Estimation of the number of jumps of the jump regression functions

This paper suggests an estimator of the number of jumps of the jump regression functions. The estimator is based on the difference between right and left onesided kernel smoothers. It is proved to be a.s. consistent. Some results about its rate of convergence are also provided.     

经济增速放缓与经济波动对居民福利影响的阶段差异分析

 本文基于中国1952-2007年时序数据定量研究经济增速放缓的福利损失和经济波动的福利损失,并侧重考察两种福利损失的大小关系在改革开放和经济体制改革目标确立前后的阶段差异。研究发现,无论是总体而言,还是在中国经济发展的不同阶段,经济波动的福利损失并不必然远小于经济增速放缓的福利损失,在相关参数的合理取值范围内,经济波动的福利损失大于经济增速放缓的福利损失是相当普遍的情形。因此,中国政府部门在重视长期经济增长的同时,不能草率否定短期经济稳定的重要性。     

Tuning Parameter Estimation in Penalized Least Squares Methodology

The efficiency of the penalized methods (Fan and Li, 2001 Fan , J. , Li , R. ( 2001 ). Variable selection via nonconcave penalized likelihood and its oracle properties . Journal of the American Statistical Association 96 : 1348 – 1360 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) depends strongly on a tuning parameter due to the fact that it controls the extent of penalization. Therefore, it is important to select it appropriately. In general, tuning parameters are chosen by data-driven approaches, such as the commonly used generalized cross validation. In this article, we propose an alternative method for the derivation of the tuning parameter selector in penalized least squares framework, which can lead to an ameliorated estimate. Simulation studies are presented to support theoretical findings and a comparison of the Type I and Type II error rates, considering the L ₁, the hard thresholding and the Smoothly Clipped Absolute Deviation penalty functions, is performed. The results are given in tables and discussion follows.     

Analyzing Supersaturated Designs by Means of an Information Based Criterion

The cost and time consumption of many industrial experimentations can be reduced using the class of supersaturated designs since this can be used for screening out the important factors from a large set of potentially active variables. A supersaturated design is a design for which there are fewer runs than effects to be estimated. Although there exists a wide study of construction methods for supersaturated designs, their analysis methods are yet in an early research stage. In this article, we propose a method for analyzing data using a correlation-based measure, named as symmetrical uncertainty. This method combines measures from the information theory field and is used as the main idea of variable selection algorithms developed in data mining. In this work, the symmetrical uncertainty is used from another viewpoint in order to determine more directly the important factors. The specific method enables us to use supersaturated designs for analyzing data of generalized linear models for a Bernoulli response. We evaluate our method by using some of the existing supersaturated designs, obtained according to methods proposed by Tang and Wu (1997 Tang , B. , Wu , C. F. J. (1997). A method for constructing supersaturated designs and its E(s ²)-optimality. Canadian Journal of Statistics 25:191–201.[Crossref], [Web of Science ®] , [Google Scholar]) as well as by Koukouvinos et al. (2008 Koukouvinos , C. , Mylona , K. , Simos , D. E. ( 2008 ). E(s ²)-optimal and minimax-optimal cyclic supersaturated designs via multi-objective simulated annealing . Journal of Statistical Planning and Inference 138 : 1639 – 1646 .[Crossref], [Web of Science ®] , [Google Scholar]). The comparison is performed by some simulating experiments and the Type I and Type II error rates are calculated. Additionally, Receiver Operating Characteristics (ROC) curves methodology is applied as an additional statistical tool for performance evaluation.     

收入、预期寿命和社会养老保险收入再分配效应

本文在考虑职工基本养老保险典型不同缴费基数参保者寿命存在异质性的情况下，通过内部收益率的计算考察典型不同缴费基数参保者之间的养老金收入再分配效应。首先根据省级宏观截面数据估计了职工基本养老保险典型不同缴费基数参保者退休时的平均余命，再据此分别计算和比较不同参保群体的内部收益率。 研究发现职工基本养老保险制度总体上呈现微弱的正向收入再分配效应。虽然低缴费基数参保者内部收益率略高于中、高缴费基数参保职工，但其内部收益率因相对较短的寿命而大大降低。这也提醒政策制定者在研究制定延迟退休、社会养老保险全国统筹等政策时需要充分考虑参保职工内部不同群体间的平均预期寿命差别，对低收入参保者予以特别关注。     

税收激励与企业劳动雇佣——来自薪酬抵税政策的“准自然实验”

在经济下行压力不断加大的形势下,如何“稳就业”成为了各界关注的热点问题。本文以2008 年推行的薪酬抵税政策作为“准自然实验”捕捉企业税负的外生变化,并以2000-2018 年A 股上市公司数据作为研究样本,利用双重差分法考察了税收激励与企业雇佣行为之间的因果关系。实证结果表明:薪酬抵税政策带来了额外的税收优惠,进而促进了企业的雇佣需求,在有效排除共同趋势、预期效应、政策叠加效应以及反向因果问题后,这一结论依然稳健;异质性检验中发现,薪酬抵税政策对企业雇佣的激励效应在民营企业,成本转嫁能力较弱、劳动密集度较高以及处于市场化程度较高区域的企业中表现更加明显,这意味着企业对劳动力成本的变化越敏感,这一政策的作用效果就越好;薪酬抵税政策显著地提升了企业的经营绩效。本文的研究有助于深入理解税收影响企业行为的微观机理,对于政府利用税收政策扩大就业具有重要启示。     

中美两国妇女生育双胞胎率的比较分析

本文比较了中美两国育龄妇女生育双胞胎率的差异以及与年龄的关系,指出一卵双胎率和二卵双胎率大小．不但与妇女妊娠年龄有关,而且与遗传有关．     

Wavelet‐Based Testing for Serial Correlation of Unknown Form in Panel Models

Wavelet analysis is a new mathematical method developed as a unified field of science over the last decade or so. As a spatially adaptive analytic tool, wavelets are useful for capturing serial correlation where the spectrum has peaks or kinks, as can arise from persistent dependence, seasonality, and other kinds of periodicity. This paper proposes a new class of generally applicable wavelet‐based tests for serial correlation of unknown form in the estimated residuals of a panel regression model, where error components can be one‐way or two‐way, individual and time effects can be fixed or random, and regressors may contain lagged dependent variables or deterministic/stochastic trending variables. Our tests are applicable to unbalanced heterogenous panel data. They have a convenient null limit N(0,1) distribution. No formulation of an alternative model is required, and our tests are consistent against serial correlation of unknown form even in the presence of substantial inhomogeneity in serial correlation across individuals. This is in contrast to existing serial correlation tests for panel models, which ignore inhomogeneity in serial correlation across individuals by assuming a common alternative, and thus have no power against the alternatives where the average of serial correlations among individuals is close to zero. We propose and justify a data‐driven method to choose the smoothing parameter—the finest scale in wavelet spectral estimation, making the tests completely operational in practice. The data‐driven finest scale automatically converges to zero under the null hypothesis of no serial correlation and diverges to infinity as the sample size increases under the alternative, ensuring the consistency of our tests. Simulation shows that our tests perform well in small and finite samples relative to some existing tests.