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1.
The shared parameter growth mixture model (SPGMM) has been proposed as a method to handle missing not at random (MNAR) data in longitudinal studies. This Monte Carlo simulation study compared the one-step approach with a three-step approach for adding covariates into the SPGMM. The results showed that performances of one-step and three-step approaches did not differ, but the estimate of the coefficient of the covariate was biased in most conditions with MNAR data. However, means, variances, and covariance of the intercept and slope as well as their standard errors were estimated without bias in most conditions, except for some combinations of small class distances and MNAR dropout missingness that was not related to the underlying growth trajectory. Classification accuracy was similar with both one-step and three-step SPGMM.  相似文献   

2.
Missing data are common in studies that rely on multiple informant data to evaluate relationships among variables for distinguishable individuals clustered within groups. Estimation of structural equation models using raw data allows for incomplete data, and so all groups can be retained for analysis even if only 1 member of a group contributes data. Statistical inference is based on the assumption that data are missing completely at random or missing at random. Importantly, whether or not data are missing is assumed to be independent of the missing data. A saturated correlates model that incorporates correlates of the missingness or the missing data into an analysis and multiple imputation that might also use such correlates offer advantages over the standard implementation of SEM when data are not missing at random because these approaches could result in a data analysis problem for which the missingness is ignorable. This article considers these approaches in an analysis of family data to assess the sensitivity of parameter estimates and statistical inferences to assumptions about missing data, a strategy that could be easily implemented using SEM software.  相似文献   

3.
This article examines whether Bayesian estimation with minimally informed prior distributions can alleviate the estimation problems often encountered with fitting the true score multitrait–multimethod structural equation model with split-ballot data. In particular, the true score multitrait–multimethod structural equation model encounters an empirical underidentification when (a) latent variable correlations are homogenous, and (b) fitted to data from a 2-group split-ballot design; an understudied case of empirical underidentification due to a planned missingness (i.e., split-ballot) design. A Monte Carlo simulation and 3 empirical examples showed that Bayesian estimation performs better than maximum likelihood (ML) estimation. Therefore, we suggest using Bayesian estimation with minimally informative prior distributions when estimating the true score multitrait–multimethod structural equation model with split-ballot data. Furthermore, given the increase in planned missingness designs in psychological research, we also suggest using Bayesian estimation as a potential alternative to ML estimation for analyses using data from planned missingness designs.  相似文献   

4.
The purpose of this study is to investigate the effects of missing data techniques in longitudinal studies under diverse conditions. A Monte Carlo simulation examined the performance of 3 missing data methods in latent growth modeling: listwise deletion (LD), maximum likelihood estimation using the expectation and maximization algorithm with a nonnormality correction (robust ML), and the pairwise asymptotically distribution-free method (pairwise ADF). The effects of 3 independent variables (sample size, missing data mechanism, and distribution shape) were investigated on convergence rate, parameter and standard error estimation, and model fit. The results favored robust ML over LD and pairwise ADF in almost all respects. The exceptions included convergence rates under the most severe nonnormality in the missing not at random (MNAR) condition and recovery of standard error estimates across sample sizes. The results also indicate that nonnormality, small sample size, MNAR, and multicollinearity might adversely affect convergence rate and the validity of statistical inferences concerning parameter estimates and model fit statistics.  相似文献   

5.
Local‐influence diagnostics based on maximum likelihood (ML), generalized least squares (GLS), and unweighted least squares (ULS) fit functions are developed for structural equation models (SEMs). The influence of observations, components of observations, and variables is considered. The diagnostics are illustrated with an example data set, and comparisons are made with equivalent global measures of influence. The local influence of the data set on ML and GLS estimates is very similar, but it is much different from that of ULS. The local and global influence of observations is also very different. Although it is not possible to define a uniformly best measure of influence, the local‐influence diagnostics developed here are more versatile than global‐influence diagnostics in assessing an analysis with SEMs.  相似文献   

6.
Competence data from low‐stakes educational large‐scale assessment studies allow for evaluating relationships between competencies and other variables. The impact of item‐level nonresponse has not been investigated with regard to statistics that determine the size of these relationships (e.g., correlations, regression coefficients). Classical approaches such as ignoring missing values or treating them as incorrect are currently applied in many large‐scale studies, while recent model‐based approaches that can account for nonignorable nonresponse have been developed. Estimates of item and person parameters have been demonstrated to be biased for classical approaches when missing data are missing not at random (MNAR). In our study, we focus on parameter estimates of the structural model (i.e., the true regression coefficient when regressing competence on an explanatory variable), simulating data according to various missing data mechanisms. We found that model‐based approaches and ignoring missing values performed well in retrieving regression coefficients even when we induced missing data that were MNAR. Treating missing values as incorrect responses can lead to substantial bias. We demonstrate the validity of our approach empirically and discuss the relevance of our results.  相似文献   

