Lag Length Selection for Unit Root Tests in the Presence of Nonstationary Volatility

A number of recent papers have focused on the problem of testing for a unit root in the case where the driving shocks may be unconditionally heteroskedastic. These papers have, however, taken the lag length in the unit root test regression to be a deterministic function of the sample size, rather than data-determined, the latter being standard empirical practice. We investigate the finite sample impact of unconditional heteroskedasticity on conventional data-dependent lag selection methods in augmented Dickey–Fuller type regressions and propose new lag selection criteria which allow for unconditional heteroskedasticity. Standard lag selection methods are shown to have a tendency to over-fit the lag order under heteroskedasticity, resulting in significant power losses in the (wild bootstrap implementation of the) augmented Dickey–Fuller tests under the alternative. The proposed new lag selection criteria are shown to avoid this problem yet deliver unit root tests with almost identical finite sample properties as the corresponding tests based on conventional lag selection when the shocks are homoskedastic.     

Rethinking the Univariate Approach to Panel Unit Root Testing: Using Covariates to Resolve the Incidental Trend Problem

In an influential article, Hansen showed that covariate augmentation can lead to substantial power gains when compared to univariate tests. In this article, we ask if this result extends also to the panel data context? The answer turns out to be yes, which is maybe not that surprising. What is surprising, however, is the extent of the power gain, which is shown to more than outweigh the well-known power loss in the presence of incidental trends. That is, the covariates have an order effect on the neighborhood around unity for which local asymptotic power is negligible.     

Multilevel modelling of refusal and non-contact in household surveys: evidence from six UK Government surveys

Summary.  We analyse household unit non-response in six major UK Government surveys by using a multilevel multinomial modelling approach. The models are guided by current conceptual frameworks and theories of survey participation. One key feature of the analysis is the investigation of the extent to which effects of household characteristics are survey specific. The analysis is based on the 2001 UK Census Link Study, which is a unique source of data containing an unusually rich set of auxiliary variables. The study contains the response outcome of six surveys, linked to census data and interviewer observations for both respondents and non-respondents.     

试论珠江三角洲的围董及围董会

围董及围董会是珠江三角洲人民在清末与民国时期,自发组成的一种民间性基层水利管理机构。它在动员群众修筑堤围、筹集资金、防汛抢险、调解水利纠纷等方面,始终扮演了较为重要的角色。自清末至民国,政府对围董(会)的管理与渗透虽日益加强,但其权威却始终未能深入到水利基层管理中去。     

基于FESA/TRIZ的机械产品创新设计方法

机械产品的设计一直注重于市场需求和产品功能的开发,随着科学和技术的发展,环境因素变得越来越重要。 提出一种基于功能一环境一结构分析( FESA)与TRIZ的机械产品创新设计方法,通过分析机械产品结构之间的功能要素 以及功能要素与环境要素的相互作用关系,确定机械产品中存在的问题。建立根原因模型图,寻找结构设计上的不足和 缺陷,利用TRIZ创新理论来实现机械产品的改进创新。通过污水处理系统的创新设计实例验证了该方法的可行性。     

浅论单位盗窃的立法完善

单位盗窃行为的性质众说不一 ,本文从犯罪的本质、盗窃罪的主要特征、司法实践的刑事处理论证 ,认为单位盗窃属于犯罪行为 ,并提出增设单位盗窃罪的设想。     

以民为本:中国共产党从革命到执政的实践基础

中国共产党的三代领导集体 ,经历了革命、执政、改革开放和社会主义市场经济的社会实践 ,在不同历史时期 ,牢记为人民服务的宗旨 ,赢得了人民的支持 ,也向人民交出了无愧于时代的出色答卷。新的世纪 ,我党仍面临严峻考验。但中外历史经验证明 ,只要以民为本 ,服务人民 ,就能使社会主义祖国走向繁荣、富强     

我国历代粮食亩产量的变化及其原因分析

粮食亩产量的高低是以精耕细作为基础 ,走集约化经营道路的我国农业生产中的关键问题。历代统治者都非常关心如何提高粮食单产 ,以便解决泱泱大国人多地少的矛盾。粮食亩产量受许多自然因素和社会因素、有利因素和不利因素的影响 ,通过考察历史时期的粮食亩产量变化 ,分析其动因 ,找到提高粮食单产和总产的有效途径 ,指出了我国农业生产应该依靠科技力量 ,保护生态环境 ,改革土地政策 ,走可持续发展的道路。     

试论孝德教育的源起和产生

孝德源起于原始社会以血缘为基础的自然亲情、尊祖祭祖的宗教情怀和氏族养老尊老的古老传统.孝德教育的产生经历了漫长的发展过程,其中所包含的"尊祖祭祖教育"和"尊老养老教育"均可追溯到原始社会.孝德教育产生于西周.西周的孝德教育已经包含学校教育、祭祖仪式、"乡饮酒礼"、视学制度及"释奠礼"、朝廷训俗、采风易俗等诸多教育形式,其中,祭祖是西周孝德教育最主要的形式.孝德教育在西周产生是由当时"家国一体"的社会结构所决定的.     

“小农”概念的界定及其量化研究

目前学术界给＂小农＂一词所下的各种定义,一般都是对其主体进行直观的描述和概括,而缺乏＂量的规定性＂。小农经济形态的变化,既受不同历史条件下社会生产力发展水平的制约,又受不同国家和不同民族消费需求弹性的影响,但其上限应由农民家庭劳动力的独立经营能力决定,下限由维持一个农民家庭最基本的生存需要决定。我国实行高度分散的家庭承包经营形式,已经超出了一个标准的小农计量单位所允许的最低限度,尚不足以使绝大多数农户过上温饱舒适的小康生活,它所具有的自我激励作用十分有限,必须重新塑造现代农业主体,发展适度规模经营。