首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 46 毫秒
1.
Social scientists are frequently interested in identifying latent subgroups within the population, based on a set of observed variables. One of the more common tools for this purpose is latent class analysis (LCA), which models a scenario involving k finite and mutually exclusive classes within the population. An alternative approach to this problem is presented by the grade of membership (GoM) model, in which individuals are assumed to have partial membership in multiple population subgroups. In this respect, it differs from the hard groupings associated with LCA. The current Monte Carlo simulation study extended on prior work on the GoM by investigating its ability to recover underlying subgroups in the population for a variety of sample sizes, latent group size ratios, and differing group response profiles. In addition, this study compared the performance of GoM with that of LCA. Results demonstrated that when the underlying process conforms to the GoM model form, the GoM approach yielded more accurate classification results than did LCA. In addition, it was found that the GoM modeling paradigm yielded accurate results for samples as small as 200, even when latent subgroups were very unequal in size. Implications for practice were discussed.  相似文献   

2.
Multilevel modeling (MLM) is a popular way of assessing mediation effects with clustered data. Two important limitations of this approach have been identified in prior research and a theoretical rationale has been provided for why multilevel structural equation modeling (MSEM) should be preferred. However, to date, no empirical evidence of MSEM's advantages relative to MLM approaches for multilevel mediation analysis has been provided. Nor has it been demonstrated that MSEM performs adequately for mediation analysis in an absolute sense. This study addresses these gaps and finds that the MSEM method outperforms 2 MLM-based techniques in 2-level models in terms of bias and confidence interval coverage while displaying adequate efficiency, convergence rates, and power under a variety of conditions. Simulation results support prior theoretical work regarding the advantages of MSEM over MLM for mediation in clustered data.  相似文献   

3.
基于模型的预测控制器设计最重要的一步是设计一个尽可能精确和在大范围操作条件下有效的模型。煮糖过程是一个具有严重的非线性和不稳定性过程,过程的主要非线性表现在晶体生长率。这篇论文用两种方法来描述晶体生长率模型的设计,第一种方法是传统的方法,它是通过采用非线性规划最优化方法(NLP)决定晶体生长率经验公式的参数;第二种方法是一种新颖的建模策略,它把晶体生长率作为非线性逼近器的人工神经网络(ANN)与由蔗糖晶体质量平衡所表述的先前既定的知识相结合。最初结果显示第一种类型的模型能够较好地执行局部匹配,而第二种具有更大的灵活性。  相似文献   

4.
Exploratory structural equation modeling (ESEM) is an approach for analysis of latent variables using exploratory factor analysis to evaluate the measurement model. This study compared ESEM with two dominant approaches for multiple regression with latent variables, structural equation modeling (SEM) and manifest regression analysis (MRA). Main findings included: (1) ESEM in general provided the least biased estimation of the regression coefficients; SEM was more biased than MRA given large cross-factor loadings. (2) MRA produced the most precise estimation, followed by ESEM and then SEM. (3) SEM was the least powerful in the significance tests; statistical power was lower for ESEM than MRA with relatively small target-factor loadings, but higher for ESEM than MRA with relatively large target-factor loadings. (4) ESEM showed difficulties in convergence and occasionally created an inflated type I error rate under some conditions. ESEM is recommended when non-ignorable cross-factor loadings exist.  相似文献   

5.
This simulation study focused on the power for detecting group differences in linear growth trajectory parameters within the framework of structural equation modeling (SEM) and compared the latent growth modeling (LGM) approach to the more traditional repeated-measures analysis of variance (ANOVA) approach. Several patterns of group differences in linear growth trajectories were considered. SEM growth modeling consistently showed higher statistical power for detecting group differences in the linear growth slope than repeated-measures ANOVA. For small group differences in the growth trajectories, large sample size (e.g., N > 500) would be required for adequate statistical power. For medium or large group differences, moderate or small sample size would be sufficient for adequate power. Some future research directions are discussed.  相似文献   

