Aggregate consumption functions for India: A cointegration analysis under structural changes, 1919-86

This paper extends cointegration methodology to include the effect of possible structural changes on aggregate consumption behaviour in India during 1919-86. The only cointegrated relation is found to be a dynamic linear regression of lag order two, with 1944 as the year in which structural change began. The estimated short-run marginal propensity to consume (MPC) is greater than the long-run MPC. The estimates of the MPC are different from previous estimates for the Indian economy based on conventional econometrics. The initial year of structural change has been selected by extending the method of Perron and that of Zivot and Andrews.     

经济政策不确定性如何影响金融市场间的流动性协同运动？——基于中国金融周期的视角

金融市场间流动性出现高协同运动是发生危机传染的重要表现之一，因此，针对流动性动态联动效应的研究显得极为重要。本文基于中国金融市场数据测算了2003-2018年间我国股市、债市流动性，并对Colacito等（2011）的混频数据抽样动态条件相关系数模型（DCC-MIDAS）进行了扩展，同时从金融周期视角出发，运用扩展后的模型考察了经济不确定性在不同时间区间内对于流动性波动率和相关性是否存在不同的作用效果。研究结果表明，相较于单因子混频模型，引入经济政策不确定性的多因子混频模型可以更好地捕捉我国股债两市相关性的动态变化；同时，经济政策不确定性的提高会降低股债两市流动性的正相关性，但这一作用效果会在金融周期的拐点处转为加强两者的正相关性。本文不仅为讨论股债两市联动效应提供了流动性的新视角，也为金融市场风险监管提供了重要的参考依据。     

Bayesian regression model for recurrent event data with event-varying covariate effects and event effect

In the course of hypertension, cardiovascular disease events (e.g. stroke, heart failure) occur frequently and recurrently. The scientific interest in such study may lie in the estimation of treatment effect while accounting for the correlation among event times. The correlation among recurrent event times comes from two sources: subject-specific heterogeneity (e.g. varied lifestyles, genetic variations, and other unmeasurable effects) and event dependence (i.e. event incidences may change the risk of future recurrent events). Moreover, event incidences may change the disease progression so that there may exist event-varying covariate effects (the covariate effects may change after each event) and event effect (the effect of prior events on the future events). In this article, we propose a Bayesian regression model that not only accommodates correlation among recurrent events from both sources, but also explicitly characterizes the event-varying covariate effects and event effect. This model is especially useful in quantifying how the incidences of events change the effects of covariates and risk of future events. We compare the proposed model with several commonly used recurrent event models and apply our model to the motivating lipid-lowering trial (LLT) component of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) (ALLHAT-LLT).     

Robust estimation of a dynamic spatio-temporal model with structural change

We postulate a dynamic spatio-temporal model with constant covariate effect but with varying spatial effect over time and varying temporal effect across locations. To mitigate the effect of temporary structural change, the model can be estimated using the backfitting algorithm embedded with forward search algorithm and bootstrap. A simulation study is designed to evaluate structural optimality of the model with the estimation procedure. The fitted model exhibit superior predictive ability relative to the linear model. The proposed algorithm also consistently produced lower relative bias and standard errors for the spatial parameter estimates. While additional neighbourhoods do not necessarily improve predictive ability of the model, it trims down relative bias on the parameter estimates, specially for spatial parameter. Location of the temporary structural change along with the degree of structural change contributes to lower relative bias of parameter estimates and in better predictive ability of the model. The estimation procedure is able to produce parameter estimates that are robust to the occurrence of temporary structural change.     

Conditional time-dependent nonparametric estimators with an application to healthcare production function

ABSTRACT

By using the probabilistic framework of production efficiency, the paper develops time-dependent conditional efficiency estimators performing a non-parametric frontier analysis. Specifically, by applying both full and quantile (robust) time-dependent conditional estimators, it models the dynamic effect of health expenditure on countries’ technological change and technological catch-up levels. The results from the application reveal that the effect of per capita health expenditure on countries’ technological change and technological catch-up is nonlinear and is subject to countries’ specific income levels.     

