Missing item imputation for quality-of-life instruments with application to asthma quality-of-life questionnaires

There has been increasing use of quality-of-life (QoL) instruments in drug development. Missing item values often occur in QoL data. A common approach to solve this problem is to impute the missing values before scoring. Several imputation procedures, such as imputing with the most correlated item and imputing with a row/column model or an item response model, have been proposed. We examine these procedures using data from two clinical trials, in which the original asthma quality-of-life questionnaire (AQLQ) and the miniAQLQ were used. We propose two modifications to existing procedures: truncating the imputed values to eliminate outliers and using the proportional odds model as the item response model for imputation. We also propose a novel imputation method based on a semi-parametric beta regression so that the imputed value is always in the correct range and illustrate how this approach can easily be implemented in commonly used statistical software. To compare these approaches, we deleted 5% of item values in the data according to three different missingness mechanisms, imputed them using these approaches and compared the imputed values with the true values. Our comparison showed that the row/column-model-based imputation with truncation generally performed better, whereas our new approach had better performance under a number scenarios.     

Implementing a diversity policy through public incentives: Diversity Plans in companies of the Brussels-Capital Region

ABSTRACT

The development of diversity policies in the private sector is mostly a result of a voluntary engagement of companies. When interested, they decide about the ways and goals of such policies, implications for human resource management and the inclusion of staff with a migration background. This article explores a specific situation in which public authorities offered support and resources to companies in order to develop diversity policies. I present a first analysis of the implementation dynamics of the Brussels Diversity Plan, a policy instrument launched in 2007 by the Government of the city-region of Brussels. Building on the theoretical tools of the political sociology of public policies, I use qualitative material (interviews and administrative documents) to explore implementation processes in three private companies. I show that public authorities can play a decisive role in developing diversity policies in the private sector through incentives rather than constraint. Yet, the room for manoeuver offered to companies leads to important variations regarding how processes unfold and the results achieved.     

集体耕作制时期农村人口增长分析

通过文献参阅,运用现代经济学和社会学相关理论和方法,探索性地分析集体耕作制时期,农地产权残缺、社会的高度封闭性及平均分配主义的影响和中国农村人口的快速增长。改革开放30年来,影响中国农村人口快速增长的诸因素和人口低生育水平反弹的压力基本消除。面对人口长期负惯性增长的新趋势,中国应及时调整生育政策。     

Assessing participants’ perceptions on group-based principles for action in community-based health enhancing physical activity programmes: The APEF tool

In community-based health enhancing physical activity (CBHEPA) programmes, group-based principles for action such as active participation, enjoyment, and fostering group processes are widely advocated. However, not much is known about participants’ perceptions of these principles as there are no assessment tools available. Therefore, this article describes the development of the APEF (Active Participation, Enjoyment, and Fostering group processes) tool and reports on its implementation in a Dutch CBHEPA programme. Indicators for the principles have been identified from literature research, interviews with professionals, and secondary analysis of three group interviews with 11 practitioners. To address the identified indicators, the APEF tool was developed, pretested, and used in 10 focus groups with 76 participants.The APEF tool consists of eight statements about group-based principles for action, on which CBHEPA participants vote, followed by in-depth discussion. The voting procedure engages participants. Spider diagrams visualise participants’ perceptions of group-based principles.The APEF tool addresses the challenge of relating group level outcomes to individual outcomes such as physical activity behaviour. The tool facilitates as well as evaluates group-based principles for action, it stimulates dialogue and is culturally sensitive, but it needs strong facilitating skills to manage group dynamics.     

In Search of the Optimum Harvey Wallbanger Recipe via Mixture Experiment Techniques

A Harvey Wallbanger is an alcoholic drink composed of three ingredients: orange juice, vodka, and Galliano. One of the authors (Sahrmann), a connoisseur of the libation, was perplexed upon discovering that different bartender handbooks listed different recipes for the drink. Determined to shed some light on this irksome problem, he issued invitations for an evening workshop session (party) to former and current attendees of an experimental-design training course taught within his company. A mixture experiment was designed and data collected using the class participants. This article describes the experimental design and the analysis of the data. The results of the experiment indicate that reducing the proportion of vodka produces better-flavored drinks. The results of the experiment were not entirely conclusive, however, so recommendations are made for future experimentation.     

Moment expressions and summary statistics for the complete and truncated weibull distribution

Traditionally, the moments of the Weibull distribution have been calculated using the standard Weibull (Johnson and Kotz, 1970) . This article will expand on that idea and cover the truncated cases for the standard Weibull distributions. Also, the same techniques used for the standard form will be used to derive the moment expressions for the three-parameter complete and truncated Weibull distributions. The summary statistics are then calculated from the moment expressions. Weibull moments involve the gamma and incomplete gamma functions.     

企业财务状况与投资者关系管理--来自 IR 百强上市公司的经验证据

依据“2007年度中国最佳投资者关系管理百强”榜的评选结果,研究了企业财务状况对上市公司投资者关系管理的影响.结果表明,投资者关系管理与企业盈利能力负相关,与股东获利能力、发展能力以及企业现金流量能力正相关.研究还发现,公司规模和流通股比例有利于提升投资者关系管理水平.     

《现代汉语词典》科技术语义项漏略商榷

《现代汉语词典》(2002年增补本)的科技术语存在着义项漏略问题,有的是专科义项漏略,如"干涉"、"权数";有的是语文义项漏略,如"毒瘤"、"腐蚀剂"、"催化剂"。     

非人力资产所有权与企业的边界

产权理论是第一个关于不完全合约和企业合并的正式模型,其核心内涵是说明在不完全合约和潜伏着"敲竹杠"问题的环境中,非人力资产所有权如何影响交易参与人的关系专用性投资。通过考察该理论的基本假设和概念框架发现,它不能对企业边界的决定提供恰当的和充分的解释。企业不仅仅是解决"敲竹杠"问题的机制,合并也不是解决"敲竹杠"问题的惟一途径。     

审美文化中的人文理性和工具理性

科学技术的发展与审美文化的发展之间存在着相互作用的关系 ,这种关系使人文理性与工具理性之间的交流与沟通在当代成为迫切的要求 ;审美文化结合传统的艺术审美与当代的技术审美 ,探索技术进步与人的自由发展的新关系 ,这种积极的探索对人类的生活意义重大