The Integration of Continuous and Discrete Latent Variable Models: Potential Problems and Promising Opportunities.

Structural equation mixture modeling (SEMM) integrates continuous and discrete latent variable models. Drawing on prior research on the relationships between continuous and discrete latent variable models, the authors identify 3 conditions that may lead to the estimation of spurious latent classes in SEMM: misspecification of the structural model, nonnormal continuous measures, and nonlinear relationships among observed and/or latent variables. When the objective of a SEMM analysis is the identification of latent classes, these conditions should be considered as alternative hypotheses and results should be interpreted cautiously. However, armed with greater knowledge about the estimation of SEMMs in practice, researchers can exploit the flexibility of the model to gain a fuller understanding of the phenomenon under study. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analyzing the convergent and discriminant validity of states and traits: Development and applications of multimethod latent state-trait models.

The analysis of convergent and discriminant validity is an integral part of the construct validation process. Models for analyzing the convergent and discriminant validity have typically been developed for cross-sectional data. There exist, however, only a few approaches for longitudinal data that can be applied for analyzing the construct validity of fluctuating states. In this article, the authors show how models of latent state-trait theory can be combined with models of multitrait-multimethod analysis to develop a model that allows for analyzing convergent and discriminant validity in time: the multimethod latent state-trait model. The model allows for identifying different sources of variance (trait consistency, trait-method specificity, occasion-specific consistency, occasion-specific method specificity, and unreliability). It is applied to the repeated measurement of depression and anxiety in children, which was assessed by self and teacher reports (N = 375). The application shows that the proposed models fit the data well and allow a deeper understanding of method effects in clinical assessment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Longitudinal Structure of the Children's Depression Inventory: Testing a Latent Trait-State Model.

In a 6-wave longitudinal study, children (Grades 4-6, n=648), adolescents (Grades 7-9, n=1,489), and their parents completed child-adolescent or parent versions of the Children's Depression Inventory (CDI; M. Kovacs, 1981). Using structural equation modeling, the authors conducted latent trait-state analyses to distinguish between a stable trait dimension of depression (in which individual differences are stable over time) and an autoregressive dimension (in which individual differences are less stable over time). Children's CDIs reflected the autoregressive dimension more than a stable trait dimension, whereas parents' CDIs reflected a stable trait dimension more than an autoregressive dimension. Reports from adolescents and their parents reflected a stable trait dimension more than an autoregressive dimension of depressive symptoms. Results suggest that the longitudinal structure of the CDI varies considerably depending on the age of the target and the type of informant. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Testing Mediational Models With Longitudinal Data: Questions and Tips in the Use of Structural Equation Modeling.

R. M. Baron and D. A. Kenny (1986; see record 1987-13085-001) provided clarion conceptual and methodological guidelines for testing mediational models with cross-sectional data. Graduating from cross-sectional to longitudinal designs enables researchers to make more rigorous inferences about the causal relations implied by such models. In this transition, misconceptions and erroneous assumptions are the norm. First, we describe some of the questions that arise (and misconceptions that sometimes emerge) in longitudinal tests of mediational models. We also provide a collection of tips for structural equation modeling (SEM) of mediational processes. Finally, we suggest a series of 5 steps when using SEM to test mediational processes in longitudinal designs: testing the measurement model, testing for added components, testing for omitted paths, testing the stationarity assumption, and estimating the mediational effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Longitudinal tests of competing factor structures for the Rosenberg Self-Esteem Scale: Traits, ephemeral artifacts, and stable response styles.

Self-esteem, typically measured by the Rosenberg Self-Esteem Scale (RSE), is one of the most widely studied constructs in psychology. Nevertheless, there is broad agreement that a simple unidimensional factor model, consistent with the original design and typical application in applied research, does not provide an adequate explanation of RSE responses. However, there is no clear agreement about what alternative model is most appropriate—or even a clear rationale for how to test competing interpretations. Three alternative interpretations exist: (a) 2 substantively important trait factors (positive and negative self-esteem), (b) 1 trait factor and ephemeral method artifacts associated with positively or negatively worded items, or (c) 1 trait factor and stable response-style method factors associated with item wording. We have posited 8 alternative models and structural equation model tests based on longitudinal data (4 waves of data across 8 years with a large, representative sample of adolescents). Longitudinal models provide no support for the unidimensional model, undermine support for the 2-factor model, and clearly refute claims that wording effects are ephemeral, but they provide good support for models positing 1 substantive (self-esteem) factor and response-style method factors that are stable over time. This longitudinal methodological approach has not only resolved these long-standing issues in self-esteem research but also has broad applicability to most psychological assessments based on self-reports with a mix of positively and negatively worded items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relations of television viewing and reading: Findings from a 4-year longitudinal study.

This longitudinal study explored the long-term effects of television viewing on the development of children's reading competencies. Among 2 cohorts of German children (N? = 165, N? = 167), measures of television viewing were collected over 4 years, and tests of reading speed and reading comprehension were administered annually. As a main result, TV genre (educational vs. entertainment programs) produced different effects. Whereas educational program viewing was positively correlated with reading achievement, relations between entertainment program viewing and reading performance were generally negative. Children who were classified as heavy viewers (average viewing time per day = 117 min) showed lower progress in reading over time as compared to medium and light viewers (average viewing times per day 69 and 35 min, respectively). Partial support was found only for 1 of the 3 tested causal mechanisms, namely television-induced reduction in leisure-time book reading. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analyzing true change in longitudinal multitrait-multimethod studies: Application of a multimethod change model to depression and anxiety in children.

