Type I error rates from likelihood‐based repeated measures analyses of incomplete longitudinal data

The last observation carried forward (LOCF) approach is commonly utilized to handle missing values in the primary analysis of clinical trials. However, recent evidence suggests that likelihood‐based analyses developed under the missing at random (MAR) framework are sensible alternatives. The objective of this study was to assess the Type I error rates from a likelihood‐based MAR approach – mixed‐model repeated measures (MMRM) – compared with LOCF when estimating treatment contrasts for mean change from baseline to endpoint (Δ). Data emulating neuropsychiatric clinical trials were simulated in a 4 × 4 factorial arrangement of scenarios, using four patterns of mean changes over time and four strategies for deleting data to generate subject dropout via an MAR mechanism. In data with no dropout, estimates of Δ and SE_Δ from MMRM and LOCF were identical. In data with dropout, the Type I error rates (averaged across all scenarios) for MMRM and LOCF were 5.49% and 16.76%, respectively. In 11 of the 16 scenarios, the Type I error rate from MMRM was at least 1.00% closer to the expected rate of 5.00% than the corresponding rate from LOCF. In no scenario did LOCF yield a Type I error rate that was at least 1.00% closer to the expected rate than the corresponding rate from MMRM. The average estimate of SE_Δ from MMRM was greater in data with dropout than in complete data, whereas the average estimate of SE_Δ from LOCF was smaller in data with dropout than in complete data, suggesting that standard errors from MMRM better reflected the uncertainty in the data. The results from this investigation support those from previous studies, which found that MMRM provided reasonable control of Type I error even in the presence of MNAR missingness. No universally best approach to analysis of longitudinal data exists. However, likelihood‐based MAR approaches have been shown to perform well in a variety of situations and are a sensible alternative to the LOCF approach. MNAR methods can be used within a sensitivity analysis framework to test the potential presence and impact of MNAR data, thereby assessing robustness of results from an MAR method. Copyright © 2004 John Wiley & Sons, Ltd.     

图书馆实现知识管理的思考

介绍图书馆知识管理的内容,分析知识管理对图书馆管理核心、业务工作范围、信息技术要求的影响,提出了构建知识团队组织、运用支撑知识管理的信息技术、显性知识的数字化处理、注重智力知识资源开发是图书馆实现知识管理的有效途径。     

试论伪造货币罪的犯罪构成要件

伪造货币罪是最严重的货币犯罪，具体表现为仿照真货币制造假货币的行为。该行为的特点是“无中生有”、“仿真造假”。其仿制的对象既包括人民币，又包括外币，但不包括信用货币。伪造货币罪在主观方面应以“意图流通”为必备条件。根据刑法规定，该罪的犯罪主体仅限于自然人，不包括单位。     

Significant Factors of Aviation Insurance and Risk Management Strategy: An Empirical Study of Taiwanese Airline Carriers

Aviation insurance premiums have become a heavy burden for the airline industry since September 11, 2001. Although the industry must constantly balance its operations between profitability and safety, the reality is that airlines are in the business of making money. Therefore, their ability to reduce cost and manage risk is a key factor for success. Unlike past research, which used subjective judgment methods, this study applied quantitative historical data (1999–2000) and gray relation analysis to identify the primary factors influencing ratemaking for aviation insurance premiums. An empirical study of six airlines in Taiwan was conducted to determine these factors and to analyze the management strategies used to deal with them. Results showed that the loss experience and performance of individual airlines were the key elements associated with aviation insurance premiums paid by each airline. By identifying and understanding the primary factors influencing ratemaking for aviation insurance, airlines will better understand their relative operational strengths and weaknesses, and further help top management identify areas for further improvement. Knowledge of these factors combined with effective risk management strategies, may result in lower premiums and operating costs for airline companies.     

大学生权利保障：权力和权利辨析的视角

当下大学生的权利被广泛关注，但是大学生的权利却往往不能得到很好的保障和维护，其中一个重要原因就是大学生缺乏一个强有力的权力保障。在我国高等教育的现实中，大学生在学校管理中的权力却微乎其微。权利必须用权力来维护和保障。由此，应正视权利和权力的本质区别；在学校管理中赋予大学生合法的地位和身份，给予其参与管理学校的权力；组建大学生自治组织，用相对独立的权力维护其权利，从而加强大学生在学校管理中的权力来使大学生权利得到根本性的保障和维护。     

论破窗理论对高校班级管理的启示

班级管理在大学教育中的作用十分重要。从破窗理论出发．明确了班级环境在班级建设与发展中的重要地位，论述了班级中潜抑力量与压抑力量转化的意义，在此基础上进一步提出，要从加强日常管理、形成良性反馈机制、处理好突发事件三个方面预防“破窗现象”，并针对破窗理论的运用提出了建议。     

论彼得·圣吉的管理哲学

彼得·圣吉是美国著名的管理学家。他的管理哲学从管理理论与管理实践、管理主体与管理客体、管理手段与管理目的、管理组织系统与管理环境之间的关系等四个维度全面揭示了管理科学的发展取向 ,深邃而富有内涵 ,值得我们研究和探讨     

建立高效的高校物流体系

将经济领域的物流引入高校,提出了高校物流体系概念;介绍了高校物流的组成要素及物流目标。为了增加高校在市场环境中的适应性及竞争能力,首先应提高物流系统中的管理水平,从整合、优化、预测的角度制定适应新形势下的物流战略。     

绿色供应链管理动力/压力影响模型实证研究

文章借鉴国外文献及国内环保专家的意见设计问卷进行调研,通过因子分析识别出中国制造企业绿色供应链管理的压力/动力和实践的主要因子.对因子进行相关分析和回归分析,根据数据结合国内外相关情况探讨动力/压力是如何影响绿色供应链管理实践,提出中国制造企业绿色供应链管理的动力/压力影响模型.     

新时期公立高校学生管理的法治化研究

探究公立高校学生管理的法治化，推进高校依法治校，促进高校和谐管理正日益成为高校构建和谐校园的重要方面。从传统高校学生管理存在的问题入手，提出了新时期高校学生的管理应当以构建和谐校园为目标，正确认识高校与学生的法律关系，把握高校学生管理的法治化原则，探究高校学生管理法治化道路。