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1.
Multivariate Behav Res ; 58(6): 1106-1133, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37038722

RESUMO

For multilevel models (MLMs) with fixed slopes, it has been widely recognized that a level-1 variable can have distinct between-cluster and within-cluster fixed effects, and that failing to disaggregate these effects yields a conflated, uninterpretable fixed effect. For MLMs with random slopes, however, we clarify that two different types of slope conflation can occur: that of the fixed component (termed fixed conflation) and that of the random component (termed random conflation). The latter is rarely recognized and not well understood. Here we explain that a model commonly used to disaggregate the fixed component-the contextual effect model with random slopes-troublingly still yields a conflated random component. Negative consequences of such random conflation have not been demonstrated. Here we show that they include erroneous interpretation and inferences about the substantively important extent of between-cluster differences in slopes, including either underestimating or overestimating such slope heterogeneity. Furthermore, we show that this random conflation can yield inappropriate standard errors for fixed effects. To aid researchers in practice, we delineate which types of random slope specifications yield an unconflated random component. We demonstrate the advantages of these unconflated models in terms of estimating and testing random slope variance (i.e., improved power, Type I error, and bias) and in terms of standard error estimation for fixed effects (i.e., more accurate standard errors), and make recommendations for which specifications to use for particular research purposes.


Assuntos
Modelos Estatísticos , Interpretação Estatística de Dados , Análise Multinível , Viés
2.
Multivariate Behav Res ; 58(2): 340-367, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35476605

RESUMO

Applications of multilevel models (MLMs) with three or more levels have increased alongside expanding software capability and dataset availability. Though researchers often express interest in R-squared measures as effect sizes for MLMs, R-squareds previously proposed for MLMs with three or more levels cover a limited subset of choices for how to quantify explained variance in these models. Additionally, analytic relationships between total and level-specific versions of MLM R-squared measures have not been clarified, despite such relationships becoming increasingly important to understand when there are more levels. Furthermore, the impact of predictor centering strategy on R-squared computation and interpretation has not been explicated for MLMs with any number of levels. To fill these gaps, we extend the Rights and Sterba two-level MLM R-squared framework to three or more levels, providing a general set of measures that includes preexisting three-level measures as special cases and yields additional results not obtainable from existing measures. We mathematically and pedagogically relate total and level-specific R-squareds, and show how all total and level-specific R-squared measures in our framework can be computed under any centering strategy. Finally, we provide and empirically demonstrate software (available in the r2mlm R package) to compute measures and graphically depict results.


Assuntos
Modelos Estatísticos , Análise Multinível
3.
Int J Eat Disord ; 55(12): 1721-1732, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36165444

RESUMO

OBJECTIVE: Comorbidity of disordered eating (DE) behaviors and nonsuicidal self-injury (NSSI) is linked to increased functional impairment. The present study identified subtypes of DE and NSSI comorbidity in a non-Western, low- and middle-income country where there has been particularly little research in this area. METHOD: Latent profile analyses (LPA) were conducted to identify patterns of subgroup comorbidity in self-reported DE behaviors and NSSI behaviors, in a sample of Vietnamese high-school students (N = 1451, 51% female). Parallel-process LPA was used to predict NSSI subgroup membership from DE subgroup membership. RESULTS: A seven-class LPA model was identified for DE: (1) Low frequencies of all DE behaviors; (2) Frequent levels of all DE behaviors; (3) Frequent fasting and purging behaviors; (4) Frequent binge eating only; (5) Moderate binge eating; (6) Moderate fasting and purging behaviors; (7) Exercise and fasting. A two-class (high versus low) model was identified for NSSI. Odds of membership in the high-NSSI class were significantly increased for all DE classes except the class characterized by moderate binge eating. Odds of belonging to the high-NSSI class were highest for those in DE classes involving purging behaviors. Males predominated in classes characterized by high behavior dysregulation. DISCUSSION: DE and NSSI represent important clinical concerns among Vietnamese youth in urban contexts, and males may show particular vulnerability for certain risk behaviors. The association of classes of DE behaviors to NSSI was particularly strong for classes that involved purging, highlighting the importance of this specific behavior for understanding comorbidity of DE and NSSI. PUBLIC SIGNIFICANCE: Disordered eating and nonsuicidal self-injury (NSSI; hurting oneself without intending to die) commonly co-occur. There has been less research on disordered eating and NSSI among individuals from non-Western or low/middle-income countries. We examined patterns of these behaviors in a school-based sample of Vietnamese adolescents. We found that patterns of disordered eating distinguished by purging showed particular links to NSSI, which could have implications for screening and treatment.


