Random Effects Misspecification Can Have Severe Consequences for Random Effects Inference in Linear Mixed Models

There has been considerable and controversial research over the past two decades into how successfully random effects misspecification in mixed models (i.e. assuming normality for the random effects when the true distribution is non‐normal) can be diagnosed and what its impacts are on estimation and inference. However, much of this research has focused on fixed effects inference in generalised linear mixed models. In this article, motivated by the increasing number of applications of mixed models where interest is on the variance components, we study the effects of random effects misspecification on random effects inference in linear mixed models, for which there is considerably less literature. Our findings are surprising and contrary to general belief: for point estimation, maximum likelihood estimation of the variance components under misspecification is consistent, although in finite samples, both the bias and mean squared error can be substantial. For inference, we show through theory and simulation that under misspecification, standard likelihood ratio tests of truly non‐zero variance components can suffer from severely inflated type I errors, and confidence intervals for the variance components can exhibit considerable under coverage. Furthermore, neither of these problems vanish asymptotically with increasing the number of clusters or cluster size. These results have major implications for random effects inference, especially if the true random effects distribution is heavier tailed than the normal. Fortunately, simple graphical and goodness‐of‐fit measures of the random effects predictions appear to have reasonable power at detecting misspecification. We apply linear mixed models to a survey of more than 4 000 high school students within 100 schools and analyse how mathematics achievement scores vary with student attributes and across different schools. The application demonstrates the sensitivity of mixed model inference to the true but unknown random effects distribution.     

中国沿海地区经济结构变动对海洋环境的影响

中国沿海经济结构的研究对海洋环境的发展意义重大,然而二者之间的定量关系及内在机理尚不完全清楚。以2007-2016年为研究时段,我国沿海11省(区、市)为研究区域,借助固定效应以及门槛模型,测度经济结构变动与海洋环境之间的关系。结果表明:①在经济结构中产业结构(-0.099)对海洋的弹性系数最大,其次是经济增速(-0.058),投资对象为正向影响,但不显著;非经济结构中,技术进步(0.052)的弹性系数最大,其中环境规制(-0.045)、人口规模(-0.045)抑制海洋环境的改善。②区域对比北部、东部海洋经济圈产业结构对海洋环境起抑制作用,另外,东部海洋经济圈环境规制、人口规模与海洋环境水平呈明显的负相关性;南部海洋经济圈相对于其他两个区域,结果不显著。③将产业结构、技术进步作为门槛变量,在各自的作用下分别存在双重门槛和单一门槛。产业结构门槛值为0.533、0.462,仅河北,福建未跨越第二门槛;科研能力门槛值为40,仅河北、福建、海南未跨过门槛值。因此,应适度调整产业结构,注重经济增长的质量,合理控制城镇人口的流动,积极鼓励科研创新,实现经济与海洋环境协调发展。     

Do news shocks increase capital utilization?

Using the workweek of capital as a measure of capital utilization, we empirically test whether news shocks actually increase capital utilization. To this end, by estimating a panel VAR on two-digit manufacturing data identifying news shocks as innovations to stock returns orthogonal to the variations in current-period TFP growth, we find the positive response of capital utilization to news shocks. Moreover, to explain the positive response of capital utilization to news shocks in terms of plant-level investment behavior, we propose a heterogeneous plant model that combines the fixed cost of capital adjustment and an endogenous capital utilization choice. With the presence of fixed costs, except for the plants that have recently adjusted capital stock, news shock shortens the effective time horizon of currently installed capital stock and increases capital utilization. When the model economy is calibrated to match the salient features of the plant-level investment rate distribution, the economy generates a news-driven positive response of capital utilization.     

Earnings management of initial public offering firms: evidence from regulation changes in China

Discretionary current accruals of Chinese initial public offering (IPO) firms decreased after the abolition of fixed‐price offering systems that directly linked offering price to reported earnings. Results suggest IPO firms that decrease managerial ownership manage earnings upward during the fixed‐price offering period, but this relationship disappeared after the introduction of a book‐building system. We also find that bank debt is negatively related to discretionary current accruals during the fixed‐price offering period, but no relation exists for the book‐building period. Leverage has a significant positive relationship with earnings management. However, this finding is potentially attributable to nonoffering price objectives or endogeneity biases.     