7.
This article focuses on the theoretical frame of action research and the teacher as researcher, working through a Norwegian Research Council‐funded project in a school that explored learning strategies for pupils’ subject and social development. Action research is here called research and development (R&D) work as the term envisages that research and development are being conducted at the same time. Additionally, the term reflects the fact that the research is conducted within the framework of activity theory and Engeström’s expansive learning circle in which work is termed R&D. The article describes the possibilities and challenges for both teachers and researchers cooperating in R&D projects. Reflection on observed teaching are presented as a central activity in development work, covering the form and content of reflective dialogues; quotations from teachers are provided to show how the teachers experienced observation and reflection. The article discusses whether teachers become researchers, or whether they only develop in their role as teachers. The close cooperation between teachers and researchers in this work is also presented as a model for further education for teachers in‐service and for the training of teacher students.  相似文献   

8.
Rubin’s classic missingness mechanisms are central to handling missing data and minimizing biases that can arise due to missingness. However, the formulaic expressions that posit certain independencies among missing and observed data are difficult to grasp. As a result, applied researchers often rely on informal translations of these assumptions. We present a graphical representation of missing data mechanism, formalized in Mohan, Pearl, and Tian (2013). We show that graphical models provide a tool for comprehending, encoding, and communicating assumptions about the missingness process. Furthermore, we demonstrate on several examples how graph-theoretical criteria can determine if biases due to missing data might emerge in some estimates of interests and which auxiliary variables are needed to control for such biases, given assumptions about the missingness process.  相似文献   

9.
The analysis of longitudinal data collected from nonexchangeable dyads presents a challenge for applied researchers for various reasons. This article introduces the dyadic curve-of-factors model (D–COFM), which extends the curve-of-factors model (COFM) proposed by McArdle (1988) for use with nonexchangeable dyadic data. The D–COFM overcomes problems with modeling composite scores across time and instead permits examination of the growth in latent constructs over time. The D–COFM also appropriately models the interdependency among nonexchangeable dyads. Different parameterizations of the D–COFM are illustrated and discussed using a real data set to aid applied researchers when analyzing dyadic longitudinal data.  相似文献   

10.
A procedure for evaluating candidate auxiliary variable correlations with response variables in incomplete data sets is outlined. The method provides point and interval estimates of the outcome-residual correlations with potentially useful auxiliaries, and of the bivariate correlations of outcome(s) with the latter variables. Auxiliary variables found in this way can enhance considerably the plausibility of the popular missing at random (MAR) assumption if included in ensuing maximum likelihood analyses, or can alternatively be incorporated in imputation models for subsequent multiple imputation analyses. The approach can be particularly helpful in empirical settings where violations of the MAR assumption are suspected, as is the case in many longitudinal studies, and is illustrated with data from cognitive aging research.  相似文献   

11.
This article presents a critical case study of an inner city state school that for a decade (1940s–1950s) attracted the interest of a wide contingency of educationalists, policy makers, researchers, artists and various press and film media. It has been argued that if we are to progress ‘social alternatives’ in education, researchers need to construct ‘critical case studies of possibilities’ drawing inspiration from traces of experimental and utopian practice in schools from the past as well as the present. The article demonstrates how this might be achieved through research that questions dominant narratives, goes beyond the public accounts of particular sites of experimentation and explores multiple‐narratives embedded in the records of past practice. The authors argue that such situated counter‐currents in the history of education are necessary both to inform our collective notions of past experience and enrich our regard for future possibilities.  相似文献   

12.
Mixed-dyadic data, collected from distinguishable (nonexchangeable) or indistinguishable (exchangeable) dyads, require statistical analysis techniques that model the variation within dyads and between dyads appropriately. The purpose of this article is to provide a tutorial for performing structural equation modeling analyses of cross-sectional and longitudinal models for mixed independent variable dyadic data, and to clarify questions regarding various dyadic data analysis specifications that have not been addressed elsewhere. Artificially generated data similar to the Newlywed Project and the Swedish Adoption Twin Study on Aging were used to illustrate analysis models for distinguishable and indistinguishable dyads, respectively. Due to their widespread use among applied researchers, the AMOS and Mplus statistical analysis software packages were used to analyze the dyadic data structural equation models illustrated here. These analysis models are presented in sufficient detail to allow researchers to perform these analyses using their preferred statistical analysis software package.  相似文献   

13.
Recent studies have analyzed social and dimensional comparisons simultaneously in order to consider their impact on students' academic self-concept (e.g., Chiu, 2012). Thereby, social comparisons refer to comparisons with the achievement level of students' classmates, whereas dimensional comparisons comprise comparisons between students' individual achievements across different domains. This paper analyzes whether both achievement comparisons influence students' subject-interest in mathematics and English (as a first foreign language). The analyses are based on N = 1390 German fifth and sixth grade students who participated in the BiKS-8-14 longitudinal study. Using multi-level analyses, results indicate that students' competences influence their mathematical and English subject-interests, demonstrating the typical pattern of social and dimensional comparisons. Further, analyses reveal mediation effects by subject-specific grades and self-concepts. These findings also apply for the development of students' subject-interest from grade 5 to grade 6. Results are discussed with respect to their implications concerning theories of achievement comparisons and interest development.  相似文献   