Assuntos
Transtornos da Alimentação e da Ingestão de Alimentos , Comportamento Autodestrutivo , Feminino , Humanos , Adolescente , Masculino , População do Sudeste Asiático , Comportamento Autodestrutivo/epidemiologia , Transtornos da Alimentação e da Ingestão de Alimentos/epidemiologia
4.
J Educ Psychol ; 113(1): 86-103, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33776137

RESUMO

The main purpose of this study was to test the effects of word-problem intervention, with versus without embedded language comprehension instruction, on at-risk 1st graders' word-problem performance. We also isolated the need for a structured approach to word-problem intervention and tested the efficacy of schema-based instruction at 1st grade. Children (n=391; mean age = 6.53, SD = 0.32) were randomly assigned to 4 conditions: schema-based word-problem intervention with embedded language instruction, the same word-problem intervention but without language comprehension instruction, structured number knowledge intervention without a structured word-problem component, and a control group. Each intervention included 45 30-min sessions. Multilevel models, accounting for classroom and school effects, revealed the efficacy of schema-based word-problem intervention at 1st grade, with both word-problem conditions outperforming the number knowledge condition and the control group. Yet, word-problem performance was significantly stronger for the schema-based condition with embedded language comprehension instruction compared to the schema-based condition without language comprehension instruction. Number knowledge intervention conveyed no word-problem advantage over the control group, even though all 3 intervention conditions outperformed the control group on arithmetic. Results demonstrate the importance of a structured approach to word-problem intervention; the efficacy of schema-based instruction at 1st grade; and the added value of language comprehension instruction within word-problem intervention. Results also provide causal evidence on the role of language comprehension in word-problem solving.

5.
New Dir Child Adolesc Dev ; 2021(175): 65-110, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33512773

RESUMO

Developmental researchers commonly utilize multilevel models (MLMs) to describe and predict individual differences in change over time. In such growth model applications, researchers have been widely encouraged to supplement reporting of statistical significance with measures of effect size, such as R-squareds (R2 ) that convey variance explained by terms in the model. An integrative framework for computing R-squareds in MLMs with random intercepts and/or slopes was recently introduced by Rights and Sterba and it subsumed pre-existing MLM R-squareds as special cases. However, this work focused on cross-sectional applications, and hence did not address how the computation and interpretation of MLM R-squareds are affected by modeling considerations typically arising in longitudinal settings: (a) alternative centering choices for time (e.g., centering-at-a-constant vs. person-mean-centering), (b) nonlinear effects of predictors such as time, (c) heteroscedastic level-1 errors and/or (d) autocorrelated level-1 errors. This paper addresses these gaps by extending the Rights and Sterba R-squared framework to longitudinal contexts. We: (a) provide a full framework of total and level-specific R-squared measures for MLMs that utilize any type of centering, and contrast these with Rights and Sterba's measures assuming cluster-mean-centering, (b) explain and derive which measures are applicable for MLMs with nonlinear terms, and extend the R-squared computation to accommodate (c) heteroscedastic and/or (d) autocorrelated errors. Additionally, we show how to use differences in R-squared (ΔR2 ) measures between growth models (adding, for instance, time-varying covariates as level-1 predictors or time-invariant covariates as level-2 predictors) to obtain effects sizes for individual terms. We provide R software (r2MLMlong) and a running pedagogical example analyzing growth in adolescent self-efficacy to illustrate these methodological developments. With these developments, researchers will have greater ability to consider effect size when analyzing and predicting change using MLMs.