全球经常项目失衡影响因素的实证研究

近年来,全球经常项目失衡问题成为经济研究者、国际机构和各国中央银行经济学家以及商务经济研究报告竞相研究的热点问题。本文利用全球范围内56个国家或地区1980年至2005年的数据,针对影响经常项目的多种因素进行实证研究,结果表明经常项目与政府财政收支、资本形成率以及开放程度等因素密切相关。在当前全球经济增速放缓的形势下,只有通过有效的国际经济政策协调才能促进全球经常项目失衡问题的有序解决。     

固定资产增值税在现金流量表中的列示

我国自2009年1月1日起,允许全国范围内的所有增值税一般纳税人抵扣其新购进设备所含的进项税额。但是对于固定资产增值税的报表列示,尤其在现金流量表中的列示,无论是准则还是各项规定则未涉及。本文通过对固定资产增值税在现金流量表主表和补充资料中的填列项目的简要分析,辅之以实例阐述了固定资产增值税在现金流量表中应如何列示。     

行业标准化对中国进出口贸易的影响研究

以1993~2008年中国钢铁、煤炭、服装、食品加工、家电、机械制造六个行业的行业标准数目为基础,利用面板数据变截据模型分析行业标准化对进出口贸易的总体影响,通过面板数据变系数模型分析行业标准化对其进出口贸易额的影响。结果表明,我国的行业标准化对进出口贸易均存在正面影响,行业标准对钢铁、煤炭行业的进出口及对家电的出口均产生负面影响,对服装、食品加工、机械制造及家电的出口均产生正面影响。     

Strategic product showcasing mode of E-commerce live streaming

E-commerce live streaming can considerably help brands improve sales dynamics, but it is multiple dilemmas in choosing suitable e-commerce live streaming product showcasing modes. To address the multiple dilemmas, we first employ the Stackelberg game to depict three e-commerce live streaming product showcasing modes: brand self-live streaming, influencer-led live streaming mixture, and influencer-led special live streaming. Second, we analyze the relationship between choices and game parameters, including live streaming stimulus sensitivity, unit service quality improvement cost, and service sensitivity. Meanwhile, through the comparative analysis of the three modes, we get the optimal threshold of each mode. Last, we conduct a case study comparing Chinese apparel and accessories brands Hodo and RUANS to verify the above relations. The results suggest that: (i) the more sensitive consumers are to live streaming stimulus, the more beneficial it is for the brand manufacturer to employ special live streaming, while the increase in unit service quality improvement cost will harm the brand manufacturer; (ii) the fixed participation fee determines the choice of e-commerce live streaming product showcasing modes; (iii) e-commerce live streaming product showcasing modes can help brands to optimize their decision-making.     

Informal pay gaps in good and bad times: Evidence from Russia

Informal work is traditionally large in Russia and has further increased in the recent years. We explore the implications of this shift in terms of wage dynamics. Our characterization is based on the estimation of informal pay gaps at the mean and along the wage distribution, relying on the Russian Longitudinal Monitoring Survey for 2003–2017. Our approach comprises three original features: we rely on unconditional quantile effects of informality, we incorporate quantile-specific fixed effects using a tractable approach, and we suggest a treatment of the incidental parameter bias. Over the whole period, informal wage penalties are relatively small and do not suggest heavily segmented labor markets, even at low wage levels. Yet, in the past decade, a substantial negative selection into informal employment and self-employment has taken place, on average and especially at low earnings. Economic downturns and labor market policies have likely contributed to the shakeout of less productive workers in the formal sector, making the low-tier informal sector more of a last resort.     

Separating what we eat from where: Measuring the effect of food away from home on diet quality

Many argue that food away from home (FAFH) is a contributing factor to the obesity epidemic, showing that body mass index and consumption of FAFH are positively correlated. However, correlation analyses using a simple regression approach, such as the Ordinary Least Squares (OLS), do not prove that FAFH causes weight gain. We use a first-difference estimator to establish a causal relationship between FAFH and dietary intakes. Using dietary recall data from the 2003–2004 National Health and Nutrition Examination Survey and the 1994–1996 Continuing Survey of Food Intakes by Individuals, we find that FAFH does indeed increase caloric intake and reduce diet quality, but that the effect is smaller than if estimated using OLS. Thus, models based on associations are likely biased upward, as much as 25% by our estimates.