact as a floor pattern and argue that it can be explained by statistical discrimination exerted by employers in countries where less-educated women have low participation rates.

多元化战略与组织结构的匹配关系研究

要实现不同的多元化战略就应设计不同的内部组织结构 ,希望实现范围经济的相关多元化公司需着重于内部各业务单元之间的合作 ,而希望通过有效的内部管理来实现控制经济的非相关化多元化公司在组织结构设计上就应着重于各业务单元之间的竞争。一个多元化的企业如果希望有好的绩效就必须实现其多元化战略与组织结构和控制体系之间的匹配     

Packages for Estimating Finite Mixtures: A Review

We review five packages for estimating finite mixtures, BINOMIX, C.A. MAN, MIX, and the maximum likelihood routines of BMDP and STATA. The focus of the review is on numerical issues rather than matters such as user interface because the success or failure of an algorithm to yield a mixture model is likely to be the most important issue facing a researcher. The problem of suitable initial values is discussed throughout.     

Estimation of a rare sensitive attribute in probability proportional to size measures using Poisson distribution

We propose new variants of Land et al.’s [Estimation of a rare sensitive attribute using Poisson distribution. Statistics. 2011. DOI: 10.1080/02331888.2010.524300] randomized response model when a population consists of some clusters and the population is stratified with some clusters in each stratum. The estimator for the mean number of persons who possess a rare sensitive attribute, its variance, and the variance estimator are suggested when the parameter of a rare unrelated attribute is assumed to be known and unknown. The clusters are selected with and without replacement. When they are selected with replacement, the selecting probabilities for each cluster are defined depending on the cluster sizes and with equal probability. In addition, the variance comparison between a probability proportional to size (PPS) and PPS for stratification are performed. When the parameters vary in clusters, the stratified PPS has better efficiency than the PPS.