Assuntos
Modelos Estatísticos , Adolescente , Estudos Transversais , Humanos , Análise Multinível
6.
Multivariate Behav Res ; 55(4): 568-599, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31559890

RESUMO

When comparing multilevel models (MLMs) differing in fixed and/or random effects, researchers have had continuing interest in using R-squared differences to communicate effect size and importance of included terms. However, there has been longstanding confusion regarding which R-squared difference measures should be used for which kind of MLM comparisons. Furthermore, several limitations of recent studies on R-squared differences in MLM have led to misleading or incomplete recommendations for practice. These limitations include computing measures that are by definition incapable of detecting a particular type of added term, considering only a subset of the broader class of available R-squared difference measures, and incorrectly defining what a given R-squared difference measure quantifies. The purpose of this paper is to elucidate and resolve these issues. To do so, we define a more general set of total, within-cluster, and between-cluster R-squared difference measures than previously considered in MLM comparisons and give researchers concrete step-by-step procedures for identifying which measure is relevant to which model comparison. We supply simulated and analytic demonstrations of limitations of previous MLM studies on R-squared differences and show how application of our step-by-step procedures and general set of measures overcomes each. Additionally, we provide and illustrate graphical tools and software allowing researchers to automatically compute and visualize our set of measures in an integrated manner. We conclude with recommendations, as well as extensions involving (a) how our framework relates to and can be used to obtain pseudo-R-squareds, and (b) how our framework can accommodate both simultaneous and hierarchical model-building approaches.


Assuntos
Pesquisa Comportamental/métodos , Modelos Estatísticos , Análise Multinível/métodos , Software/normas , Análise de Variância , Pesquisa Comportamental/estatística & dados numéricos , Criança , Pré-Escolar , Interpretação Estatística de Dados , Feminino , Humanos , Modelos Lineares , Masculino
7.
Multivariate Behav Res ; 54(2): 264-287, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30755036

RESUMO

In structural equation modeling applications, parcels-averages or sums of subsets of item scores-are often used as indicators of latent constructs. Parcel-allocation variability (PAV) is variability in results that arises within sample across alternative item-to-parcel allocations. PAV can manifest in all results of a parcel-level model (e.g., model fit, parameter estimates, standard errors, and inferential decisions). It is a source of uncertainty in parcel-level model results that can be investigated, reported, and accounted for. Failing to do so raises representativeness and replicability concerns. However, in recent methodological literature (Cole, Perkins, & Zelkowitz, 2016 ; Little, Rhemtulla, Gibson, & Shoemann, 2013 ; Marsh, Ludtke, Nagengast, Morin, & von Davier, 2013 ; Rhemtulla, 2016 ) parceling has been justified and recommended in several situations without quantifying or accounting for PAV. In this article, we explain and demonstrate problems with these rationales. Overall, we find that: (1) using a purposive parceling algorithm for a multidimensional construct does not avoid PAV; (2) passing a test of unidimensionality of the item-level model need not avoid PAV; and (3) a desire to improve power for detecting structural misspecification does not warrant parceling without addressing PAV; we show how to simultaneously avoid PAV and obtain even higher power by comparing item-level models differing in structural constraints. Implications for practice are discussed.


Assuntos
Algoritmos , Análise de Classes Latentes , Modelos Estatísticos , Humanos
8.
Psychol Methods ; 24(3): 309-338, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29999378

