On Rao score and PearsonX 2 statistics in generalized linear models

The identity of the Rao score and PearsonX ² statistics is well known in the areas where the latter was first introduced: goodness-of-fit in contingency tables and binary responses. We show in this paper that the same identity holds when the two statistics are used for testing goodness-of-fit of Generalized Linear Models. We also highlight the connections that exist between the two statistics when they are used for the comparison of nested models. Finally, we discuss some merits of these unifying results. Work financially supported by cofin. MIUR grants 2000 and 2002.     

转型期实现内外均衡的政策搭配研究

中国在入世后的10年左右 ,正处于转型经济中。应该通过调节社会总需求、社会总供给等政策工具 ,实现合理搭配 ,以达到中国宏观经济的内外均衡     

基于EGARCH模型的我国股市信息对称性研究

利用过去17年我国上证综合指数的历史数据,根据股票市场大的波动周期分五阶段经过EGARCH(1,1)模型估计,以验证市场对信息冲出的反映情况.研究结果表明:中国股市存在很大的波动性,尚未达到弱有效性;存在正负杠杆效应交替出现的现象,表现出信息不对称性,但是这种不对称性在明显减小.     

Improved model selection criteria for SETAR time series models

The purpose of this paper is threefold. First, we obtain the asymptotic properties of the modified model selection criteria proposed by Hurvich et al. (1990. Improved estimators of Kullback-Leibler information for autoregressive model selection in small samples. Biometrika 77, 709–719) for autoregressive models. Second, we provide some highlights on the better performance of this modified criteria. Third, we extend the modification introduced by these authors to model selection criteria commonly used in the class of self-exciting threshold autoregressive (SETAR) time series models. We show the improvements of the modified criteria in their finite sample performance. In particular, for small and medium sample size the frequency of selecting the true model improves for the consistent criteria and the root mean square error (RMSE) of prediction improves for the efficient criteria. These results are illustrated via simulation with SETAR models in which we assume that the threshold and the parameters are unknown.     

Which Wald statistic? Choosing a parameterization of the Wald statistic to maximize power in k-sample generalized estimating equations

The Wald statistic is known to vary under reparameterization. This raises the question: which parameterization should be chosen, in order to optimize power of the Wald statistic? We specifically consider k-sample tests of generalized linear models (GLMs) and generalized estimating equations (GEEs) in which the alternative hypothesis contains only two parameters. An example is presented in which such an alternative hypothesis is of interest. Amongst a general class of parameterizations, we find the parameterization that maximizes power via analysis of the non-centrality parameter, and show how the effect on power of reparameterization depends on sampling design and the differences in variance across samples. There is no single parameterization with optimal power across all alternatives. The Wald statistic commonly used under the canonical parameterization is optimal in some instances but it performs very poorly in others. We demonstrate results by example and by simulation, and describe their implications for likelihood ratio statistics and score statistics. We conclude that due to poor power properties, the routine use of score statistics and Wald statistics under the canonical parameterization for GEEs is a questionable practice.     

转型期中国农村区域消费水平与结构的实证分析

农村消费市场低迷是制约我国经济发展的主要因素。运用主成分聚类方法及Panel Data数据模型,结合1994—2003年的时序截面数据,对我国农村区域消费水平与结构的差异进行静态与动态分析。     

基于用户技术接受模型的政府数据开放平台研究 ——以深圳政府数据开放平台为例

从用户使用视角出发,基于用户技术接受模型,以深圳市政府数据开放平台为例,设计14个观察指标,研究政府开放数据的有用性和易用性。深圳市政府数据开放平台具有开放有序、回应及时和激励正向三大特色,同时存在创设数据场景不丰富、获取数据资源途径单一、利用成果数量少及质量不高、平台用户评价不积极及参与度低等不足。据此,提出以用户需求为导向、提升用户数字素养、构建政府部门的激励约束机制和跨部门跨层级的协同机制等政策建议。     

投资者信心和中国宏观经济波动——基于MIDAS混频模型

将投资者信心指数引入MIDAS混频模型之中,可以考察新冠疫情背景下投资者信心对于中国宏观经济波动的影响。基于投资者信心指数和“三驾马车”对我国季度GDP增长率进行预测,通过实证发现:引入投资者信心指数的MIDAS混频模型在预测精准度方面和基准模型进行比较,预测精准度高于未加入投资者信心的模型,均方根残差比值更小;在多元MIDAS混频模型之中,加入投资者信心指数的回归模型对我国GDP的实时预报和短期预测结果更加稳定,可为决策者提供更加精确的参考区间;宏观经济的波动对投资者信心指数变化反应,和投资、消费和进出口相比是最灵敏的。这为定量追踪宏观经济波动提供了一个新的视角。     

品牌延伸:资产价值转移与理论模型创建

本文通过对品牌延伸(Brand Extension)的研究综述和实证研究,提出决定品牌延伸的三大因子,并在此基础上构成品牌资产价值(Brand Asset Value),进而研究其在品牌延伸过程中的价值转移,从而构成了评估品牌延伸成败的标准,最终将各种因子和评估标准进行整合,提出了品牌延伸的理论模型。     

冲突视角下运输订单商业竞争战略研究

运用图模型理论研究冲突视角下中欧班列运营过程中运输订单商业竞争战略,构建“渝新欧”班列运营商、“苏满欧”班列运营商和昆山IT企业之间的商业竞争冲突模型。利用TOPSIS法评估班列的运输效率,确定决策者偏好,通过计算均衡解获得符合各决策者利益的理性对策。借助灵敏度分析研究决策者偏好改变对模型冲突结果的影响。研究表明:在竞争中,运输效率较低的一方可以通过降低价格弥补自身劣势而获得订单;运输效率较高的一方只有通过降价才能获得订单。该研究为班列运营商提供利益冲突中的商业竞争战略,能为顾客企业选择高效合理的运输线路提供有效的战略决策,同时亦能为宏观调控者规范市场、提高市场运输效率提供有效的政策启示。