ICT投资、互联网普及和全要素生产率

本文使用DEA-Malmquist指数方法对2002-2012年我国分行业全要素生产率、技术效率与技术进步进行测算,并基于我国地区投入产出表构建了ICT资本投入强度。在此基础上,本文就ICT投资对生产率的影响进行了实证检验。研究发现,ICT投资对全要素生产率提升具有积极作用,并且主要通过ICT投资促进技术效率提升实现。面板门限回归模型的结果显示,只有达到一定互联网普及率时,ICT投资促进技术效率提升的作用才显现,并在高互联网普及率时进一步增强;但在高互联网普及率下,ICT 投资对技术进步存在抑制作用,在全要素生产率层面表现为ICT 投资的促进作用消失。因此,现实的ICT 投资应重视通过信息化管理提升行业资源的有效利用能力,以最大化技术效率对全要素生产率的贡献;应充分考虑不同行业和地区的互联网普及程度,以深度激发“连接经济”对于释放ICT效能的互补性作用;还应注意配套相应产业政策,以减轻互联网发展对技术进步的阻碍作用。     

A Multistate Transition Model for Osteoarthritis Pain Change

Pain severity of knees is assessed using an ordinal scale in patients with musculoskeletal diseases and often changes over time. Assessment of the effect of a particular risk factor on the change in pain severity will shed light on our understanding of biological mechanisms and provide guidance for rational clinical intervention for recurrent pain. The multistate transition model allows transitions between several different states of pain severity and estimates the transitional intensity using an extension of the Cox proportional hazards model. Using data from a longitudinal study, we applied this model to assess the relation of two psychological factors to the change in knee pain severity over time among patients with osteoarthritis and demonstrated that the multistate transition model can be a valuable tool for rheumatic disease studies.     

Embedded experiments in repeated and overlapping surveys

Summary.  Statistical agencies make changes to the data collection methodology of their surveys to improve the quality of the data collected or to improve the efficiency with which they are collected. For reasons of cost it may not be possible to estimate the effect of such a change on survey estimates or response rates reliably, without conducting an experiment that is embedded in the survey which involves enumerating some respondents by using the new method and some under the existing method. Embedded experiments are often designed for repeated and overlapping surveys; however, previous methods use sample data from only one occasion. The paper focuses on estimating the effect of a methodological change on estimates in the case of repeated surveys with overlapping samples from several occasions. Efficient design of an embedded experiment that covers more than one time point is also mentioned. All inference is unbiased over an assumed measurement model, the experimental design and the complex sample design. Other benefits of the approach proposed include the following: it exploits the correlation between the samples on each occasion to improve estimates of treatment effects; treatment effects are allowed to vary over time; it is robust against incorrectly rejecting the null hypothesis of no treatment effect; it allows a wide set of alternative experimental designs. This paper applies the methodology proposed to the Australian Labour Force Survey to measure the effect of replacing pen-and-paper interviewing with computer-assisted interviewing. This application considered alternative experimental designs in terms of their statistical efficiency and their risks to maintaining a consistent series. The approach proposed is significantly more efficient than using only 1 month of sample data in estimation.     

卖空机制能促进企业全要素生产率增长吗?

提高企业全要素生产率是实现我国经济高质量发展的关键。本文在理论提出卖空机制“信息增益效应”和“压力减损效应”的基础上,采用双重差分方法实证检验卖空机制与全要素生产率增长之间的关系。研究发现,卖空交易机制显著促进了企业全要素生产率增长,具体表现为放松卖空管制后上市公司的技术、技术效率、规模效率和配置效率的变化率均有显著提升。渠道检验发现,卖空机制对全要素生产率增长的提升效应主要通过畅通信息传递、优化市场资源配置和提高公司治理水平发挥作用。此外,较之于国有企业,民营企业中卖空机制对生产率增长的促进效应表现得更为强烈。本研究推动了微观金融和宏观经济增长的融合,并为资本市场改革助力经济高质量发展战略提供了微观经验证据。     

中国大蒜电子交易市场与现货市场波动溢出效应研究——基于二元VAR-GARCH-BEKK模型

本文采用二元VAR-GARCH-BEKK模型,对中国大蒜现货市场和电子交易市场间的波动溢出效应进行了分析,研究发现:既存在现货市场向电子交易市场单向的波动溢出效应,也存在电子交易市场向现货市场的单向波动溢出效应,同时两个市场间还存在着双向的波动溢出效应,并且大蒜电子交易市场向现货市场的波动溢出效应要强于现货市场向电子交易市场的波动溢出效应,两个市场间的波动溢出效应主要是由电子交易市场向现货市场的溢出。     