RESUMO

Researchers often mention the utility and need for R-squared measures of explained variance for multilevel models (MLMs). Although this topic has been addressed by methodologists, the MLM R-squared literature suffers from several shortcomings: (a) analytic relationships among existing measures have not been established so measures equivalent in the population have been redeveloped 2 or 3 times; (b) a completely full partitioning of variance has not been used to create measures, leading to gaps in the availability of measures to address key substantive questions; (c) a unifying approach to interpreting and choosing among measures has not been provided, leading to researchers' difficulty with implementation; and (d) software has inconsistently and infrequently incorporated available measures. We address these issues with the following contributions. We develop an integrative framework of R-squared measures for MLMs with random intercepts and/or slopes based on a completely full decomposition of variance. We analytically relate 10 existing measures from different disciplines as special cases of 5 measures from our framework. We show how our framework fills gaps by supplying additional total and level-specific measures that answer new substantive research questions. To facilitate interpretation, we provide a novel and integrative graphical representation of all the measures in the framework; we use it to demonstrate limitations of current reporting practices for MLM R-squareds, as well as benefits of considering multiple measures from the framework in juxtaposition. We supply and empirically illustrate an R function, r2MLM, that computes all measures in our framework to help researchers in considering effect size and conveying practical significance. (PsycINFO Database Record (c) 2019 APA, all rights reserved).


Assuntos
Bioestatística/métodos , Interpretação Estatística de Dados , Modelos Estatísticos , Análise Multinível , Psicologia/métodos , Avaliação Educacional/estatística & dados numéricos , Humanos , Estudantes/estatística & dados numéricos
9.
Behav Res Ther ; 111: 44-51, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30300779

RESUMO

Previous research has linked sleep disturbance to anxiety. However, evidence for this relation has been inconsistent, largely limited to retrospective reports that do not account for daily variability, and silent on when the association is most pronounced. Thus, the present study utilized ecological momentary assessment (EMA) to examine the effects of daily deviations in total sleep time (TST) and person-average TST on anxiety and whether these effects varied as a function of time of day in a sample of unselected adults (N = 138). Results indicate that the amount of TST on a given night, relative to personal average TST, negatively predicted anxiety, and this relation was significant in the morning and afternoon, but not evening. In contrast, person-average TST was unrelated to average anxiety. Relations between TST and anxiety did not differ across objective (e.g., actigraphy) and subjective (e.g., sleep diary) measures. Furthermore, the pattern of results remained the same when controlling for previous day's anxiety and were not bidirectional. These findings suggest that getting less sleep than is typical for the individual predicts subsequent anxiety, and this effect is particularly strong in the morning. Average sleep duration may be less important to the experience of anxiety than deviations from that average. These findings highlight the importance of EMA to examine how and when variability in sleep confers vulnerability for anxiety symptoms.


Assuntos
Ansiedade/psicologia , Fotoperíodo , Sono , Actigrafia , Adolescente , Adulto , Avaliação Momentânea Ecológica , Feminino , Humanos , Masculino , Prontuários Médicos , Pessoa de Meia-Idade , Adulto Jovem
10.
Appl Psychol Meas ; 42(2): 136-154, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29882542

RESUMO

The current study investigated the consequences of ignoring a multilevel structure for a mixture item response model to show when a multilevel mixture item response model is needed. Study 1 focused on examining the consequence of ignoring dependency for within-level latent classes. Simulation conditions that may affect model selection and parameter recovery in the context of a multilevel data structure were manipulated: class-specific ICC, cluster size, and number of clusters. The accuracy of model selection (based on information criteria) and quality of parameter recovery were used to evaluate the impact of ignoring a multilevel structure. Simulation results indicated that, for the range of class-specific ICCs examined here (.1 to .3), mixture item response models which ignored a higher level nesting structure resulted in less accurate estimates and standard errors (SEs) of item discrimination parameters when the number of clusters was larger than 24 and the cluster size was larger than six. Class-varying ICCs can have compensatory effects on bias. Also, the results suggested that a mixture item response model which ignored multilevel structure was not selected over the multilevel mixture item response model based on Bayesian information criterion (BIC) if the number of clusters and cluster size was at least 50, respectively. In Study 2, the consequences of unnecessarily fitting a multilevel mixture item response model to single-level data were examined. Reassuringly, in the context of single-level data, a multilevel mixture item response model was not selected by BIC, and its use would not distort the within-level item parameter estimates or SEs when the cluster size was at least 20. Based on these findings, it is concluded that, for class-specific ICC conditions examined here, a multilevel mixture item response model is recommended over a single-level item response model for a clustered dataset having cluster size >20 and the number of clusters >50 .