6.
We examined the stability of responses to a multi‐item self‐esteem scale collected on five occasions over an 8‐year period. A wide variety of approaches were critically examined that considered the stability of means, individual differences (i.e., test‐retest correlations), and factor structures using traditional approaches (e.g., ANOVA and correlations) and structural equation models. Structural equation models based on multiple indicators provided a unified analytic approach for evaluating different aspects of stability and offered important advantages over traditional approaches. We describe a hierarchy of invariances and the nature of interpretations that are justified by different patterns of factor structure invariance associated with each level. We conclude that the assumptions underlying the typical repeated‐measures ANOVA approach to testing mean differences in longitudinal data are far more restrictive, less easily tested, and less likely to be met than those in the structural equation modeling approach advocated here, and that the use of ANOVA for this purpose requires a huge leap of faith that can rarely be justified on logical or empirical grounds.  相似文献   

7.
The authors investigated 2 issues concerning the power of latent growth modeling (LGM) in detecting linear growth: the effect of the number of repeated measurements on LGM's power in detecting linear growth and the comparison between LGM and some other approaches in terms of power for detecting linear growth. A Monte Carlo simulation design was used, with 3 crossed factors (growth magnitude, number of repeated measurements, and sample size) and 1,000 replications within each cell condition. The major findings were as follows: For 3 repeated measurements, a substantial proportion of samples failed to converge in structural equation modeling; the number of repeated measurements did not show any effect on the statistical power of LGM in detecting linear growth; and the LGM approach outperformed both the dependent t test and repeated-measures analysis of variance (ANOVA) in terms of statistical power for detecting growth under the conditions of small growth magnitude and small to moderate sample size conditions. The multivariate repeated-measures ANOVA approach consistently underperformed the other tests.  相似文献   

8.
There is consensus in the statistical literature that severe departures from its assumptions invalidate the use of regression modeling for purposes of inference. The assumptions of regression modeling are usually evaluated subjectively through visual, graphic displays in a residual analysis but such an approach, taken alone, may be insufficient for assessing the appropriateness of the fitted model. Here, an easy‐to‐use test of the assumption of equal variance (i.e., homoscedasticity) as well as model specification is provided. Given the importance of the equal‐variance assumption (i.e., if uncorrected, severe violations preclude the use of statistical inference and moderate violations result in a loss of statistical power) and given the fact that, if uncorrected, a misspecified or underspecified model could invalidate an entire study, the test developed by Halbert White in 1980 is recommended for supplementing a graphic residual analysis when teaching regression modeling to business students at both the undergraduate and graduate levels. Using this confirmatory approach to supplement a traditional residual analysis has value because students often find that graphic displays are too subjective for determining what constitutes severe from moderate departures from the equal variance assumption or for assessing patterns in plots that might indicate model misspecification or underspecification.  相似文献   

9.
Applications of growth mixture modeling have become widespread in the fields of medicine, public health, and the social sciences for modeling linear and nonlinear patterns of change in longitudinal data with presumed heterogeneity with respect to latent group membership. However, in contrast to linear approaches, there has been relatively less focus on methods for modeling nonlinear change. We introduce a nonlinear mixture modeling approach for estimating change trajectories that rely on the use of fractional polynomials within a growth mixture modeling framework. Fractional polynomials allow for more parsimonious and flexible models in comparison to conventional polynomial models. The procedures are illustrated through the use of math ability scores obtained from 499 children over a period of 3 years, with 4 measurement occasions. Techniques for identifying the best empirically derived growth mixture model solution are also described and illustrated by way of substantive example and a simulation.  相似文献   

10.
This study introduces three growth modeling techniques: latent growth modeling (LGM), hierarchical linear modeling (HLM), and longitudinal profile analysis via multidimensional scaling (LPAMS). It compares the multilevel growth parameter estimates and potential predictor effects obtained using LGM, HLM, and LPAMS. The purpose of this multilevel growth analysis is to alert applied researchers to selected analytical issues that are required for consideration in decisions to apply one of these three approaches to longitudinal academic achievement studies. The results indicated that there were no significant distinctions on either mean growth parameter estimates or on the effects of potential predictors to growth factors at both the student and school levels. However, the study also produced equivocal findings on the statistical testing of variance and covariance growth parameter estimates. Other practical issues pertaining to the three growth modeling methods are also discussed.  相似文献   

