PowerUp!: A Tool for Calculating Minimum Detectable Effect Sizes and Minimum Required Sample Sizes for Experimental and Quasi-Experimental Design Studies

Abstract

This paper and the accompanying tool are intended to complement existing supports for conducting power analysis tools by offering a tool based on the framework of Minimum Detectable Effect Sizes (MDES) formulae that can be used in determining sample size requirements and in estimating minimum detectable effect sizes for a range of individual- and group-random assignment design studies and for common quasi-experimental design studies. The paper and accompanying tool cover computation of minimum detectable effect sizes under the following study designs: individual random assignment designs, hierarchical random assignment designs (2-4 levels), block random assignment designs (2-4 levels), regression discontinuity designs (6 types), and short interrupted time-series designs. In each case, the discussion and accompanying tool consider the key factors associated with statistical power and minimum detectable effect sizes, including the level at which treatment occurs and the statistical models (e.g., fixed effect and random effect) used in the analysis. The tool also includes a module that estimates for one and two level random assignment design studies the minimum sample sizes required in order for studies to attain user-defined minimum detectable effect sizes.     

Item Response Models for Local Dependence Among Multiple Ratings

Ratings given to the same item response may have a stronger correlation than those given to different item responses, especially when raters interact with one another before giving ratings. The rater bundle model was developed to account for such local dependence by forming multiple ratings given to an item response as a bundle and assigning fixed‐effect parameters to describe response patterns in the bundle. Unfortunately, this model becomes difficult to manage when a polytomous item is graded by more than two raters. In this study, by adding random‐effect parameters to the facets model, we propose a class of generalized rater models to account for the local dependence among multiple ratings and intrarater variation in severity. A series of simulations was conducted with the freeware WinBUGS to evaluate parameter recovery of the new models and consequences of ignoring the local dependence or intrarater variation in severity. The results revealed a good parameter recovery when the data‐generating models were fit, and a poor estimation of parameters and test reliability when the local dependence or intrarater variation in severity was ignored. An empirical example is provided.     

不同认知水平的解答编码对数学公式学习的影响研究

图形编码、示意编码和标签编码对公式学习具有不同的影响.高认知水平的图形编码在公式以情景方式呈现时,作业成绩最优;无论是否图形提示,在7天之后的回忆实验中,图形编码的回忆成绩最优,且图形编码对于图形提示极为敏感.     

阅读教学对于不同语言水平者有效性的实证研究

通过教学实践检验阅读教学对于目前分级教学环境下不同语言水平学生的有效性,为今后的大英教学提供实证依据。研究对象为语言水平较高(A1,A2班)和语言水平较低(C1,C2班)的大一新生。其中A1班,C1班为实验班,将ER纳入大学英语课程体系;A2、C2为对照班,沿用传统的以IR为主的教学方法。对照班和实验班均由一名教师担任教学,实验过程为一个学期(约15周),学期结束后,进行测验,运用SPSS13.0分析前后测结果。结果表明,语言水平较高者的实验组比控制组取得了更大进步,达到显著性水平;语言水平较低者的前后测增值,实验组虽高于控制组,但未达到显著性差异。     

Levels of Analysis in Higher Education Research

This article examines the levels of analysis adopted in higher education research, using a database of 567 articles published in 15 leading higher education journals internationally during 2010. Level of analysis is a relatively overlooked issue in this field of research, when compared with methodology, theory and/or topic—to which it is, of course, closely related—but is worthy of more investigation. The article seeks to address the question of whether certain levels of analysis are more or less common for different kinds of research. Eight levels of analysis are recognized, varying from the individual, through the course, department, institution, region, nation and system up to the international. The relationships between level of analysis, journal, theme, methodology and authors' characteristics are considered. It is argued that, given the constraints of available data and intended audiences, while valuable research may be conducted at all levels of analysis, the key issue is choosing an appropriate level for the questions being explored, and the methods and theories being applied.     

The Implications of Contamination for Educational Experiments With Two Levels of Nesting

ABSTRACT

Experimental evaluations that involve the educational system usually involve a hierarchical structure (students are nested within classrooms that are nested within schools, etc.). Concerns about contamination, where research subjects receive certain features of an intervention intended for subjects in a different experimental group, have often led researchers to randomize units at a higher level of the educational hierarchy. Existing work on two-level designs suggests that situations where contamination should lead to randomization at a higher level are likely to be rare. This article extends these results to the case of three-level designs. In order to understand the implications of mathematical results, existing information about the size of intracluster correlation coefficients (ICCs) in educational studies with three levels and about the extent of treatment effect heterogeneity across schools is discussed. Better empirical estimates of ICCs, treatment effect heterogeneity, and plausible contamination values are necessary to make full use of the results in this article. However, it seems likely that situations where contamination should lead to randomization at a higher level in three-level designs are rare.     