11.
Psychol Methods ; 23(3): 434-457, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28301198

RESUMO

Psychologists commonly apply regression mixture models in single-level (i.e., unclustered) and multilevel (i.e., clustered) data analysis contexts. Though researchers applying nonmixture regression models typically report R-squared measures of explained variance, there has been no general treatment of R-squared measures for single-level and multilevel regression mixtures. Consequently, it is common for researchers to summarize results of a fitted regression mixture by simply reporting class-specific regression coefficients and their associated p values, rather than considering measures of effect size. In this article, we fill this gap by providing an integrative framework of R-squared measures for single-level regression mixture models and multilevel regression mixture models (with classes at Level-2 or both levels). Specifically, we describe 11 R-squared measures that are distinguished based on what the researcher chooses to consider as outcome variance and what sources the researcher chooses to contribute to predicted variance. We relate these measures analytically and through simulated graphical illustrations. Further, we demonstrate how these R-squared measures can be decomposed in novel ways into substantively meaningful sources of explained variance. We describe and demonstrate new software tools to allow researchers to compute these R-squared measures and decompositions in practice. Using 2 empirical examples, we show how researchers can answer distinct substantive questions with each measure and can gain insights by interpreting the set of measures in juxtaposition to each other. (PsycINFO Database Record


Assuntos
Interpretação Estatística de Dados , Modelos Estatísticos , Análise Multinível , Análise de Regressão , Humanos
12.
J Clin Child Adolesc Psychol ; 47(4): 581-594, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-27768384

RESUMO

The current study examined effects of a preventive intervention on patterns of change in symptoms of anxiety and depression in a sample of children of depressed parents. Parents with a history of depression (N = 180) and their children (N = 242; 50% female; Mage = 11.38; 74% Euro-American) enrolled in an intervention to prevent psychopathology in youth. Families were randomized to a family group cognitive behavioral intervention (FGCB) or a written information (WI) control condition. Parents and youth completed the Child Behavior Checklist and Youth Self Report at baseline, 6-, 12-, 18-, and 24-month follow up. Youth in the FGCB intervention reported significantly greater declines in symptoms of both anxiety and depression at 6, 12, and 18 months compared to youth in the WI condition. Youth with higher baseline levels of each symptom (e.g., anxiety) reported greater declines in the other symptom (e.g., depression) from 0 to 6 months in the FGCB intervention only. Changes in anxiety symptoms from 0 to 6 months predicted different patterns of subsequent changes in depressive symptoms from 6 to 12 months for the two conditions, such that declines in anxiety preceded and predicted greater declines in depression for FGCB youth but lesser increases in depression for WI youth. Findings inform transdiagnostic approaches to preventive interventions for at-risk youth, suggesting that both initial symptom levels and initial magnitude of change in symptoms are important to understand subsequent patterns of change in response to intervention.


Assuntos
Ansiedade/psicologia , Terapia Cognitivo-Comportamental/métodos , Depressão/psicologia , Pais/psicologia , Adolescente , Adulto , Criança , Filho de Pais com Deficiência/psicologia , Feminino , Humanos , Masculino , Fatores de Risco , Autorrelato
13.
Psychol Methods ; 22(1): 47-68, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27045852

RESUMO

Research interest often lies in comparing structural model specifications implying different relationships among latent factors. In this context parceling is commonly accepted, assuming the item-level measurement structure is well known and, conservatively, assuming items are unidimensional in the population. Under these assumptions, researchers compare competing structural models, each specified using the same parcel-level measurement model. However, little is known about consequences of parceling for model selection in this context-including whether and when model ranking could vary across alternative item-to-parcel allocations within-sample. This article first provides a theoretical framework that predicts the occurrence of parcel-allocation variability (PAV) in model selection index values and its consequences for PAV in ranking of competing structural models. These predictions are then investigated via simulation. We show that conditions known to manifest PAV in absolute fit of a single model may or may not manifest PAV in model ranking. Thus, one cannot assume that low PAV in absolute fit implies a lack of PAV in ranking, and vice versa. PAV in ranking is shown to occur under a variety of conditions, including large samples. To provide an empirically supported strategy for selecting a model when PAV in ranking exists, we draw on relationships between structural model rankings in parcel- versus item-solutions. This strategy employs the across-allocation modal ranking. We developed software tools for implementing this strategy in practice, and illustrate them with an example. Even if a researcher has substantive reason to prefer one particular allocation, investigating PAV in ranking within-sample still provides an informative sensitivity analysis. (PsycINFO Database Record


