Some practical issues in the evaluation of heterogeneous labour market programmes by matching methods

Summary.  Recently several studies have analysed active labour market policies by using a recently proposed matching estimator for multiple programmes. Since there is only very limited practical experience with this estimator, this paper checks its sensitivity with respect to issues that are of practical importance in this kind of evaluation study. The estimator turns out to be fairly robust to several features that concern its implementation. Furthermore, the paper demonstrates that the matching approach per se is no panacea for solving all the problems of evaluation studies, but that its success depends critically on the information that is available in the data. Finally, a comparison with a bootstrap distribution provides some justification for using a simplified approximation of the distribution of the estimator that ignores its sequential nature.     

Covariates and Random Effects in a Gamma Process Model with Application to Degradation and Failure

The gamma process is a natural model for degradation processes in which deterioration is supposed to take place gradually over time in a sequence of tiny increments. When units or individuals are observed over time it is often apparent that they degrade at different rates, even though no differences in treatment or environment are present. Thus, in applying gamma-process models to such data, it is necessary to allow for such unexplained differences. In the present paper this is accomplished by constructing a tractable gamma-process model incorporating a random effect. The model is fitted to some data on crack growth and corresponding goodness-of-fit tests are carried out. Prediction calculations for failure times defined in terms of degradation level passages are developed and illustrated.     

“以学生为中心的主题教学模式”实验研究

通过“以学生为中心的主题教学模式”教改实验测试成绩数据和一系列调查结果的比较分析 ,说明了教学改革对于大学英语课堂教学的效果和学生学习能力的培养有着十分重要的作用     

Covariate Order Tests for Covariate Effect

A new approach for constructing tests for association between a random right censored life time variable and a covariate is proposed. The basic idea is to first arrange the observations in increasing order of the covariate and then base the test on a certain point process defined by the observation times. Tests constructed by this approach are robust against outliers in the covariate values or misspecification of the covariate scale since they only use the ordering of the covariate. Of particular interest is a test based on the Anderson-Darling statistic. This test has good power properties both against monotonic and nonmonotonic dependencies between the covariate and the life time variable.     

技术路径与中国经济增长

中国在改革开放进程中所采取的积极的产业政策拓展了与发达国家或地区的贸易关系,加快了外资引进的步伐。对外贸易和外资引进产生了技术的"外溢"和"干中学"效应,提高了市场的竞争程度,也促使国内企业积极去改进原有技术和开发新技术。这三个技术进步路径共同推动了企业技术的进步,促进了中国经济的增长。     

国外关于社区对儿童和青少年影响的研究

国外关于社区 (neighborhood)对儿童和青少年影响的研究已有多年的历史并取得了不少成果。社区对儿童和青少年的影响效应一般从入学准备情况与学业成绩、行为和情绪问题 (包括外化的和内化的 )、性行为与生育等三个方面来研究考察。社区的结构维度大致可划分收入 /社会经济地位 (可划分为高、中、低三类 ) ,种族混杂程度 ,居民搬迁率等三个。社区对儿童和青少年的影响机制一般从机构资源、亲子关系和组织度三个角度来探讨     

Translating cross-lagged effects into incidence rates and risk ratios: The case of psychosocial safety climate and depression

Longitudinal studies are the gold standard of empirical work and stress research whenever experiments are not plausible. Frequently, scales are used to assess risk factors and their consequences, and cross-lagged effects are estimated to determine possible risks. Methods to translate cross-lagged effects into risk ratios to facilitate risk assessment do not yet exist, which creates a divide between psychological and epidemiological work stress research. The aim of the present paper is to demonstrate how cross-lagged effects can be used to assess the risk ratio of different levels of psychosocial safety climate (PSC) in organisations, an important psychosocial risk for the development of depression. We used available longitudinal evidence from the Australian Workplace Barometer (N?=?1905) to estimate cross-lagged effects of PSC on depression. We applied continuous time modelling to obtain time-scalable cross effects. These were further investigated in a 4-year Monte Carlo simulation, which translated them into 4-year incident rates. Incident rates were determined by relying on clinically relevant 2-year periods of depression. We suggest a critical value of PSC?=?26 (corresponding to ?1.4 SD), which is indicative of more than 100% increased incidents of persistent depressive disorder in 4-year periods compared to average levels of PSC across 4 years.     

民族旅游社区参与的“工分制”

以贵州省雷山县上郎德村为个案。在田野调查的基础上,对上郎德村以＂工分制＂为基础,以集体分配为形式的社区参与旅游模式作了概括的介绍,探讨了＂工分制＂旅游参与模式对上郎德苗族社区经济的积极影响以及对该社区传统文化的正效应,探索了这一模式在构建民族旅游发展模式的可能性。     

论远程教育中多媒体教学资源的应用效果

分析和评价了我国现代远程教育多媒体教学资源的现状和应用效果,针对多媒体教学资源中存在的问题,提出以学生为中心的理念,对多媒体教学资源进行开发设计;用开放性原则来进一步完善多媒体教学资源的建设;从最优化组合的要求对现有的多媒体教学资源进行整合。     

Neighborhood Structure,Social Organization,and Number of Short‐Term Sexual Partnerships

We examine the relationship between neighborhood structural characteristics, social organization, and the sexual partnering practices of adults. Analyses of 1990 census and 1995–1997 survey‐based data on Chicago neighborhoods and adult sexual activity reveal for men a number of neighborhood influences on sexual partnering practices. First, residential stability is negatively associated with having a short‐term sexual partner in the last year. Second, neighborhood social ties are positively associated with short‐term sexual partnering in neighborhoods with low levels of collective efficacy—the combination of cohesion and shared expectations for beneficial action among neighbors—but this effect is substantially reduced as collective efficacy increases. Moreover, neighborhood collective efficacy and social ties mediate the effect of residential stability on sexual partnering practices. Neighborhood characteristics were not associated with short‐term sexual partnering for women.