军校电工实验分层教学模式的探索实践

针对我校电工与电路基础课程实验教学内容、方法手段、评价方式未能很好地与教学对象的群体差异相适应的问题,在教学过程中引入了分层教学理念,探索分层教学模式的应用实践,主要围绕实施依据、实施策略、实施反馈等情况进行了详细阐述。实践结果证明,分层教学模式是针对差异性教学对象提升教学效果的有效方式,有利于提升教员教学水平和人才培养的质量,值得进一步研究推广。     

Efficacy and safety of rituximab therapy for systemic lupus erythematosus: a systematic review and meta-analysis

Objective: To review the efficacy and safety of rituximab therapy for systemic lupus erythematosus (SLE).Methods: We searched for randomized controlled trails and observational studies that evaluated the effect of rituximab based on the systemic lupus erythematosus disease activity index (SLEDAI), British Isles lupus assessment group index (BILAG), urine protein levels, and the prednisolone dose, and had adequate data to calculate the mean, standard deviation (SD), and 95% confidence intervals, and to systematically review and meta-analyze observational studies with fixed effects model or random effects model. Results: We included 2 randomized controlled studies and 19 observational clinical studies. We summarized the data from the 19 observational studies, analyzed the heterogeneity of the literature, and then used fixed effect model or random effect model for statistical analysis. The SLEDAI, BILAG, and urine protein levels and the prednisolone dosage were decreased after rituximab treatment, and the decreases in the BILAG, urine protein levels, and the prednisolone dose were found to be significant (P<0.05), when compared with baseline level. Rituximab’s adverse effects generally could be controlled with an effective dosing regimen. Conclusions: Although there are still controversies about rituximab’s treatment on SLE, but our study had showed that rituximab had favorable effects on refractory lupus. The long-term efficacy and safety of rituximab require further study.     

Multilevel covariance structure analysis of sibling antisocial behavior

Conventional covariance structure analysis, such as factor analysis, is often applied to data that are obtained in a hierarchical fashion, such as siblings observed within families. Multivariate modeling of such data, however, is most frequently done as if the data were obtained as a simple random sample from a single population. An alternative specification is presented that explicitly models the within‐level and between‐level covariance matrices in familial antisocial behavior. Sibling data from the National Youth Survey, a national probability sample of youth, were used to specify a multilevel covariance structure analysis of sibling antisocial behavior. Results demonstrate homogeneity in antisocial behavior within sibling clusters but heterogeneity across families. These analyses highlight potential pitfalls of ignoring issues of independence and demonstrate how conventional covariance structure software can be easily adapted to handle hierarchical models, providing a large set of new analysis possibilities for multilevel data.     

Can political inequality be reduced in the classroom? Testing the compensation hypothesis and the BFLPE on youth civic competence

This study examines the general question of how classroom characteristics are linked with differences among students in civic competence, which is seen to be an important basis for political inequality. A resource-mobilisation account of youth civic competence is presented, and this is tested using hierarchical linear modelling and International Civic and Citizenship Study 2009 data. The determinants of youth civic competence are explored at the individual, family, and classroom levels, where resource and mobilisation factors at each level are examined. Evidence for classroom effects are tested using Campbell’s compensation hypothesis and insights derived from Marsh’s big-fish-little-pond effect (BFLPE). This case study of the Czech Republic shows limited evidence for an open classroom climate reducing civic competence differences between low- and high-SES students, and no evidence of BFLPE increasing such differences among youths.     

Hierarchical Generalized Linear Models for the Analysis of Judge Ratings

It is known that the Rasch model is a special two-level hierarchical generalized linear model (HGLM). This article demonstrates that the many-faceted Rasch model (MFRM) is also a special case of the two-level HGLM, with a random intercept representing examinee ability on a test, and fixed effects for the test items, judges, and possibly other facets. This perspective suggests useful modeling extensions of the MFRM. For example, in the HGLM framework it is possible to model random effects for items and judges in order to assess their stability across examinees. The MFRM can also be extended so that item difficulty and judge severity are modeled as functions of examinee characteristics (covariates), for the purposes of detecting differential item functioning and differential rater functioning. Practical illustrations of the HGLM are presented through the analysis of simulated and real judge-mediated data sets involving ordinal responses.     

大学物理实验分类培养教学体系的构建

以培养学生实验能力和实验创新能力为核心,将专业类别和实验课程教学体系有机结合,实施专题化、层次化教学模式,构建了大学物理实验分类培养教学体系,实践效果显著,满足了不同层次、不同专业学生对实验能力和创新能力培养的需要.     

Unpacking the relation between morphological awareness and Chinese word reading: Levels of morphological awareness and vocabulary

The nature of the relations among morphological awareness, vocabulary and word reading in Chinese children remains relatively unclear. The present study aimed to distinguish between sublexical morphological awareness, referring to the ability to use the meaning cues of semantic radicals embedded in a compound character, and lexical level morphological awareness, defined as the ability to understand and manipulate single characters (i.e., morphemes) comprising Chinese compound words, on word reading. We also examined the role of vocabulary knowledge on the relation between morphological awareness and word reading at both the sublexical and lexical levels. A group of 172 Chinese second graders were administered measures of sublexical and lexical level morphological awareness, vocabulary knowledge, phonological awareness, orthographic knowledge, nonverbal ability, and word reading. Both sublexical and lexical levels of morphological awareness were moderately correlated with word reading. Vocabulary knowledge appeared to partially mediate the effect of sublexical morphological awareness on word reading, but it fully mediated the effect of lexical level morphological awareness on word reading. These results suggest that sublexical and lexical level morphological awareness play distinct roles in Chinese word reading; vocabulary knowledge is an important factor influencing the relation between morphological awareness and word reading in Chinese.     

