Identifying Treatment Effects Under Data Combination

We consider the identification of counterfactual distributions and treatment effects when the outcome variables and conditioning covariates are observed in separate data sets. Under the standard selection on observables assumption, the counterfactual distributions and treatment effect parameters are no longer point identified. However, applying the classical monotone rearrangement inequality, we derive sharp bounds on the counterfactual distributions and policy parameters of interest.     

基于模态分解的Hilbert-Huang变换

Hilbert-Huang变换(HHT)是近年来发展起来的一种新的时频分析方法。本文首先阐述了基于经验模态分解(EMD)的Hilbert—Huang变换(HHT)的基本原理及英特点,然后将该方法用于实例,对比分析了HHT变换和传统的傅立叶变换的实验结杲,进而说明了该方法用于信号时频分析的可行性和优越性。     

SEPARATION, WEAK EXOGENEITY, AND P-T DECOMPOSITION IN COINTEGRATED VAR SYSTEMS WITH COMMON FEATURES

The aim of this paper is to study the concept of separability in multiple nonstationary time series displaying both common stochastic trends and common stochastic cycles. When modeling the dynamics of multiple time series for a panel of several entities such as countries, sectors, firms, imposing some form of separability and commonalities is often required to restrict the dimension of the parameter space. For this purpose we introduce the concept of common feature separation and investigate the relationships between separation in cointegration and separation in serial correlation common features. Loosely speaking we investigate whether a set of time series can be partitioned into subsets such that there are serial correlation common features within the sub-groups only. The paper investigates three issues. First, it provides conditions for separating joint cointegrating vectors into marginal cointegrating vectors as well as separating joint short-term dynamics into marginal short-term dynamics. Second, conditions for making permanent-transitory decompositions based on marginal systems are given. Third, issues of weak exogeneity are considered. Likelihood ratio type tests for the different hypotheses under study are proposed. An empirical analysis of the link between economic fluctuations in the United States and Canada shows the practical relevance of the approach proposed in this paper.     

中国代际收入传递趋势及教育在传递中的作用

本文利用中国健康营养调查（CHNS）数据,实证检验了出生于1949-1990年男性是否存在代际收入传递,并分析了其变化趋势和教育在代际收入传递中的作用机制。估计结果表明,1949- 1990年代际收入传递程度总体上不断加强,其中60年代初期和80年代初期出现两次传递高峰。中等收入水平者受父辈的影响及加强趋势均最高,呈现双倒“U”特征。城镇传递加强趋势约是农村2倍,城镇高收入水平者受父辈的影响更强,农村则低收入水平者所受影响更强。对教育作用机制分解发现,教育对代际收入传递的解释程度在农村达到26%,城镇则达到36%。家庭环境导致的子女教育机会不平等是影响代际收入传递趋势变化的最主要原因。随着国民教育水平提高,在中国教育的作用也出现了”组合效应”特征。     

Treatment Effects: A Bayesian Perspective

This paper contributes to the emerging Bayesian literature on treatment effects. It derives treatment parameters in the framework of a potential outcomes model with a treatment choice equation, where the correlation between the unobservable components of the model is driven by a low-dimensional vector of latent factors. The analyst is assumed to have access to a set of measurements generated by the latent factors. This approach has attractive features from both theoretical and practical points of view. Not only does it address the fundamental identification problem arising from the inability to observe the same person in both the treated and untreated states, but it also turns out to be straightforward to implement. Formulae are provided to compute mean treatment effects as well as their distributional versions. A Monte Carlo simulation study is carried out to illustrate how the methodology can easily be applied.     

SVARMA模型的设定、方差分解分析和应用

本文首先研究了传统凯恩斯主义IS-LM-PC模型的SVARMA模型表示,为宏观经济计量分析建立SVARMA模型提供了模型设定依据;其次,建立了VARMA/SVARMA模型方差分解分析方法;另外,基于SVARMA模型对中国宏观经济政策的动态效应进行了实证分析,实证分析发现（1）SVARMA模型与SVAR模型的分析结果存在重要的区别;（2）在政策实施6-7期前后,财政政策和货币政策对抑制通货膨胀的效果发生逆转;（3）宏观经济的价格水平存在粘性;（4）货币供给冲击对通货膨胀率的变化具有滞后的正向影响,对实际产出的影响不明显等。     

中国城乡多维贫困的测度及比较

传统的仅用收入或消费来衡量贫困的方法只能提供单一的信息,从多维角度则能够较全面地认识贫困。本文利用CHNS数据库中2000年和2009年数据,借鉴了多维贫困指数的构造及分解方法,对近十年来中国城乡多维贫困进行了测度、分解及分析,认为总体上城乡贫困程度均有所减轻,农村贫困严重于城市,应重视医疗健康保险、卫生设施、城市住房、做饭燃料等维度上的贫困,同时降低中西部省份的贫困。     

增值税“扩围”对我国城镇居民收入的分配效应

本文提出了一个新的增值税收入分配效应的分解方法,并运用2007-2011年我国城镇分组家庭的消费支出数据,分析了增值税“扩围”对居民收入分配的影响。实证结论表明,增值税“扩围”后不同收入等级的增值税税负随着收入的增加而降低,增值税对食品、居住、家庭设备用品及服务等领域具有不均等效应,而对衣着、医疗保健、交通和通信、教育文化与娱乐服务等领域具有均等效应。我国增值税总体上呈现不均等效应,但不均等效应逐步减弱,其中平均税率和消费支出差异的分配效应是决定因素。     

货币供应量对股市影响的实证分析

笔者利用我国货币供应量和股票价格指数的相关数据,通过构建VAR模型,分别对牛市和熊市两种行情下货币供应量对股票价格指数的影响进行实证分析。研究表明:两种行情下,货币供应量与股票价格指数均存在长期均衡关系,在牛市行情下,货币供应量对股票价格指数的上涨具有积极的促进作用,而在熊市行情下,货币供应量对股票价格指数影响不大。     

协同运输的路线整合问题研究

本文研究协同运输的路线整合问题(CTRIP):允许所有的O-D流(运输任务)在规定的路线长度内任意采取直通运输、单点中转、两点中转的整合运输路线,整合运输的中枢路段在支付固定成本后可产生运费折扣,如何选择O-D流的整合路线使得总成本最小? CTRIP广泛应用于航空、物流、快递等领域的整合运输实践。论文构造了CTRIP的混合整数规划模型和Benders分解算法,实验显示,算法表现出非常好的计算绩效。最后,我们利用一个具体实例对CTRIP与已有研究展开了比较,结论显示CTRIP更能保证中枢路段的规模优势 。