14.
This article investigates three types of stage-sequential growth mixture models in the structural equation modeling framework for the analysis of multiple-phase longitudinal data. These models can be important tools for situations in which a single-phase growth mixture model produces distorted results and can allow researchers to better understand population heterogeneity and growth over multiple phases. Through theoretical and empirical comparisons of the models, the authors discuss strategies with respect to model selection and interpreting outcomes. The unique attributes of each approach are illustrated using ecological momentary assessment data from a tobacco cessation study. Transitional discrepancy between phases as well as growth factors are examined to see whether they can give us useful information related to a distal outcome, abstinence at 6 months postquit. It is argued that these statistical models are powerful and flexible tools for the analysis of complex and detailed longitudinal data.  相似文献   

15.
In this article we propose that in order to advance our understanding of motivation in collaborative learning we should move beyond the cognitive–situative epistemological divide and combine individual and social processes. Our claim is that although recent research has recognized the importance of social aspects in emerging and sustained motivation in collaborative learning activities, the social is mainly conceived as a unidirectional source of influence on individual motivation. In the article we examine the significance of motivation in research on collaborative learning. We discuss two characterizations of the role of the social in conceptualizations of motivation, namely, social influence and social construction, and outline our case for moving beyond the cognitive–situative divide and combining individual and social processes in research on motivation. Finally, we present illustrations from recent research on motivation in collaborative learning that has attempted to bridge the cognitive–situative divide across theoretical perspectives or using different methods.  相似文献   

16.
In longitudinal design, investigating interindividual differences of intraindividual changes enables researchers to better understand the potential variety of development and growth. Although latent growth curve mixture models have been widely used, unstructured finite mixture models (uFMMs) are also useful as a preliminary tool and are expected to be more robust in identifying classes under the influence of possible model misspecifications, which are very common in actual practice. In this study, large-scale simulations were performed in which various normal uFMMs and nonnormal uFMMs were fit to evaluate their utility and the performance of each model selection procedure for estimating the number of classes in longitudinal designs. Results show that normal uFMMs assuming invariance of variance–covariance structures among classes perform better on average. Among model selection procedures, the Calinski–Harabasz statistic, which has a nonparametric nature, performed better on average than information criteria, including the Bayesian information criterion.  相似文献   

17.
The purpose of this article is to respond to Bernice Wong's questions regarding the efficacy of the risk and resilience model for studying social problems in students with learning disabilities. Two factors render this framework particularly inviting to special education researchers. First, it is inherently optimistic because it assumes that once we identify factors that contribute to resilience, we can train less‐resistant individuals to be more resilient. As such, it moves us away from deficit models to empowering models. Second, the model forces us to look beyond the characteristics of the individual to consider external factors that have a significant influence on development and behavior. At the same time, however, we still need to advance our knowledge regarding the basic dimensions of social problems among students with learning disabilities. Hence, this article argues for multiple approaches to advancing knowledge about students with learning disabilities.  相似文献   

18.
Most researchers who have investigated the relationship between the media and education have asserted that coverage of education has a negative impact on public perceptions of, and support for, public education. Much of this research relies on negative case examples and cross-sectional data to make this claim. This article calls into question the assumptions being made by these researchers. The article identifies a need for more systematic and longitudinal research on the topic. In identifying this need, the article suggests the development of a framework that recognizes the appropriate role of the media in a democratic society. In developing this framework, it is recommended that researchers focus on both media processes and media impacts in assessing the democratic nature of the coverage provided.  相似文献   

19.
This article uses the views of student teachers and serving teachers from a post‐Soviet context in order to better understand current thinking around teachers’ perceptions of children with what might be termed ‘hidden’ disabilities. Drawing on social comparison theory, and adopting a phenomenographical approach, the study explores teachers’ perspectives of autism in the Republic of Armenia, offering an insight into the impact of its social, cultural and political history. Whilst serving teachers demonstrated contrastive and downward comparisons when presented with a vignette of a young person with Asperger's Syndrome, student teachers expressed more connective comparisons. The data suggest, then, that Armenian student teachers represent progressive attitudinal change towards individuals with disabilities. These results also shed light on how social comparison theory might be used to tease out assumptions and taken‐for‐granted attitudes in the global West.  相似文献   

20.
Significant changes in state economic priorities are likely to have a formative and fateful effect on institutions of higher education. Yet economic accounts cannot themselves explain changes in the economic priorities of nationalist states, in part because of the ideological character of such states. The nationalist state's influence on institutions of higher education is often indirect, involving the interactions of social and political actors who are themselves influenced by prevailing social ideologies. Social ideologies contribute to shifts in state economic priorities, and these changes can indirectly but significantly influence the trajectory of institutions of higher education. A longitudinal case study of a Canadian distanceeducation university demonstrates the means by which nationalist sentiment encouraged a shift in state economic priorities, which in turn created a welcoming social climate for a new university's consumerist model of education.  相似文献   

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