Assuntos
Interpretação Estatística de Dados , Modelos Estatísticos , Humanos , Software
14.
Prev Sci ; 18(1): 12-19, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27866307

RESUMO

Random coefficient-dependent (RCD) missingness is a non-ignorable mechanism through which missing data can arise in longitudinal designs. RCD, for which we cannot test, is a problematic form of missingness that occurs if subject-specific random effects correlate with propensity for missingness or dropout. Particularly when covariate missingness is a problem, investigators typically handle missing longitudinal data by using single-level multiple imputation procedures implemented with long-format data, which ignores within-person dependency entirely, or implemented with wide-format (i.e., multivariate) data, which ignores some aspects of within-person dependency. When either of these standard approaches to handling missing longitudinal data is used, RCD missingness leads to parameter bias and incorrect inference. We explain why multilevel multiple imputation (MMI) should alleviate bias induced by a RCD missing data mechanism under conditions that contribute to stronger determinacy of random coefficients. We evaluate our hypothesis with a simulation study. Three design factors are considered: intraclass correlation (ICC; ranging from .25 to .75), number of waves (ranging from 4 to 8), and percent of missing data (ranging from 20 to 50%). We find that MMI greatly outperforms the single-level wide-format (multivariate) method for imputation under a RCD mechanism. For the MMI analyses, bias was most alleviated when the ICC is high, there were more waves of data, and when there was less missing data. Practical recommendations for handling longitudinal missing data are suggested.


Assuntos
Viés , Interpretação Estatística de Dados , Estudos Longitudinais , Modelos Estatísticos , Projetos de Pesquisa
15.
Psychother Res ; 27(4): 425-436, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-26686878

RESUMO

OBJECTIVE: Individually-randomized psychotherapy trials are often partially nested. For instance, individuals assigned to a treatment arm may be clustered into therapy groups for purposes of treatment administration, whereas individuals assigned to a wait-list control are unclustered. The past several years have seen rapid expansion and investigation of methods for analyzing partially nested data. Yet partial nesting often remains ignored in psychotherapy trials. METHODS: This review integrates and disseminates developments in the analysis of partially nested data that are particularly relevant for psychotherapy researchers. RESULTS: First, we differentiate among alternative partially nested designs. Then, we present adaptations of multilevel model specifications that accommodate each design. Next, we address how moderation by treatment as well as mediation of the treatment effect can be investigated in partially nested designs. Model fitting results, annotated software syntax, and illustrative data sets are provided and key methodological issues are discussed. CONCLUSIONS: We emphasize that cluster-level variability in the treatment arm need not be considered a nuisance; it can be modeled to yield insights about the treatment process.


Assuntos
Modelos Estatísticos , Avaliação de Resultados em Cuidados de Saúde/métodos , Psicoterapia/métodos , Projetos de Pesquisa , Humanos
16.
Br J Math Stat Psychol ; 69(3): 316-343, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27458827

RESUMO

Multilevel data structures are common in the social sciences. Often, such nested data are analysed with multilevel models (MLMs) in which heterogeneity between clusters is modelled by continuously distributed random intercepts and/or slopes. Alternatively, the non-parametric multilevel regression mixture model (NPMM) can accommodate the same nested data structures through discrete latent class variation. The purpose of this article is to delineate analytic relationships between NPMM and MLM parameters that are useful for understanding the indirect interpretation of the NPMM as a non-parametric approximation of the MLM, with relaxed distributional assumptions. We define how seven standard and non-standard MLM specifications can be indirectly approximated by particular NPMM specifications. We provide formulas showing how the NPMM can serve as an approximation of the MLM in terms of intraclass correlation, random coefficient means and (co)variances, heteroscedasticity of residuals at level 1, and heteroscedasticity of residuals at level 2. Further, we discuss how these relationships can be useful in practice. The specific relationships are illustrated with simulated graphical demonstrations, and direct and indirect interpretations of NPMM classes are contrasted. We provide an R function to aid in implementing and visualizing an indirect interpretation of NPMM classes. An empirical example is presented and future directions are discussed.


