Practical procedures to deal with common support problems in matching estimation

This paper assesses the performance of common estimators adjusting for differences in covariates, such as matching and regression, when faced with the so-called common support problems. It also shows how different procedures suggested in the literature affect the properties of such estimators. Based on an empirical Monte Carlo simulation design, a lack of common support is found to increase the root-mean-squared error of all investigated parametric and semiparametric estimators. Dropping observations that are off support usually improves their performance, although the magnitude of the improvement depends on the particular method used.     

社会资本与身心健康--概念辨析基础上的关系再检验

社会资本与健康研究领域存在核心概念界定不清与理论解释欠缺两大不足。文章在社会网络的视角下对社会资本、社会凝聚和社会支持三个相互杂糅的概念进行辨析区分，并在此基础上以调查数据实证检验了社会资本对身心健康的作用效果与影响机制。结果显示，在控制社会凝聚和社会支持作用的条件下，社会资本依然对自评健康和心理健康存在显著的独立影响，但其对两种健康在影响因素和影响方向上呈现一些差异。其中，网络规模和网络顶端对自评健康和心理健康都具有显著的正向作用，而心理健康同时还受到网络差异的负向影响。从这个角度而言，社会资本对个体身心健康的影响并不必然是积极正向的。     

The Common Assessment Framework form 9 years on: a creative process

Legislation within England states that local authorities should provide services for all those families in need. However, research has identified that regardless of the introduction of strategies to identify need and enhance family support, ongoing barriers to services adhere. Taking a social constructionist approach, this study explored professionals' experiences of the use of the Common Assessment Framework form. Data were collected in four different local authorities in two phases. Forty‐one professionals from a variety of agencies took part in semi‐structured interviews. Data were analyzed thematically. Findings demonstrate that the professionals experienced difficulties in working through the Common Assessment Framework process, for example, in completing the form and engaging families. This situation led to the more experienced and knowledgeable professionals utilising creative ways to successfully navigate the ‘referral process’. Such creative working practices included the terminology used to complete the form and how the process was ‘sold’ to parents, so that they could be in a better position to engage parents and complete the Common Assessment Framework form. Because of this, more experienced professionals seem to be able to accelerate the referral process in order to access much needed support services for children and young people.     

The bumpy road to ‘becoming’: capturing the stories that teenage mothers told about their journey into motherhood

Understanding the experience of women who become mothers during their teenage years is central to ensuring that the support that is offered is appropriate to meet their needs. This paper reports on a small part of a larger ethnographic study that captured the lived experience of young mothers who were between the ages of 16 and 19 years that potentially typifies and illuminates the experiences of young women who become mothers in their teenage years. By collecting data from narrative interviews as well as participant and non‐participant observations over an extended period of time it was possible to identify how the young women experienced a range of difficulties as they made their transition into motherhood. Drawing on the findings, this paper argues that this transition for teenage mothers can be significantly different from the experience of older mothers, and it identifies the importance of appropriate support to mediate the challenges that they face. Understanding the young women's journey to ‘becoming’ is critical when planning services because if their experience of support is negative, it can lead to increased levels of maternal stress and reluctance to engage with support services.     

Testing the validity of social capital measures in the study of information and communication technologies

Social capital has been considered a cause and consequence of various uses of new information and communication technologies (ICTs). However, there is a growing divergence between how social capital is commonly measured in the study of ICTs and how it is measured in other fields. This departure raises questions about the validity of some of the most widely cited studies of social capital and ICTs. We compare the Internet Social Capital Scales (ISCS) developed by Williams [2006. On and off the ’net: scales for social capital in an online era. Journal of Computer-Mediated Communication, 11(2), 593–628. doi: 10.1111/j.1083-6101.2006.00029.x] – a series of psychometric scales commonly used to measure ‘social capital’ – to established, structural measures of social capital: name, position, and resource generators. Based on a survey of 880 undergraduate students (the population to which the ISCS has been most frequently administered), we find that, unlike structural measures, the ISCS does not distinguish between the distinct constructs of bonding and bridging social capital. The ISCS does not have convergent validity with structural measures of bonding or bridging social capital; it does not measure the same concept as structural measures. The ISCS conflates social capital with the related constructs of social support and attachment. The ISCS does not measure perceived or actual social capital. These findings raise concerns about the interpretations of existing studies of ‘social capital’ and ICTs that are based on the ISCS. Given the absence of measurement validity, we urge those studying social capital to abandon the ISCS in favor of alternative approaches.     