技能溢价源于技术进步偏向性吗？

 内生经济增长理论向来关注技术进步对经济增长的贡献,但现代研究却普遍忽视技术进步对异质性要素发展可能产生的偏向性影响,特别是技术进步能否呈现技能偏向性并引致不同类型劳动者报酬分化问题。本文利用双层嵌套型CES生产函数和非线性似不相关方法估计中国技能溢价水平,研究发现我国资本和劳动替代弹性小于1而技能和非技能劳动替代弹性大于1,技术进步偏向性及技能和非技能劳动的替代效应明显,利用技术进步偏向性模型模拟的数据与真实值无明显差异,印证技能溢价源于偏向型技术进步且偏向性效应不断强化。同时,回归方法检验结果也发现,技术进步偏向性对技能溢价正向效应显著,验证出我国技能溢价现象主要是源于技术进步偏向性作用的结果。     

Investigating the effects of hunting on the survival of British pigeons and doves by analysis of ringing recoveries

Recent changes in British hunting legislation have protected the stock dove Columba oenas since 1 October 1982, and removed protection from the collared dove Streptopelia decaocto after 1 April 1977; the woodpigeon Columba palumbus has remained legal quarry throughout. Ringing recoveries offer a means of comparing annual survival rates before and after the change in legislation. Care is needed in the construction of the recovery matrices to remove inhomogeneities in the data and ensure that each 'year' runs from the day of legislative change. Annual survival rates were estimated by maximum likelihood using multinomial models conditioned on the recoveries; there was no evidence of age- or time-related variation in reporting rates. The annual survival rate of the stock dove was constant, at 54 +/- 3%. For both the collared dove and the woodpigeon, estimates of survival rates in the first year after ringing were not consistent between birds ringed as young and those ringed as adults, but nevertheless averaged less before 1977 than after 1977; annual survival rates of birds that survived the first year after ringing did not differ between time periods, and were 64 +/- 2% for the collared dove and 61 +/- 2% for the woodpigeon. The proportion of recoveries reported shot or trapped was only 14% for the collared dove, compared with 79% for the woodpigeon, and remained constant before and after 1977 for both species; in the case of the stock dove, the proportion reported shot or trapped before and after 1982 fell from 70% to 34%. The change in quarry status had no effect on annual survivorship or population size of either the stock dove or the collared dove, while the woodpigeon has increased regularly in abundance despite heavy shooting.     

The effectiveness of coach turnover and the effect on home team advantage,team quality and team ranking

The effectiveness of coach turnover on team performance is widely discussed in the literature due to the indirect impact of a team's performance on a club's revenues. This study examines the effect of coach turnover within a competition season by focusing on the change in team quality and the change in home team advantage under the new coach. The change in team quality or home team advantage can vary according to the team (team specific) or might be an independent quantity (non-team specific). We estimated nine possible regression models, given no change, team-specific change and non-team-specific change in quality or home team advantage. The data are the match results of Belgian male soccer teams playing in the highest national division during seven seasons. Results point to a team-specific effect of a new coach on a team's quality. This article further contributes by evaluating the new coach's success with regard to whether his ability to improve team quality also results in a better position of the team in the final ranking. A new coach will be able to improve the ranking of the team if the improved team quality under the new coach renders a positive team quality.     

Detection of biomass change in a Norwegian mountain forest area using small footprint airborne laser scanner data

Different approaches for estimation of change in biomass between two points in time by means of airborne laser scanner data were tested. Both field and laser data were collected at two occasions on 52 sample plots in a mountain forest in southeastern Norway. In the first approach, biomass change was estimated as the difference between predicted biomass for the two measurement occasions. Joint models for the biomass at both occasions were fitted using different height and density variables from laser data as explanatory variables. The second approach modelled the observed change directly using the change in different variables extracted from the laser data as explanatory variables. In the third approach we modelled the relative change in biomass. The explanatory variables were also expressed as relative change between measurement occasions. In all approaches we allowed spline terms to be entered. We also investigated the aptness of models for which the residual variance was modeled by allowing it to be proportional to the area of the plot on which biomass was assessed. All alternative models were initially assessed by AIC. All models were also evaluated by estimating biomass change on the model development data. This evaluation indicated that the two direct approaches (approach 2 and 3) were better than relying on modeling biomass at both occasions and taking change as the difference between biomass estimates. Approach 2 seemed to be slightly better than approach 3 based on assessments of bias in the evaluation.     

