Household debt and financial assets: evidence from Germany, Great Britain and the USA

Summary.  We explore the determinants of debt, financial assets and net worth at the household level by using survey data for Germany, Great Britain and the USA. To identify which households are potentially vulnerable to adverse changes in the economic environment, we also explore the determinants of a range of measures of financial pressure: the probability that a household has negative net worth; the debt-to-income ratio; mortgage income gearing; the saving-to-income ratio. Our empirical findings suggest that the poorest and the youngest households are the most vulnerable to adverse changes in their financial circumstances.     

研发部门体制改革与企业创新行为——以A股制造业上市公司为例

结合沪深A股制造业上市公司年报数据,构建Tobit回归模型对企业研发行为进行影响因素分析和稳健性检验。结论发现,研发强度与企业规模、大股东持股比例、经营年限负相关,但与技术人员人数占比正相关;此外,销售毛利率、存货周转率、现金比率以及市销率、市净率等指标也明显左右着企业创新积极性的发挥。为此旨在透过研发部门体制改革推动企业创新发展,建议由传统龙头企业拆分设立研发型子公司,对新兴初创企业引入战略投资者;鼓励企业将生产、销售业务逐步外包,探索建立多元化内源性融资渠道;试点成立创新型创投、私募等专项基金,制定针对性财税政策扶持等。     

A growth mixture Tobit model: application to AIDS studies

This paper presents an alternative analysis approach to modeling data where a lower detection limit (LOD) and unobserved population heterogeneity exist in a longitudinal data set. Longitudinal data on viral loads in HIV/AIDS studies, for instance, show strong positive skewness and left-censoring. Normalizing such data using a logarithmic transformation seems to be unsuccessful. An alternative to such a transformation is to use a finite mixture model which is suitable for analyzing data which have skewed or multi-modal distributions. There is little work done to simultaneously take into account these features of longitudinal data. This paper develops a growth mixture Tobit model that deals with a LOD and heterogeneity among growth trajectories. The proposed methods are illustrated using simulated and real data from an AIDS clinical study.     

动态视角下中国城市群土地利用TFP测度及影响因素研究

提高城市群土地利用TFP对合理高效利用土地资源,协调好城市群经济发展、资源配置和环境保护具有重大理论和实践意义.文章运用DEA-Malmquist指数对2003—2016年动态视角下中国城市群土地利用TFP进行测度和时空演变分析,并利用Tobit回归模型对影响城市群土地利用TFP变化的因素进行深入研究.结果表明:从时间维度看,城市群土地利用TFP年均上升0.7％,城市群土地利用TFP增长由技术效率和技术进步"双核驱动",技术效率的提升主要与纯技术效率提升有关,规模效率是技术效率和土地利用TFP提升的瓶颈约束;从空间维度看,晋中、哈长、海峡西岸、中原、长江中游、北部湾、成渝、黔中、关中平原和兰西城市群土地利用TFP呈下降趋势,其余城市群土地利用TFP均呈上升趋势,且京津冀、呼包鄂榆、辽中南、长江三角洲、山东半岛和天山北坡城市群土地利用TFP增长为技术进步和技术效率"双核驱动";从影响因素看,人均GDP和年末金融机构人民币各项贷款余额对中国城市群土地利用TFP具有正向促进作用,城市财政支出占本市GDP的比重和人口密度具有负向阻碍作用.     

Composite Estimation for Single‐Index Models with Responses Subject to Detection Limits

We propose a semiparametric estimator for single‐index models with censored responses due to detection limits. In the presence of left censoring, the mean function cannot be identified without any parametric distributional assumptions, but the quantile function is still identifiable at upper quantile levels. To avoid parametric distributional assumption, we propose to fit censored quantile regression and combine information across quantile levels to estimate the unknown smooth link function and the index parameter. Under some regularity conditions, we show that the estimated link function achieves the non‐parametric optimal convergence rate, and the estimated index parameter is asymptotically normal. The simulation study shows that the proposed estimator is competitive with the omniscient least squares estimator based on the latent uncensored responses for data with normal errors but much more efficient for heavy‐tailed data under light and moderate censoring. The practical value of the proposed method is demonstrated through the analysis of a human immunodeficiency virus antibody data set.     