国内心理咨询师培训中存在的问题及对策

针对国内心理咨询师培训中存在准入门槛低,专业背景千差万别;偏重理论提升,忽视人格因素;典型的应试教育,讲授为主等问题,建议通过实施分层培养,满足不同水平学员的发展需求;增加个人成长模块,促进心理咨询师的人格完善;突出体验式教学,生成心理咨询师的实践性知识;强化后续培训,保障心理咨询师的可持续发展等策略提高心理咨询师培训的实效性。     

The Impact of Omitting Random Interaction Effects in Cross-Classified Random Effect Modeling

The present study examines bias in parameter estimates and standard error in cross-classified random effect modeling (CCREM) caused by omitting the random interaction effects of the cross-classified factors, focusing on the effect of a sample size within cells and ratio of a small cell. A Monte Carlo simulation study was conducted to compare the correctly specified and the misspecified CCREM. While there was negligible bias in fixed effects, substantial biases were found in the random effects of the misspecified model depending on the number of samples within a cell and the proportion of small cells. However, in the case of the correctly specified model, no bias occurred. The present study suggests considering the random interaction effects when conducting CCREM to avoid overestimation of variance components and to calculate an accurate value of estimation. The implications of this study are to illuminate the conditions of cross-classification ratio and to provide a meaningful reference for applied researchers using CCREM.     

试析艺术作品的构成层次

艺术语言、艺术形象、艺术意蕴构成了艺术作品的三个层次。艺术语言是作品最外部的层面,也是传达内容、塑造形象的重要艺术手段;透过外在的艺术语言层,进而所感受到的是艺术形象层,它是审美主体与审美客体相互交融所创作出来的艺术成果;艺术意蕴则指潜藏于作品深层的人生哲理或精神内涵。三个层次各具独立性,却又相互融合在一起,共同构成一部完美的艺术作品。     

希腊字母不同学习程度的SNARC效应

为考察新的顺序性符号在不同学习程度下的SNARC效应,以30名大学生为被试,以视觉呈现的方式,让被试对17个希腊字母进行学习,学习的程度分为“不熟练”和“熟练”两种。结果发现：在视觉呈现方式下被试学习希腊字母在熟练和不熟练时都产生显著的SNARC效应,而且,前者比后者更显著。     

Levels in Learning

In 1957, Van Hiele published his study on levels in learning mathematics. In this article we present an elaboration of the theory on levels in learning and an illustration of this theory based on empirical results. We distinguish between three levels: The first is the formation of an image out of a range of familiar examples or experiences. Second, on the basis of the image a schema can be built, which includes all kinds of interrelated details. Third, a theory can be developed with basic assumptions, definitions, and logical inferences. Before entering the next level, the learner should be sufficiently experienced on the actual level. It is shown that the theory on levels in learning can be integrated with other learning principles, such as notions from constructivism.     

Dimensions of Socio-economic Status and their Relationship to Mathematics and Science Achievement at Individual and Collective Levels

Applying two-level structural equation modelling techniques, the current study examined the dimensionality of socio-economic status (SES) and its relationship with mathematics and science performance at student and school levels. Data were drawn from population 2 (13-year-olds) of 17 countries in the Third International Mathematics and Science study (TIMSS). A set of items about the ownership of household materials was used to measure the dimensions of SES. For most of the countries, a general economic dimension and a cultural dimension were identified at the student level. The cultural dimension had the greatest impact on students' mathematics and science achievement. At the school level, however, only a general economic dimension was found in most countries. This dimension was interpreted to represent community wealth. It was found to be highly related to school mean maths-science achievement, except for the countries where an additional cultural dimension is identified. This cultural dimension can be interpreted as the community cultural resources and atmosphere, and is strongly related to average school mathematics and science achievement. The current study confirmed that the ownership of a set of household materials can be used as SES indicators in exploring its multifaceted feature at both individual and school levels. A similar model structure is found in different countries by applying these indicators, despite the fact that the content of the set of household possessions is different. The findings show that the latent structure of SES at individual level is different from that at the school level, and that SES dimensions have different effects on mathematics and science achievement at individual and school levels.     

什么因素阻碍了农村学生接受高中教育

2005年末,国家提出农村义务教育经费保障新机制,以促进义务教育资源配置均衡本研究使用三个省区的校级和县级数据,基于准实验研究设计,以小学为例,构建倾向分数配对模型对新机制的影响进行实证研究。研究发现,该政策有利于编小生均公用经费、生均预算内公用经费的县域内支出差异,一定程度上促进了义务教育均衡发展,同时生均支出水平、教师平均工资在县域内还存在一定差异。