A high breakdown,high efficiency and bounded influence modified GM estimator based on support vector regression

Regression analysis aims to estimate the approximate relationship between the response variable and the explanatory variables. This can be done using classical methods such as ordinary least squares. Unfortunately, these methods are very sensitive to anomalous points, often called outliers, in the data set. The main contribution of this article is to propose a new version of the Generalized M-estimator that provides good resistance against vertical outliers and bad leverage points. The advantage of this method over the existing methods is that it does not minimize the weight of the good leverage points, and this increases the efficiency of this estimator. To achieve this goal, the fixed parameters support vector regression technique is used to identify and minimize the weight of outliers and bad leverage points. The effectiveness of the proposed estimator is investigated using real and simulated data sets.     

基于支持向量机的管理信息系统故障识别模型研究

管理信息系统故障影响着企业信息工程的开展。及时识别故障,能够为企业争取更多时间处理故障。因此,管理信息系统故障识别有着重要的研究意义和实践意义。基于支持向量机,构建管理信息系统故障识别模型,通过把样本应用于该模型,结果表明该模型具有较好的准确性,能有效识别管理信息系统故障。     

The Romance of Surrogacy1

This article seeks to demonstrate and analyze the cultural and emotional work surrogate mothers collectively engage in on the largest surrogacy support website, http://www.surromomsonline.com . Surrogate mothers’ online stories and discussions frame contract surrogacy as a “labor of love.” Women often describe their surrogacy as a “journey” of shared love; they hope for a lasting relationship with the couple they carry for. This article explores how the language of love, learned and internalized through online communication with other surrogates, creates both a cultural conceptualization of surrogacy and a ground for action. Love and altruistic giving are consistent with close interpersonal rather than market relationships; surrogates hope for a long‐term friendship with their couple. Surrogacy journeys, however, not infrequently end in disappointment; surrogates feel betrayed when couples cut ties. As a result of collective learning, surrogates’ discussions increasingly articulate the position that love, even when unreciprocated, can lead to repeated giving; love is noble and ennobling. Surrogates find appreciation and support in their online surrogacy community where they agree that giving life is a moral good. This stance has contributed to a renewed enthusiasm to bear children for others.     

Effects of Network Approval on Accounts of Commitment Trajectories in Intraracial and Interracial Relationships

The current study used dyadic data to investigate the impact of relationship type and social support on the retrospective accounts of commitment trajectories of romantic relationships. Past research suggests that social support is a positive contributor to relationship stability and commitment, which may be especially true for partners in interracial relationships who face broader societal opposition than intraracial couples. Using multilevel modeling, we investigated the effects of sex, relationship type, and social support on reports of commitment. Results showed differences in trajectories of commitment based on couple type (interracial vs. intraracial) for both men and women. Social support was found to have an especially strong impact for women in interracial relationships compared with women in intraracial relationships, but there was no differential impact among men.     

Impact of an Overt Response System on Staff Performance and Maintenance of Computer-Based Instruction

Interactive Computer Based Instruction (CBI) systems involve teaching strategies to facilitate greater response opportunities during training in an effort to improve learner performance. The current study investigated the effect of online staff training videos with and without overt response requirements on posttest and maintenance test scores across six block-randomized instructional modules for four employees of a university located in the southeastern region of the United States. The overt response consisted of multiple-choice questions administered throughout select teaching modules using an alternating treatment design. Findings suggest that learning occurred as a result of the CBI training; however, the effectiveness of the overt response system varied across individuals, with no discernible differentiation between learning gains associated with response requirements. Other areas of research for expanding the efficacy of CBI and overt response systems are highlighted.