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.     

科学发展观视角下的广西北部湾经济区对外开放新探

广西北部湾经济区对外开放水平仍然比较低是一个不争的事实,广西北部湾经济区要改变这一局面,真正提高广西北部湾经济区对外开放的效能,必须以科学发展观为指导,在广西北部湾经济区的开放战略和定位上进行相应的调整和安排,将经济结构和产业结构的调整有机结合起来,真正处理好对内开放与对外开放的关系、扩大开放程度与加大开发度的关系、扩大开放与维护产业安全的关系、扩大开放中的制度创新与技术创新的关系、扩大开放程度中"引进来"与"走出去"的关系,全面提高开放型经济水平.     

Implied Preference for Seismic Design Level and Earthquake Insurance

Seismic risk can be reduced by implementing newly developed seismic provisions in design codes. Furthermore, financial protection or enhanced utility and happiness for stakeholders could be gained through the purchase of earthquake insurance. If this is not so, there would be no market for such insurance. However, perceived benefit associated with insurance is not universally shared by stakeholders partly due to their diverse risk attitudes. This study investigates the implied seismic design preference with insurance options for decisionmakers of bounded rationality whose preferences could be adequately represented by the cumulative prospect theory (CPT). The investigation is focused on assessing the sensitivity of the implied seismic design preference with insurance options to model parameters of the CPT and to fair and unfair insurance arrangements. Numerical results suggest that human cognitive limitation and risk perception can affect the implied seismic design preference by the CPT significantly. The mandatory purchase of fair insurance will lead the implied seismic design preference to the optimum design level that is dictated by the minimum expected lifecycle cost rule. Unfair insurance decreases the expected gain as well as its associated variability, which is preferred by risk-averse decisionmakers. The obtained results of the implied preference for the combination of the seismic design level and insurance option suggest that property owners, financial institutions, and municipalities can take advantage of affordable insurance to establish successful seismic risk management strategies.     

人大代表对公民意识的影响

民主政治与公民意识关联互动,在这种互动中,精英分子有着重要的影响。在人民代表大会制度中,人大代表理应是民主政治的精英分子,他们的意识和行为对公民意识的影响不容忽视,因此要提高人大代表的素质,强化这种影响。     

广西北部湾经济区打造增长新一极优势依托分析

优势依托理论演进表明,经济的又好又快增长取决于综合优势的发挥,而综合优势的发挥更意味着在发挥比较优势的基础上,一要改进交易效率(如制度创新),二要提高竞争优势(首先是技术创新、其次才是产业升级)。因此,广西北部湾经济区打造经济增长新一极绝不能再走我国沿海发达地区曾经走过的路子,即绝不能再采用那种依赖资源禀赋比较优势的粗放的代工增长模式,只能采用依托于综合优势的新增长模式。     

Time, Self, and the Curiously Abstract Concept of Agency*

The term "agency" is quite slippery and is used differently depending on the epistemological roots and goals of scholars who employ it. Distressingly, the sociological literature on the concept rarely addresses relevant social psychological research. We take a social behaviorist approach to agency by suggesting that individual temporal orientations are underutilized in conceptualizing this core sociological concept. Different temporal foci—the actor's engaged response to situational circumstances—implicate different forms of agency. This article offers a theoretical model involving four analytical types of agency ("existential,""identity,""pragmatic," and "life course") that are often conflated across treatments of the topic. Each mode of agency overlaps with established social psychological literatures, most notably about the self, enabling scholars to anchor overly abstract treatments of agency within established research literatures.     

Gender and the 'New Paradigm' of Health

This article provides a critical review of literature on the relationship between gender and the 'new paradigm' of health. An overview of the feminist critique of health is given, from the Women's Health Movement of the late 1960s and early feminist debates about medicalisation, to more recent discussions about structural inequalities between men and women, eating disorders, and AIDS. I then go on to explore the feminist response to the so-called 'new paradigm' of health (an approach that emphasises health promotion, individual responsibility for health, and body-monitoring). Arguments that health promotion initiatives target women and confirm their position as principal guardians of health within the family are considered, as well as literature on the breast cancer awareness campaign. I then explore the growing body of literature on masculinity and health, and its account of the relationship between gender and current ideas about healthiness. Finally, I offer up some suggestions for the direction a new feminist critique of health might take.     

提高企业家物质激励水平的理论思考

企业家作为社会阶层一特殊群体,必须取得与其业绩相对应的报酬。文章试图从委托-代理理论、人力资本理论、新古典经济增长理论和能力本位制理论等视角分析提高企业家物质激励现有水平的必要性。     

新时期我国零售业发展特点及政策建议

加入WTO以来,伴随我国经济的持续增长、对外开放的不断扩大和居民消费水平的提高,我国零售业在规模、结构、效益、经营和管理水平等方面都上了一个新台阶,但同时也面临来自外资零售企业的竞争压力和行业内现存的发展模式粗放、企业核心竞争力低、规范化程度低、人才短缺等问题,客观上要求必须从财政、税收、技术、人才等方面加快完善零售业发展的政策环境,为零售业的发展创造良好的条件。