The Relationship Between Volunteers' Work Behaviors and Background and Preparation Variables

Increasingly, a large number of individuals provide volunteer services. Demographic information known about these individuals is also increasing. Although recent efforts have attempted to examine more closely the relationships between demographic and background variables and subsequent volunteer motivation and retention, few have studied how these variables impact actual work performed by volunteers. This study provides a model for how volunteers' demographic and background variables may be related to volunteers' perceptions of the frequency and importance of their work behaviors. Although it is possible that motivation also may be related to work behaviors, this study provides information ultimately leading to a more complete picture of the potential impact of demographic and background variables on work behaviors.     

情绪代理变量对投资者决策的影响

情绪代理变量是指影响投资者对市场判断的非经济变量,主要包括天气、人体生物钟、月运周期、信念、社会事件、资本形象等。与蝴蝶效应类似,其影响在现实中往往被忽略了,但研究表明它们却会使股票市场出现巨大的波动。文章总结了两类情绪代理变量（“错误归因”情绪变量和“启发式”情绪变量）对投资者决策产生影响的研究,这些研究结果可以使投资者从认识自己的情绪中获益,也可为我国决策层和监管层制定出合理的政策提供依据     

What Carries a Mediation Process? Configural Analysis of Mediation

Mediation is a process that links a predictor and a criterion via a mediator variable. Mediation can be full or partial. This well-established definition operates at the level of variables even if they are categorical. In this article, two new approaches to the analysis of mediation are proposed. Both of these approaches focus on the analysis of categorical variables. The first involves mediation analysis at the level of configurations instead of variables. Thus, mediation can be incorporated into the arsenal of methods of analysis for person-oriented research. Second, it is proposed that Configural Frequency Analysis (CFA) can be used for both exploration and confirmation of mediation relationships among categorical variables. The implications of using CFA are first that mediation hypotheses can be tested at the level of individual configurations instead of variables. Second, this approach leaves the door open for different types of mediation processes to exist within the same set. Using a data example, it is illustrated that aggregate-level analysis can overlook mediation processes that operate at the level of individual configurations.     

企业员工人口学变量、工作特征与主观幸福感的关系：工作压力的作用

本研究通过对北京、上海、南京、成都、长沙及广州266名企业员工有效样本的测查,考察了员工幸福感在人口学变量和工作特征变量上的差异,探讨了工作压力对幸福感的影响机制,发现不同年龄、学历、企业所有制、行业和工作岗位的员工的幸福感水平差异显著,人口学变量和工作特征对幸福感有交互作用。回归分析发现,工作压力、学历和工作类别变量分别直接影响幸福感,年龄和学历还通过工作压力间接影响幸福感。     

Ready or not? Stages of change as predictors of brief group therapy outcome in bulimia nervosa

Although group therapy is often recommended for the treatment of bulimia nervosa, relatively little is known about predictors of short-term outcome. This pilot study examined whether a standardized measure of readiness for change might be related to changes in binge frequency. Sixteen bulimic patients participated in short-term cognitive behavioral group therapy for twelve weeks. Each patient completed the Change Assessment Scale prior to treatment, along with a battery of symptom measures which were readministered at the conclusion of therapy. Bulimic patients with positive outcome in binge frequency were at a higher stage of readiness for change at pretreatment than were patients with negative outcome. Results indicated that there may be methods of determining who would be most likely to benefit from cognitive behavioral group therapy, and tentatively suggest that interventions may be more successful when readiness for change is taken into consideration.     

Items bundles

An item bundle is a small group of multiple choice items that share a common reading passage or graph, or a small group of matching items that share distractors. Item bundles are easily identified by paging through a copy of a test. Bundled items may violate the latent conditional independence assumption of unidimensional item response theory (IRT), but such a violation would not typically suggest the existence of a new fundamental human ability to read one specific reading passage or to interpret one specific graph. It is important, therefore, to have theoretical concepts and empirical checks that distinguish between, on the one hand, anticipated violations of latent conditional independence within item bundles, and, on the other hand, violations that cannot be attributed to idiosyncratic features of test format and instead suggest departures from unidimensionalty. To this end, two theorems on unidimensional IRT are extended to describe observable item response distributions when there is conditional independencebetween but not necessarilywithin item bundles.The author is grateful to Ivo Molenaar and the referees for many helpful suggestions, and to D. Thayer for assistance with computing.     

A generalized method of image analysis from an intercorrelation matrix which may be singular

Following the works of Guttman (1953) and Kaiser (1976), we show that the image and anti-image covariance matrices can be derived from a singular correlation matrix, by making use of the orthogonal projector and a weaker generalized inverse matrix.     

Maximum likelihood estimation of multivariate polyserial and polychoric correlation coefficients

The method of finding the maximum likelihood estimates of the parameters in a multivariate normal model with some of the component variables observable only in polytomous form is developed. The main stratagem used is a reparameterization which converts the corresponding log likelihood function to an easily handled one. The maximum likelihood estimates are found by a Fletcher-Powell algorithm, and their standard error estimates are obtained from the information matrix. When the dimension of the random vector observable only in polytomous form is large, obtaining the maximum likelihood estimates is computationally rather labor expensive. Therefore, a more efficient method, the partition maximum likelihood method, is proposed. These estimation methods are demonstrated by real and simulated data, and are compared by means of a simulation study.     

The relationship between external variables and common factors

A theorem is presented which gives the range of possible correlations between a common factor and an external variable (i.e., a variable not included in the test battery factor analyzed). Analogous expressions for component (and regression component) theory are also derived. Some situations involving external correlations are then discussed which dramatize the theoretical differences between components and common factors.Support by the National Research Council of Canada (NRC Grant No. A4640) and the University of British Columbia (UBC Humanities and Social Sciences Grant 26-9718) is gratefully acknowledged.This paper is based in part on the author's Ph.D. dissertation. I am particularly grateful to my dissertation advisor, Dr. Peter H. Schönemann. Thanks also to the editor and the anonymous reviewers, who contributed many helpful comments and suggestions.