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931.
Takahiro Hoshino 《Psychometrika》2007,72(4):535-549
Due to the difficulty in achieving a random assignment, a quasi-experimental or observational study design is frequently used
in the behavioral and social sciences. If a nonrandom assignment depends on the covariates, multiple group structural equation
modeling, that includes the regression function of the dependent variables on the covariates that determine the assignment,
can provide reasonable estimates under the condition of correct specification of the regression function. However, it is usually
difficult to specify the correct regression function because the dimensions of the dependent variables and covariates are
typically large. Therefore, the propensity score adjustment methods have been proposed, since they do not require the specification
of the regression function and have been applied to several applied studies. However, these methods produce biased estimates
if the assignment mechanism is incorrectly specified. In order to make a more robust inference, it would be more useful to
develop an estimation method that integrates the regression approach with the propensity score methodology. In this study
we propose a doubly robust-type estimation method for marginal multiple group structural equation modeling. This method provides a consistent estimator
if either the regression function or the assignment mechanism is correctly specified. A simulation study indicates that the
proposed estimation method is more robust than the existing methods.
This research was partially supported by the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Young Scientists
(B), 187-30406. 相似文献
932.
When there exist omitted effects, measurement error, and/or simultaneity in multilevel models, explanatory variables may be
correlated with random components, and standard estimation methods do not provide consistent estimates of model parameters.
This paper introduces estimators that are consistent under such conditions. By employing generalized method of moments (GMM)
estimation techniques in multilevel modeling, the authors present a series of estimators along a robust to efficient continuum.
This continuum depends on the assumptions that the analyst makes regarding the extent of the correlated effects. It is shown
that the GMM approach provides an overarching framework that encompasses well-known estimators such as fixed and random effects
estimators and also provides more options. These GMM estimators can be expressed as instrumental variable (IV) estimators
which enhances their interpretability. Moreover, by exploiting the hierarchical structure of the data, the current technique
does not require additional variables unlike traditional IV methods. Further, statistical tests are developed to compare the
different estimators. A simulation study examines the finite sample properties of the estimators and tests and confirms the
theoretical order of the estimators with respect to their robustness and efficiency. It further shows that not only are regression
coefficients biased, but variance components may be severely underestimated in the presence of correlated effects. Empirical
standard errors are employed as they are less sensitive to correlated effects when compared to model-based standard errors.
An example using student achievement data shows that GMM estimators can be effectively used in a search for the most efficient
among unbiased estimators.
This research was supported by the National Academy of Education/Spencer Foundation and the National Science Foundation, grant
number SES-0436274. We thank the editor, associate editor, and referees for detailed feedback that helped improve the paper. 相似文献
933.
John T. Mitchell Nathan A. Kimbrel Natalie E. Hundt Amanda R. Cobb Rosemery O. Nelson-Gray Christopher M. Lootens 《欧洲人格杂志》2007,21(7):869-887
Reinforcement Sensitivity Theory (RST) and the Five-Factor Model (FFM) are two prominent personality accounts that have emerged from different backgrounds. Although the two accounts are applied to similar research topics, there is limited empirical work examining the correspondence between them. The current study explored the relationship between RST-based personality traits and the FFM domains and facets in an undergraduate sample (n = 668). Regression analyses indicated that Sensitivity to Punishment (SP) was positively associated with Neuroticism and Agreeableness, and negatively associated with Extraversion, Openness, and Conscientiousness. In contrast, Sensitivity to Reward (SR) was positively associated with Extraversion and Neuroticism, and negatively associated with Agreeableness and Conscientiousness. Exploratory analyses at the facet level specified the relationship between SP, SR, and each domain. A factor analysis was also conducted to explore the higher-order factor structure of RST and the FFM domains. Three factors emerged, which we labelled SP, Stability-Impulsivity, and Sensation Seeking. Taken together, these findings suggest that there is substantial overlap between these two accounts of personality. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
934.
随着医学的进步,在新的医疗形势下,肝移植是对器官移植科医师的巨大挑战,在实际临床工作中,应首先树立正确的器官移植医患关系观,不断提高自己的人文修养和职业素养,进一步完善与肝移植相关的新的知识结构,运用正确的哲学理念和逻辑方式来处理与肝移植相关的临床问题。使肝移植患者得到满意的治疗效果。 相似文献
935.
变性术后患者心理状况的影响因素分析及对策 总被引:1,自引:0,他引:1
变性术后的患者是个特殊的弱势群体,心理问题非常突出,它是生理、个人、家庭、社会等多种因素交互影响的结果;因此,通过社会、家庭及个体的共同努力,帮助其建立良好的个体心理模式,稳定其心理状态,可促进其心理的健康发展,这对于变性手术的成功和帮助变性后患者重新走向社会有重要意义。 相似文献
936.
937.
焦虑和抑郁动物模型的研究方法和策略 总被引:15,自引:2,他引:13
焦虑和抑郁障碍是严重威胁人们健康的精神疾病。焦虑和抑郁动物模型是通过一定的心理社会应激使动物产生明显的焦虑和抑郁情绪,模拟人类焦虑和抑郁障碍,以探讨其细胞、分子和基因水平机制。情绪障碍动物模型通常通过表面效度、结构效度和预测效度进行评价。目前的动物模型虽然存在一定的缺点,但已经为临床和科研提供了巨大帮助。 相似文献
938.
样例学习条件下的因果力估计 总被引:2,自引:1,他引:1
在逐个呈现因果样例的条件下,考察单一因果关系因果力估计的特点,同时检验联想解释,概率对比模型,权重DP模型,效力PC理论和pCI规则。实验让65名大学生被试估计不同化学药物影响动物基因变异的能力。实验结果表明:(1)对产生原因的因果力估计符合权重DP模型;(2)对预防原因的因果力估计较多符合效力PC理论;(3)因果力估计具有复杂多样性,难以用统一的模式加以描述和概括。 相似文献
939.
940.
异同判断加工中整体和局部特征的作用 总被引:1,自引:0,他引:1
采用三种整体局部特征(关系-属性,全局-局部,抽象-具体)图形,要求3组大学生被试完成异同判断任务,以考察异同判断加工中整体和局部特征的作用,探讨异同比较的加工机制。三个实验的结果表明:⑴三种整体特征均可加速同反应,因而不支持同判断加工是整体匹配的观点;⑵存在快同效应,但并不支持同判断的快速加工器对整个刺激加工完成后慢速比较器才开始工作的观点;⑶异反应时随差异特征的增多而减小,从而进一步支持异判断是分析加工、自终止的观点;⑷异反应时随差异特征从上至下、从整体到局部而增加,意味着异判断加工的顺序可能是自上而下、从整体到局部。上述结果支持研究假设:同判断的快速加工器先加工整体特征,然后再和异判断的慢速比较器一起开始加工局部特征。 相似文献