The authors show how structural equation modeling can be applied to analyze change in longitudinal multitrait-multimethod (MTMM) studies. For this purpose, an extension of latent difference models (McArdle, 1988; Steyer, Eid, & Schwenkmezger, 1997) to multiple constructs and multiple methods is presented. The model allows investigators to separate true change from measurement error and to analyze change simultaneously for different methods. The authors also show how Campbell and Fiske’s (1959) guidelines for analyzing convergent and discriminant validity can be applied to the measurement of latent change. The practical application of the multimethod change model is illustrated in a reanalysis of child depression and anxiety scores (N = 906 American children) that were assessed by self- and parent reports on three measurement occasions. The analyses revealed that (a) the convergent validity of change was low for both constructs and (b) sex was a significant predictor of self-reported, but not of parent reported, anxiety states. Finally, the authors discuss advantages and limitations and compare the model with other approaches for analyzing longitudinal MTMM data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structural Equation Models of Latent Interactions: Evaluation of Alternative Estimation Strategies and Indicator Construction.

Interactions between (multiple indicator) latent variables are rarely used because of implementation complexity and competing strategies. Based on 4 simulation studies, the traditional constrained approach performed more poorly than did 3 new approaches-unconstrained, generalized appended product indicator, and quasi-maximum-likelihood (QML). The authors' new unconstrained approach was easiest to apply. All 4 approaches were relatively unbiased for normally distributed indicators, but the constrained and QML approaches were more biased for nonnormal data; the size and direction of the bias varied with the distribution but not with the sample size. QML had more power, but this advantage was qualified by consistently higher Type I error rates. The authors also compared general strategies for defining product indicators to represent the latent interaction factor. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Latent Markov Model for the Analysis of Longitudinal Data Collected in Continuous Time: States, Durations, and Transitions.

Markov models provide a general framework for analyzing and interpreting time dependencies in psychological applications. Recent work extended Markov models to the case of latent states because frequently psychological states are not directly observable and subject to measurement error. This article presents a further generalization of latent Markov models to allow for the analysis of rating data that are collected at arbitrary points in time. This extension offers new ways of investigating change processes by focusing explicitly on the durations that are spent in latent states. In an experience sampling application the author shows that such duration analyses can provide valuable insights about chronometric features of emotions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Testing a Four-Factor Model of Psychopathy and Its Association With Ethnicity, Gender, Intelligence, and Violence.

Although a 2-factor model has advanced research on the psychopathy construct, a 3-factor model was recently developed that emphasized pathological personality and eliminated antisocial behavior. However, dropping antisocial behavior from the psychopathy construct may not be advantageous. Using a large sample of psychiatric patients from the MacArthur Risk Assessment Study (J. Monahan & H. J. Steadman, 1994), the authors used confirmatory factor analysis to test a 4-factor model of psychopathy, which included interpersonal, affective, and behavioral impulsivity dimensions and an antisocial behavior dimension. Model fit was good for this 4-factor model, even when ethnicity, gender, and intelligence variables were included in the model. Structural equation modeling was used to compare the 3- and 4-factor models in predicting proximal (violence) and distal (intelligence) correlates of psychopathy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Six of One, Half a Dozen of the Other: Problems With Working Fixed and Rotating Shifts.

This study examined the relationship between shift patterns and role stressors and strains, as well as the extent to which situational variables and individual variables mediate the relationship between shift patterns and strains. Using survey data from 397 Israeli nurses, the author found that nurses working fixed day (vs. rotating) shifts reported less strains, but more stressors. Individual and situational variables mediated the relationship between shift pattern and both affective commitment and intention to leave, respectively. Younger age and higher role ambiguity might account for fully rotating shift nurses' reports of intention to leave, and being an older, full-time employee with little role conflict and ambiguity might explain why fixed day (vs. rotating) shift nurses report greater affective commitment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Testing differences between nested covariance structure models: Power analysis and null hypotheses.

For comparing nested covariance structure models, the standard procedure is the likelihood ratio test of the difference in fit, where the null hypothesis is that the models fit identically in the population. A procedure for determining statistical power of this test is presented where effect size is based on a specified difference in overall fit of the models. A modification of the standard null hypothesis of zero difference in fit is proposed allowing for testing an interval hypothesis that the difference in fit between models is small, rather than zero. These developments are combined yielding a procedure for estimating power of a test of a null hypothesis of small difference in fit versus an alternative hypothesis of larger difference. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Childhood Sexual Abuse, Disordered Eating, Alexithymia, and General Distress: A Mediation Model.

Drawing from trauma-related theory (e.g., M. F. Schwartz & P. Gay, 1996), this article presents a model of associations among child sexual abuse (CSA), psychological distress, alexithymia, and disordered eating (DE). Structural equation modeling was used to test this conceptual model with a sample of female college students (N = 589). Results indicate that CSA is not directly associated with DE. Instead, CSA is associated with psychological distress, which is further related to alexithymia. Additionally, bootstrapping analyses were used to show that distress and alexithymia mediate the relationship between CSA and DE. Finally, restrictive eating behaviors and attitudes mediate between alexithymia and bulimic behaviors. This latter pathway was shown to be important to the model by the analysis of a 2nd, nested model. Although this model is only one of many possible, these results point to a weak but significant complex relation between CSA and DE. (PsycINFO Database Record (c) 2010 APA, all rights reserved)