Keeping things simple: why the Human Development Index should not diverge from its equal weights assumption

Using a range of statistical criteria rooted in Information Theory we show that there is little justification for relaxing the equal weights assumption underlying the United Nation’s Human Development Index (HDI) even if the true HDI diverges significantly from this assumption. Put differently, the additional model complexity that unequal weights add to the HDI more than counteracts the improvement in goodness-of-fit. This suggests that, in some cases, there may be limited validity in increasing the complexity of a range of other composite sustainability indices.     

The micro consequences of macro-level social transition: how did Russians survive in the 1990s?

Using panel data from the Russian Longitudinal Monitoring Survey (RLMS), we investigate the possible links between the Russian mortality crisis of the 1990s and social transition that followed the collapse of the Soviet Union. The results of the analysis demonstrate that Russians’ life chances and their psychological resources and well-being were deteriorated during the transition in the 1990s. The deterioration of life chances and psychological resources and well-being, in conjunction with the high-risk lifestyle of many Russians, increased their risks of dying both directly and indirectly, through a negative impact on their health. This work was completed before the first author started to work in the Centers for Disease Control and Prevention. The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.     

武汉市残疾人就业状况调查及保障机制研究

本文以武汉市为样本空间,通过文献资料法、实地考察法、访谈调查法、问卷调查法、比较分析法和政府取样等方法对武汉市残疾人的生存现状进行调研。通过数学统计方法对调查结果分析发现,残疾人的就业状况和教育水平、年龄、职业技能培训、就业途径、社会态度等有重要的相关性,据此分析提出了保障残疾人就业的几点建议。     

完善创业板退市制度真正建立优胜劣汰的市场机制

进一步完善创业板退市制度,健全市场退出机制,是创业板市场持续、稳定、健康发展的重要制度保障,不但有利于增强对劣质公司的威慑力和制约力,提升创业板公司整体质量,强化市场约束,净化市场环境,从而真正建立优胜劣汰的市场机制,而且有利于引导投资者牢固树立审慎的投资理念,进行更理性的投资,切实增强投资者的风险意识,警惕创业板的退市风险,从而维护投资者尤其是广大中小投资者的合法权益。通过考察海外证券市场退市制度改革的发展趋势,阐述我国创业板退市制度的主要特点,然后分析了我国证券市场现行退市制度存在的主要弊端,最后有针对性地提出了完善我国创业板退市制度、健全市场退出机制的政策建议以及相关的配套措施。     

Multiple imputation of a randomly censored covariate improves logistic regression analysis

Randomly censored covariates arise frequently in epidemiologic studies. The most commonly used methods, including complete case and single imputation or substitution, suffer from inefficiency and bias. They make strong parametric assumptions or they consider limit of detection censoring only. We employ multiple imputation, in conjunction with semi-parametric modeling of the censored covariate, to overcome these shortcomings and to facilitate robust estimation. We develop a multiple imputation approach for randomly censored covariates within the framework of a logistic regression model. We use the non-parametric estimate of the covariate distribution or the semi-parametric Cox model estimate in the presence of additional covariates in the model. We evaluate this procedure in simulations, and compare its operating characteristics to those from the complete case analysis and a survival regression approach. We apply the procedures to an Alzheimer's study of the association between amyloid positivity and maternal age of onset of dementia. Multiple imputation achieves lower standard errors and higher power than the complete case approach under heavy and moderate censoring and is comparable under light censoring. The survival regression approach achieves the highest power among all procedures, but does not produce interpretable estimates of association. Multiple imputation offers a favorable alternative to complete case analysis and ad hoc substitution methods in the presence of randomly censored covariates within the framework of logistic regression.