Choice of estimand and analysis methods in diabetes trials with rescue medication

The analysis of clinical trials aiming to show symptomatic benefits is often complicated by the ethical requirement for rescue medication when the disease state of patients worsens. In type 2 diabetes trials, patients receive glucose‐lowering rescue medications continuously for the remaining trial duration, if one of several markers of glycemic control exceeds pre‐specified thresholds. This may mask differences in glycemic values between treatment groups, because it will occur more frequently in less effective treatment groups. Traditionally, the last pre‐rescue medication value was carried forward and analyzed as the end‐of‐trial value. The deficits of such simplistic single imputation approaches are increasingly recognized by regulatory authorities and trialists. We discuss alternative approaches and evaluate them through a simulation study. When the estimand of interest is the effect attributable to the treatments initially assigned at randomization, then our recommendation for estimation and hypothesis testing is to treat data after meeting rescue criteria as deterministically ‘missing’ at random, because initiation of rescue medication is determined by observed in‐trial values. An appropriate imputation of values after meeting rescue criteria is then possible either directly through multiple imputation or implicitly with a repeated measures model. Crucially, one needs to jointly impute or model all markers of glycemic control that can lead to the initiation of rescue medication. An alternative for hypothesis testing only are rank tests with outcomes from patients ‘requiring rescue medication’ ranked worst, and non‐rescued patients ranked according to final visit values. However, an appropriate ranking of not observed values may be controversial. Copyright © 2015 John Wiley & Sons, Ltd.     

PRODUCT MARKET REGULATION,FIRM SELECTION,AND UNEMPLOYMENT

This paper analyzes the effect of product market regulation (PMR) on unemployment in a search model with heterogeneous multiple‐worker firms. In our setup, PMR modifies the distribution of firm productivities, thereby affecting the equilibrium rate of unemployment. We distinguish between PMR related to entry costs and PMR that generates recurrent fixed costs. We find that: (i) higher entry costs raise the rate of unemployment mainly through our novel selection effect, (ii) higher fixed costs decrease unemployment through the selection effect and increase it through the competition effect analyzed in Blanchard and Giavazzi (2003, Quarterly Journal of Economics, 118, 879–907). Firm heterogeneity magnifies the impact of both types of regulatory costs. We propose econometric evidence consistent with the unemployment effects of sunk versus recurring costs.     

ARTIFICIAL STATES

We define artificial states as those in which political borders do not coincide with a division of nationalities desired by the people on the ground. We propose and compute for most countries in the world two measures of the degree to which borders may be artificial. One measures how borders split ethnic groups into two separate adjacent countries. The other measures the straightness of land borders, under the assumption the straight land borders are more likely to be artificial. We then show that these two measures are correlated with several measures of political and economic success.     

困顿中对教育的执着——探析梁漱溟在广东的教育思想与实践活动

20世纪20年代,国民大革命的浪潮冲刷了中国社会的每个角落,梁漱溟不断思索着中国未来的教育出路,在坚定了通过走乡村教育的道路来振兴中国的信念后,南下来粤,开始了广东乡治讲习所和广东第一中学的教育探索,为以后的乡村建设打下理论和实践的基础。     

重庆新闻文化资源综合使用状况调查

信息技术的飞速发展,引发了整个社会和人类观念的深刻变革,新媒体在社会各个领域扮演着越来越重要的角色,也对新闻文化资源的综合使用提出了新要求。重庆新闻文化资源的使用正朝着数字化方向迈进,但存在着信息整合度不高、检索有效性不强、技术运用有限等问题。这些问题的解决,需要加强技术攻关,有效整合资源,尤其应当依托“云计算”平台提高新闻文化资源的综合使用。     

大学英语的困惑与对策

随着《大学英语课程教学要求》的出台,新一轮的大学英语教学改革在全国推展开来。文章试图从历史、现状和将来三个时段来探讨大学英语的教改之路。     

大学新生词汇量及词汇运用能力调查探究

本调查以三所不同高校非英语专业本科新生为总体样本,运用抽样调查方法分别从三所高校按比例抽取样本,采取试卷测试和个别访谈相结合的形式,调查学生入学时词汇的初始状况,并利用数理统计方法得出学生词汇量。结果表明:1)非英语专业本科新生词汇量与教学大纲中规定掌握的词汇量尚有差距;2)重点院校新生词汇量比一般院校新生高出16.2%;3)学生在词汇领会基础上的运用能力仍显不足。对此分析,本文就如何提高词汇识别和运用能力提出了一些有益的建议。     

Epidemiological Associations between Gambling Behavior, Substance Use & Mood and Anxiety Disorders

Objective To compare gambling behaviors in a random sample of community residents with and without mental disorders identified by the Composite International Diagnostic Interview (CIDI).Method A large national community survey conducted by Statistics Canada included questions about problems arising from gambling activities as per the Canadian Problem Gambling Index (CPGI). We compared respondents within three gambling severity categories (non-problem, low severity and moderate/high severity gambling) across three diagnostic groupings (mood/anxiety disorders, substance dependence/harmful alcohol use, no selected psychiatric disorder).Results Of the 14,934 respondents age 18–64 years who engaged in at least one type of gambling activity in the previous 12 months, 5.8% fell in the low severity gambling category while 2.9% fell in the moderate/high severity category. Females accounted for 51.7% of the sample. The risk of moderate/high severity gambling was 1.7 times higher in persons with mood or anxiety disorder compared to persons with no selected disorder. For persons with substance dependence or harmful alcohol use, the risk of moderate/high severity gambling was 2.9 times higher. Persons with both mood/anxiety and substance/alcohol disorders were five times more likely to be moderate/high severity gamblers. The odds ratio for females was 0.6 and for those with less than post-secondary education it was 1.52. Differences in age and personal income were not significant.Conclusions Individuals in the community suffering from mood/anxiety disorders and substance dependence/harmful alcohol, and especially those with both, experience a higher risk for gambling problems. The treatment of these comorbidities should be integrated into any problem gambling treatment program.Disclaimer: The data upon which of the analyses contained in this paper derive from surveys conducted by Statistics Canada. The opinions expressed in this paper do not represent the opinions of Statistics Canada.     

农户宅基地使用权流转意愿及影响因素研究——基于武汉市江夏区210户调查问卷分析

以武汉市江夏区为研究区域,通过对江夏区210个农户的实地问卷调查,首先分析了江夏区宅基地使用现状,宅基地使用权流转呈现的特点,进一步应用Logistic回归模型定量的分析农户宅基地使用权流转的影响因素。研究结果表明:户主文化程度、供养系数、非农就业率、距离城镇的距离、家庭宅基地和房屋的价值,这些因素对于农户宅基地使用权流转具有显著性的影响。     

集体林权改革绩效评价:林地利用变化视角

基于林地利用变化视角评价林权改革绩效,并结合问卷调查结果,从林地保护、森林砍伐、林业技术等方面提出了相关的对策建议。结果表明:林改后未成林造林地面积增长迅速,说明林改政策调动了林农造林积极性;有林地面积略有下降与无立木林地有所增加,说明林改后森林砍伐面积呈增长态势,但森林资源质量趋向提高;苗圃地和竹林地面积的增加则反映了林改后林木交易市场更趋活跃及对林产品的需求呈增长态势。