What ‘works’ when retracing sample members in a qualitative longitudinal study?

Attrition represents a significant obstacle to overcome in any longitudinal research project. It is, perhaps, most keenly felt when the data collected are from a qualitative study, since, unlike quantitative longitudinal research, weighting factors cannot be applied to ‘correct’ for any biases in the achieved sample and even a small number of ‘lost’ respondents can equate to a large percentage of the original sample. It is perhaps because of qualitative longitudinal research’s (QLR) reliance on, generally speaking, smaller samples that few have been able to shed much light on which re-contacting procedures are associated with achieving higher rates of retention. In this article, using data from a fifth sweep of a larger but particularly challenging cohort of 199 former probationers, we explore the strategies which helped us maintain high levels of retention in a QLR study. The article contains many practical suggestions which others planning or undertaking similar studies may find useful.     

关于当前我国国外马克思主义研究的批判性反思

当前我国国外马克思主义研究存在着三种值得注意的倾向,即把国外马克思主义概念和西方马克思主义概念不加区分地加以使用,追踪研究的热潮和对经典西方马克思主义理论研究的冷落形成鲜明对比,不能很好地处理国外马克思主义研究同中国马克思主义理论研究之间的关系。对上述问题进行批判性的考察,实现价值立场和研究方法的双重转换,有助于推进我国国外马克思主义的深入研究。     

Time to Diagnosis: Accounting for Differential Endpoint Follow-up in Multi-Cohort Studies

Cox regression is widely used to analyze discrete survival time data. Differential endpoint follow-up across sub-cohorts where distribution of a covariate varies may cause typical estimators to be biased or inefficient. We demonstrate that with Cardiovascular Health Study data for incident type 2 diabetes. Two cohorts with extremely different race distribution have differential follow-up for fasting glucose levels. We study various scenarios of Cox regression. We suggest an alternative approach, Poisson generalized estimating equations with an offset to accommodate the differential follow-up. We use simulations to contrast the methods.     

Semiparametric log-linear regression for longitudinal measurements subject to outcome-dependent follow-up

A common problem for longitudinal data analyses is that subjects follow-up is irregular, often related to the past outcome or other factors associated with the outcome measure that are not included in the regression model. Analyses unadjusted for outcome-dependent follow-up yield biased estimates. We propose a longitudinal data analysis that can provide consistent estimates in regression models that are subject to outcome-dependent follow-up. We focus on semiparametric marginal log-link regression with arbitrary unspecified baseline function. Based on estimating equations, the proposed class of estimators are root n consistent and asymptotically normal. We present simulation studies that assess the performance of the estimators under finite samples. We illustrate our approach using data from a health services research study.     

世博资源及其后续效应利用研究

中国2010年上海世界博览会自筹办和举办以来,已经产生多方面的重大影响,“世博后”仍将持续发挥其后续效应。在全面梳理世博物质资源和非物质资源的基础上,迫切需要系统分析世博资源后续利用的方式和途径,广泛挖掘世博科技成果在未来城市发展中的应用领域,努力寻找延续和放大世博后续效应的主要抓手,以全面推动上海“四个中心”和现代化国际大都市建设的战略进程,初步构建全球城市的功能体系和基本框架。     

Sample size calculation for logrank test and prediction of number of events over time

We review and compare existing methods for sample size calculation based on the logrank statistic and recommend the method of Lakatos for its accuracy and flexibility in allowing time-dependent rates of event, loss to follow-up, and noncompliance. We extend the Lakatos method to allow a general follow-up scheme, to handle non-inferiority tests, and to predict the number of events over calendar time. We apply the Lakatos method to the simple nonproportional hazard situation of delayed treatment effect to facilitate the comparison of different weighting methods and to evaluate the performance of the maximum combination tests. We use simulation studies to confirm the validity of the Lakatos method and its extensions.     

对政治性新闻发布会中后续问题的探究——以英国政府新闻发布会为例

对记者来说,新闻发布会给他们提供了一个让政客对自己言行负责的机会,这也是新闻业对于民主政治的贡献。通过提出后续问题,记者能够对政客们模糊的回答进行追问,更好地起到自己社会监督人的作用。文章通过对英国政府的5个新闻发布会进行分析,着重研究后续问题与记者先前问题和政客先前回答的关系,以及后续问题在新闻发布会上作用的分类,也是对先前他人对于后续问题所做的有关研究做一些补充,以求加深对于新闻发布会中后续问题的理解。     

Nonparametric Comparison for Multivariate Panel Count Data

Multivariate panel count data often occur when there exist several related recurrent events or response variables defined by occurrences of related events. For univariate panel count data, several nonparametric treatment comparison procedures have been developed. However, it does not seem to exist a nonparametric procedure for multivariate cases. Based on differences between estimated mean functions, this article proposes a class of nonparametric test procedures for multivariate panel count data. The asymptotic distribution of the new test statistics is established and a simulation study is conducted. Moreover, the new procedures are applied to a skin cancer problem that motivated this study.     

湖南省退耕还林工程后续政策探讨

湖南省自2000年开展退耕还林试点,2002年全面实施退耕还林工程以来,取得了良好的生态、经济和社会效益。但在退耕还林的过程中也出现了一些问题,如：补偿政策、工程管理、后续产业培育等。文章据此提出了完善湖南省退耕还林工程的后续政策建议。     

强化干预代谢综合征改变心脑血管事件发生风险的纵向随访研究：社区人群心脑血管事件前瞻性研究系列之四

目的了解药物综合干预代谢综合征（MS）是否可以改变发生心脑血管事件的风险。方法采用随机整群抽样南宁市两个社区的1215人符合纳入标准为本次综合干预治疗的研究对象,随机分为强化干预组和对照组。强化干预组人群按照是否患有MS及其相关疾病、疾病前状态（包括高血压、血压前期、肥胖、超重、糖尿病、糖耐量减退、血脂异常）等分别采取不同的强化治疗方案进行干预;对照组人员维持志愿就诊和志愿服药的正常医疗状态,每年随访1次,按WHO—MONICA方案心血管病事件（CVD）的诊断标准登记本年度发生的CVD和死亡事件。结果前瞻性随访研究43．5个月后：①经比较对照组中MS亚组与非MS亚组,MS患者发生心脑血管事件比非MS显著增高（P=-0．02）;②经比较干预组中MS亚组与非MS亚组,干预后MS心脑血管事件下降明显,MS患者发生心脑血管事件与非MS相比无差异（P〉0．05）;③经比较干预和对照两组MS亚组之间心脑血管事件的发生率,干预组为2．7％,对照组为10．1％,差异显著（P=0．03,OR值=4．01,95％CL：1．07—15．10）;两组非MS亚组之间心脑血管事件的发生率分别为2.3％和4．2％,无显著性差异（P=0．12）。结论药物综合干预代谢综合征（MS）可以改变发生心脑血管事件的风险,与对照相比干预后风险降低了约4倍。