Modified maximum likelihood estimator under the Jones and Faddy's skew t-error distribution for censored regression model

It is well-known that classical Tobit estimator of the parameters of the censored regression (CR) model is inefficient in case of non-normal error terms. In this paper, we propose to use the modified maximum likelihood (MML) estimator under the Jones and Faddy''s skew t-error distribution, which covers a wide range of skew and symmetric distributions, for the CR model. The MML estimators, providing an alternative to the Tobit estimator, are explicitly expressed and they are asymptotically equivalent to the maximum likelihood estimator. A simulation study is conducted to compare the efficiencies of the MML estimators with the classical estimators such as the ordinary least squares, Tobit, censored least absolute deviations and symmetrically trimmed least squares estimators. The results of the simulation study show that the MML estimators work well among the others with respect to the root mean square error criterion for the CR model. A real life example is also provided to show the suitability of the MML methodology.     

长江经济带软件与信息技术服务业技术创新效率时空演变及影响因素研究

选取长江经济带软件与信息技术服务业相关数据,利用DEA-BCC模型测算软件与信息技术服务业技术创新效率,并借助自然断裂法和Tobit模型分析区域软件业技术创新效率时空演变特征及影响机理。从静态分析结果看,长江经济带软件业技术创新效率在研究期内呈现先升、后降、再升的螺旋上升态势。从动态分析结果看,技术进步是软件业技术创新效率提升的主要原因。软件业技术创新效率在空间分布上有明显的中间凹陷特征,各地区整体技术创新效率明显上升。科技创新水平、产业结构、对外开放水平、信息化水平、人口密度是影响长江经济带软件业技术创新效率的重要因素,且影响程度存在区域差异。     

湖南省农产品流通效率测度及其影响因素研究 ——基于DEA-Malmquist指数和Tobit模型

文章以2009—2018年湖南省13个地级市为研究对象,构建DEA-Malmquist指数模型对湖南省农产品流通效率进行静态和动态分析。结果显示:近年来湖南省农产品流通全要素生产率整体提升,但是除长沙、衡阳和岳阳外,其他地区的规模效率在逐步下降,技术效率提升不稳定。这表明农产品流通业投入产出结构不合理是制约湖南省农产品流通效率提升的主要因素,农产品流通业在技术创新与管理创新方面的缺乏也是抑制湖南省农产品流通效率提高的因素。采用Tobit模型考察农产品流通效率的影响因素,结果表明:资本和劳动力投入、基础设施建设水平、信息化水平和居民消费水平都在不同程度上影响湖南省农产品流通效率。因此,应加快湖南省农业结构调整步伐,以提升农业供给体系的整体质量和效率。     

网络视频实时在线评论用户认可度的影响因素

目前,网络视频实时在线评论激增带来的信息爆炸,使实时在线评论信息管理成为重要议题。以往对实时在线评论的研究多集中于个人行为结果方面,而缺乏对实时在线评论信息管理问题的关注;同时,现有视频网站对实时在线评论信息的管理也存在诸多局限。以爱奇艺视频网站热度榜中的电影为样本,基于信息质量维度框架并采用Tobit模型对实时在线评论用户认可度的影响因素进行研究,结果发现：实时在线评论的新颖性、相似性、情感倾向性和信息丰富性,均对实时在线评论的用户认可度存在显著影响,其中新颖性和相似性影响作用最大。视频网站可以据此进一步强化实时在线评论管理,改善用户的体验,保持用户的粘性。     

LEGISLATING LOVE: The Effect of Child Support and Welfare Policies on Father–child Contact

Reducing non-marital childbearing and making nonresidential fathers take greater responsibility for their children were identified as goals of numerous policy changes since the 1980s. Child-support award rates for children born to unmarried parents have been quite low historically, leading lawmakers to focus on increasing both award and payment rates for this group. Nonmarital fathers are also much less likely to have contact with their children. Although evidence suggests that policy efforts increase child support awards and receipt, the link between child support policies, child support outcomes, and father-child contact has received less attention. This paper uses data from the Survey of Income and Program Participation on children born between 1985–1997 to investigate the relationship between child-support award and receipt and the amount of contact that fathers have with their non-residential children. Since it is likely that both of these behaviors are, in part, determined by unobservable characteristics of the father, we estimate an instrumental variables Tobit model. The model is identified by our assumption that child support policy variables can impact child support awards and payments, but father-child contact cannot be directly legislated. Our results suggest that there are unintended, but desirable effects of child support establishment and collection. Policies to collect child support not only increase financial resources to families, but through their impact on payments increase visitation and contact between these children and their fathers. The estimated impact of receiving child support on contact is more than 27 days per year.An earlier version of this paper was presented at the Annual Meetings of the American Economic Association, Washington DC, January 2003 and the Annual Meetings of the Association of Public Policy and Management, November 2003. Support from NICHD Grant # HD30944 is gratefully acknowledged. We would like to thank Suzann Eshleman for excellent computer programming and James Scully for providing us with data on genetic testing laws.