Effect of Dependency in Systems for Multivariate Surveillance

Systems for multivariate on-line surveillance (e.g., outbreak detection) are investigated. Optimal systems for statistical surveillance are based on likelihood ratios. Three systems are compared: based on each marginal density, based on the joint density, and based on the Hotelling's T2. The effect of dependency between the monitored processes is investigated, and the effect of correlation between the change times. When the first change occurs immediately, the three methods give similar delay of an alarm, in the situation with independency. For late changes, T2 has the longest delay, both for independent processes and for processes with a positive covariance.     

传统产业转型升级的政策变迁及实施效果——中国纺织产业的个案研究

从"政策变迁"和"实施效果"两个视角切入,在全面梳理中国纺织产业转型升级已有政策的基础上,基于文本计量分析法从四个维度研究中国纺织产业转型升级政策的历史变迁及主要特征,应用"目标达成"模式并结合模糊优选模型对政策效果进行评价。研究表明:中国纺织产业转型升级政策表现出比较明显的"周期性"、"专用性"、"治理性"和"约束性",而"行业整合"和"产业培育"类政策相对较少,并且指导性和可操作性亟待加强;中国纺织产业转型升级政策颁布的前五年实际效果一般,但是近年来稳步上升;不同政策工具对具体指标的影响程度、实际效果及持续性存在差异。     

Decomposition of the main effects and interaction term by using orthogonal polynomials in multiple non symmetrical correspondence analysis

The multiple non symmetric correspondence analysis (MNSCA) is a useful technique for analyzing a two-way contingency table. In more complex cases, the predictor variables are more than one. In this paper, the MNSCA, along with the decomposition of the Gray–Williams Tau index, in main effects and interaction term, is used to analyze a contingency table with two predictor categorical variables and an ordinal response variable. The Multiple-Tau index is a measure of association that contains both main effects and interaction term. The main effects represent the change in the response variables due to the change in the level/categories of the predictor variables, considering the effects of their addition, while the interaction effect represents the combined effect of predictor categorical variables on the ordinal response variable. Moreover, for ordinal scale variables, we propose a further decomposition in order to check the existence of power components by using Emerson's orthogonal polynomials.     

Estimation of hazard of death in vertically transmitted HIV-1-infected children for doubly censored failure times and fixed covariates

This work estimates the effect of covariates on survival data when times of both originating and failure events are interval-censored. Proportional hazards model [16] along with log-linear models was applied on a data of 130 vertically infected HIV-1 children visiting the paediatrics clinic. The covariates considered for the analysis were antiretroviral (ARV) therapy, age at diagnosis, and change in CD4+T cell count. Change in CD4+T cell count was the difference in the last and first count in non-ARV therapy group, while in the ARV therapy group the same was considered after the start of the treatment. Our findings suggest that children on ARV therapy had significantly lower risk of death (p<0.001). We further investigated the effect of age and change in CD4+T cell count on risk of death. These covariates exhibited a possible association with risk of death by both the procedures (p<0.0001). The effect of number of years under ARV therapy with diagnosis year as a confounding factor was directly related to longevity. The results obtained by the two procedures gave reasonable estimates. We conclude that when the lengths of intervals are narrow, we can opt for parametric modeling which is less computationally intensive.     

基于IO-SDA模型的浙江省外贸隐含碳影响因素分析

 本文对浙江省2002—2009年外贸过程中的含碳量进行了测量,并分解其变化的影响因素。研究表明：在此期间进出口内涵碳都有较大幅度的增加,CO2贸易条件整体尚佳但趋势不容乐观;贸易规模效应在所有影响因素中起着决定性作用,这也是2009年排放量出现下降的原因;能源效率的改善在一定程度上抑制了贸易含碳量的增加;出口结构效应与进口结构效应存在较大不同;而中间投入效应与单位能源碳排放效应的影响值都非常小。     

Coordinate-free analysis of trends in British social mobility

This paper is intended to make a contribution to the ongoing debate about declining social mobility in Great Britain by analyzing mobility tables based on data from the 1991 British Household Panel Survey and the 2005 General Household Survey. The models proposed here generalize Hauser's levels models and allow for a semi-parametric analysis of change in social mobility. The cell frequencies are assumed to be equal to the product of three effects: the effect of the father's position for the given year, the effect of the son's position for the given year, and the mobility effect related to the difference between the father's and the son's positions. A generalization of the iterative proportional fitting procedure is proposed and applied to computing the maximum likelihood estimates of the cell frequencies. The standard errors of the estimated parameters are computed under the product-multinomial sampling assumption. The results indicate opposing trends of mobility between the two timepoints. Fewer steps up or down in the society became less likely, while more steps became somewhat more likely.