Bayesian networks for imputation

Summary.  Bayesian networks are particularly useful for dealing with high dimensional statistical problems. They allow a reduction in the complexity of the phenomenon under study by representing joint relationships between a set of variables through conditional relationships between subsets of these variables. Following Thibaudeau and Winkler we use Bayesian networks for imputing missing values. This method is introduced to deal with the problem of the consistency of imputed values: preservation of statistical relationships between variables ( statistical consistency ) and preservation of logical constraints in data ( logical consistency ). We perform some experiments on a subset of anonymous individual records from the 1991 UK population census.     

The effect of sociodemographic (mis)match between interviewers and respondents on unit and item nonresponse in Belgium

Interviewer characteristics affect nonresponse and measurement errors in face-to-face surveys. Some studies have shown that mismatched sociodemographic characteristics – for example gender – affect people's behavior when interacting with an interviewer at the door and during the survey interview, resulting in more nonresponse. We investigate the effect of sociodemographic (mis)matching on nonresponse in two successive rounds of the European Social Survey in Belgium. As such, we replicate the analyses of the effect of (mis)matching gender and age on unit nonresponse on the one hand, and of gender, age and education level (mis)matching on item nonresponse on the other hand. Recurring effects of sociodemographic (mis)match are found for both unit and item nonresponse.     

基于SWOT分析的喇叭河森林公园旅游产品策划

基于SWOT分析,喇叭河森林公园既有区位、资源等方面的旅游开发优势,又有生态环境脆弱、资金投入不足、市场开拓不足等方面劣势;既有发展机遇,又面临多方面的挑战.因此,喇叭河森林公园旅游产品策划就应基于锥形的旅游产品结构体系,以"市场导向,资源依托"为策划原则,引进品牌战略,构建多样的项目集群,并实行多元化的经营模式,以吸引更多的游客.     

项目法施工成本辅助管理系统的开发研究

以项目法施工为基础,结合公路工程施工的实际情况,对项目法施工成本辅助管理系统进行了研究开发,通过规范化、标准化的数据录入和系统化的分析处理,将资源消耗管理、成本管理和企业效益评价等工程项目管理中的关键环节联成一个有机的管理系统,如实反映企业的管理水平,实现了工程项目施工成本的动态化和智能化管理。     

Evaluating Item Discrimination Power of WHOQOL-BREF from an Item Response Model Perspectives

Quality of life (QOL) has become an important component of health. By using the methodology of psychometric theory, we examine the item properties of the WHOQOL-BRIEF. Samejima’s graded response model with natural metrics of the logistic response function was fitted. The results showed items with negative natures were less discriminating. Items written in a specific way were more suitable to assess certain subgroups. The national items showed variation in discriminatory power. Questions measuring objective and specific issues performed worse than items assessing general aspects of the QOL.     

Multilevel modelling of refusal and non-contact in household surveys: evidence from six UK Government surveys

Summary.  We analyse household unit non-response in six major UK Government surveys by using a multilevel multinomial modelling approach. The models are guided by current conceptual frameworks and theories of survey participation. One key feature of the analysis is the investigation of the extent to which effects of household characteristics are survey specific. The analysis is based on the 2001 UK Census Link Study, which is a unique source of data containing an unusually rich set of auxiliary variables. The study contains the response outcome of six surveys, linked to census data and interviewer observations for both respondents and non-respondents.     

Obstacles to involving children and young people in foster care research

ABSTRACT Despite increasing recognition of the importance of including the perspectives of children and young people in care in alternative care research, in practice this is not always a straightforward matter. This paper describes the recruitment of disruptive young people in care under the jurisdiction of the South Australian statutory authority to three studies on placement instability. Non‐response rates of 72.5% and 82% are reported. A large number of subjects were excluded because agency social workers did not cooperate with the project, and more subjects were excluded for reasons which suggest high levels of distress in this population. The dilemma of providing a voice to distressed subjects when distressed subjects are excluded from research is discussed, and the appointment of an independent representative for children in care to review research proposals and to negotiate research access to children is proposed.     

本科选项式体育教学的实践与探索

通过对广东培正学院自建院以来体育教学工作的分析,该文阐述并论证当前开展本科选项式体育教学模式的可行性,分析了本科体育教学存在的问题并提出解决办法,为学院本科体育教学的发展提供依据。     

Interval estimation for log-linear models with one variable subject to non-ignorable non-response

Summary.  Log-linear models for multiway contingency tables where one variable is subject to non-ignorable non-response will often yield boundary solutions, with the probability of non-respondents being classified in some cells of the table estimated as 0. The paper considers the effect of this non-standard behaviour on two methods of interval estimation based on the distribution of the maximum likelihood estimator. The first method relies on the estimator being approximately normally distributed with variance equal to the inverse of the information matrix. It is shown that the information matrix is singular for boundary solutions, but intervals can be calculated after a simple transformation. For the second method, based on the bootstrap, asymptotic results suggest that the coverage properties may be poor for boundary solutions. Both methods are compared with profile likelihood intervals in a simulation study based on data from the British General Election Panel Study. The results of this study indicate that all three methods perform poorly for a parameter of the non-response model, whereas they all perform well for a parameter of the margin model, irrespective of whether or not there is a boundary solution.