11.
Most growth models implicitly assume that test scores have been vertically scaled. What may not be widely appreciated are the different choices that must be made when creating a vertical score scale. In this paper empirical patterns of growth in student achievement are compared as a function of different approaches to creating a vertical scale. Longitudinal item‐level data from a standardized reading test are analyzed for two cohorts of students between Grades 3 and 6 and Grades 4 and 7 for the entire state of Colorado from 2003 to 2006. Eight different vertical scales were established on the basis of choices made for three key variables: Item Response Theory modeling approach, linking approach, and ability estimation approach. It is shown that interpretations of empirical growth patterns appear to depend upon the extent to which a vertical scale has been effectively “stretched” or “compressed” by the psychometric decisions made to establish it. While all of the vertical scales considered show patterns of decelerating growth across grade levels, there is little evidence of scale shrinkage.  相似文献   

12.
Through pilot studies and regular examination procedures, the National Institute for Educational Measurement (CITO) in The Netherlands has gathered experience with different methods of maintaining the standards of examinations. The present paper presents an overview of the psychometric aspects of the various approaches that can be chosen for the maintenance of standards. Generally speaking, the approaches to the problem, can be divided into two classes. In the first approach the examinations are a fixed factor, i.e. the examination is already constructed and cannot be changed, and the link between the standards of both examinations is created by some test equating design. In the second approach the items of both examinations are selected from a pre‐tested pool of items, in such a way that two equivalent examinations are constructed. In both approaches the statistical problems of simultaneously modelling possible differences in the ability level of different groups of examinees and differences in the difficulty of the items are solved within the framework of item response theory. It is shown that applying the Rasch model for dichotomous and polytomous items results in a variety of possible test‐equating designs which adequately deal with the restrictions imposed by the practical conditions related to the fact that the equating involves examinations. Especially the requirement of secrecy of the content of new examinations must be taken into account. Finally it is shown that, given a pool of pre‐tested items, optimisation techniques can be used to construct equivalent examinations.  相似文献   

13.
Evidence‐based practice approaches to interventions has come of age and promises to provide a new standard of excellence for school psychologists. This article describes several definitions of evidence‐based practice and the problems associated with traditional statistical analyses that rely on rejection of the null hypothesis for the establishment of invention effectiveness. Meta‐analysis as an approach to ascertain EBPs is reviewed along with the inherent difficulties associated with single subject design research such as autocorrelations. Four meta‐analytic approaches are reviewed which include Percentage of Nonoverlapping Data points (PND), the Busk and Serlin: Assumption models, ITSACORR, and Hierarchical Linear Modeling (HLM). HLM is offered as the most promising approach for the analysis for single subject designs. Monte Carlo simulations are modeled with varying degrees of autocorrelations, differing numbers of data points, and simulated effects sizes to show that HLM is an acceptable approach for controlling the risk of Type I errors. © 2007 Wiley Periodicals, Inc. Psychol Schs 44: 483–493, 2007.  相似文献   

14.
Mixture modeling is a widely applied data analysis technique used to identify unobserved heterogeneity in a population. Despite mixture models' usefulness in practice, one unresolved issue in the application of mixture models is that there is not one commonly accepted statistical indicator for deciding on the number of classes in a study population. This article presents the results of a simulation study that examines the performance of likelihood-based tests and the traditionally used Information Criterion (ICs) used for determining the number of classes in mixture modeling. We look at the performance of these tests and indexes for 3 types of mixture models: latent class analysis (LCA), a factor mixture model (FMA), and a growth mixture models (GMM). We evaluate the ability of the tests and indexes to correctly identify the number of classes at three different sample sizes (n = 200, 500, 1,000). Whereas the Bayesian Information Criterion performed the best of the ICs, the bootstrap likelihood ratio test proved to be a very consistent indicator of classes across all of the models considered.  相似文献   

15.
Recent advances in statistical methodology, in particular, latent growth modeling, allow for the testing of complex models regarding developmental trends from both an inter‐ and intraindividual perspective. An example application of latent growth curve methodology, analyzing the effects of gender and parental monitoring on developmental change in adolescent alcohol consumption, is presented. Furthermore, the analyses are conducted within a cohort‐sequential design, incorporating an approach to the analysis of missing data due to attrition. Findings are discussed with particular reference to the utility of latent growth curve models for assessing developmental processes at both the inter‐and intraindividual level across a variety of behavioral domains.  相似文献   

16.
Students’ performance in assessments is commonly attributed to more or less effective teaching. This implies that students’ responses are significantly affected by instruction. However, the assumption that outcome measures indeed are instructionally sensitive is scarcely investigated empirically. In the present study, we propose a longitudinal multilevel‐differential item functioning (DIF) model to combine two existing yet independent approaches to evaluate items’ instructional sensitivity. The model permits for a more informative judgment of instructional sensitivity, allowing the distinction of global and differential sensitivity. Exemplarily, the model is applied to two empirical data sets, with classical indices (Pretest–Posttest Difference Index and posttest multilevel‐DIF) computed for comparison. Results suggest that the approach works well in the application to empirical data, and may provide important information to test developers.  相似文献   

17.
Student‐centred learning has the potential to engage a more academically diverse student body than the more conventional teacher‐centred approaches. In spite of the evidence in favour of student‐centred learning, a recent study showed that it was ineffective for around 30% of undergraduates in a large and diverse group studying business operations management. The possible reasons for this are explored in two ways. First, the literature relating to student engagement and participation is reviewed from three different perspectives: the sociological, the epistemological and the approaches to learning perspectives. Second, all three perspectives are applied to data generated from the original study within the context of a post‐1992 university. The advantages of a three‐perspective approach over a single‐perspective approach are discussed. Finally, the development of a holistic model integrating all three perspectives is called for, to be used as a guide for further empirical research into student engagement and as a tool for evaluating and developing inclusive and engaging learning environments.  相似文献   

18.
Although methodology articles have increasingly emphasized the need to analyze data from two members of a dyad simultaneously, the most popular method in substantive applications is to examine dyad members separately. This might be due to the underappreciation of the extra information simultaneous modeling strategies can provide. Therefore, the goal of this study was to compare multiple growth curve modeling approaches for longitudinal dyadic data (LDD) in both structural equation modeling and multilevel modeling frameworks. Models separately assessing change over time for distinguishable dyad members are compared to simultaneous models fitted to LDD from both dyad members. Furthermore, we compared the simultaneous default versus dependent approaches (whether dyad pairs’ Level 1 [or unique] residuals are allowed to covary and differ in variance). Results indicated that estimates of variance and covariance components led to conflicting results. We recommend the simultaneous dependent approach for inferring differences in change over time within a dyad.  相似文献   

19.
The use of appropriate indicators of public and private expenditures, from which statistically significant differences in funding policies can be identified, constitutes a solid foundation in which the assessment of the role of governments in promoting higher education can be grounded. Based on a carefully selected set of Organization for Economic Co‐operation and Development indicators, this paper explores the effects of education funding policies, along with research and development expenditures and tax levels, on the entry rate to higher education. The results from the statistical analysis of the data confirm the existence of two distinct approaches to higher education funding, the Scandinavian approach and Anglo–American approach, and help to define their characteristics.  相似文献   

20.
There are differences of opinion about self‐esteem enhancement in the classroom; these differences exist at both conceptual and practical levels. The aim of this study was to ascertain whether techniques employed by primary school teachers as a day‐to‐day part of their teaching can have measurable effects on the self‐esteem of their pupils. Two different approaches to self‐esteem enhancement in primary classes were evaluated. The participants were 519 primary school children and their teachers (n = 21). Circle‐Time and efficacy‐based approaches were compared with a control condition over a four‐month period. On two self‐report measures of self‐esteem, gains were found for both experimental conditions, but not for the controls. Significant sub‐scale differences suggested that the two approaches achieved their effects in different ways, consistent with a two‐dimensional model of self‐esteem. Circle‐Time methodology, focusing on the creation of a climate in which individuals are respected and valued, is more likely to help children to develop a sense of self‐worth. On the other hand, an efficacy‐based approach tends to focus on the achievement of performance goals, and is thus more likely to develop the self‐competence dimension. It is argued that we should now reconsider how we think about self‐esteem enhancement in primary classrooms.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号