Assuntos
Algoritmos , Interpretação Estatística de Dados , Modelos Estatísticos , Análise de Regressão , Estatísticas não Paramétricas , Simulação por Computador , Distribuições Estatísticas , Estatística como Assunto
17.
Multivariate Behav Res ; 51(2-3): 296-313, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27054282

RESUMO

Item parceling remains widely used under conditions that can lead to parcel-allocation variability in results. Hence, researchers may be interested in quantifying and accounting for parcel-allocation variability within sample. To do so in practice, three key issues need to be addressed. First, how can we combine sources of uncertainty arising from sampling variability and parcel-allocation variability when drawing inferences about parameters in structural equation models? Second, on what basis can we choose the number of repeated item-to-parcel allocations within sample? Third, how can we diagnose and report proportions of total variability per estimate arising due to parcel-allocation variability versus sampling variability? This article addresses these three methodological issues. Developments are illustrated using simulated and empirical examples, and software for implementing them is provided.


Assuntos
Interpretação Estatística de Dados , Modelos Estatísticos , Incerteza , Algoritmos , Antecipação Psicológica , Humanos , Método de Monte Carlo , Autoimagem , Isolamento Social , Software , Estudantes/psicologia , Fatores de Tempo , Universidades
18.
J Clin Child Adolesc Psychol ; 45(2): 167-75, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-25491166

RESUMO

Clinical psychology researchers studying adolescents and young adults long have been interested in characterizing the latent categorical (classes/profiles) versus continuous (factors) nature of psychological syndromes. To inform this debate, researchers sometimes compare the fit of finite mixture versus factor analysis models to symptom data. This study explains and evaluates how missing data handling methods can impact results of this important model fit comparison. Via simulation, we assess three missing data-handling methods previously recommended to researchers fitting these models: multiple imputation using a saturated multivariate normal imputation model, multiple imputation using a hypothesized model, or full information maximum likelihood using the EM algorithm (FIML-EM). Results show that, under certain conditions, the method used to handle missing data can interfere with clinical psychologists' ability to accurately discriminate latent classes from continua. For instance, certain imputation methods increase the chance of selecting latent continua when latent classes truly exist. FIML-EM performed best overall. Recommendations for practice are discussed.


Assuntos
Análise Fatorial , Modelos Psicológicos , Algoritmos , Feminino , Humanos , Masculino
19.
Psychometrika ; 81(2): 506-34, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-25697371

RESUMO

Psychologists often use latent transition analysis (LTA) to investigate state-to-state change in discrete latent constructs involving delinquent or risky behaviors. In this setting, latent-state-dependent nonignorable missingness is a potential concern. For some longitudinal models (e.g., growth models), a large literature has addressed extensions to accommodate nonignorable missingness. In contrast, little research has addressed how to extend the LTA to accommodate nonignorable missingness. Here we present a shared parameter LTA that can reduce bias due to latent-state-dependent nonignorable missingness: a parallel-process missing-not-at-random (MNAR-PP) LTA. The MNAR-PP LTA allows outcome process parameters to be interpreted as in the conventional LTA, which facilitates sensitivity analyses assessing changes in estimates between LTA and MNAR-PP LTA. In a sensitivity analysis for our empirical example, previous and current membership in high-delinquency states predicted adolescents' membership in missingness states that had high nonresponse probabilities for some or all items. A conventional LTA overestimated the proportion of adolescents ending up in a low-delinquency state, compared to an MNAR-PP LTA.


Assuntos
Delinquência Juvenil , Modelos Estatísticos , Assunção de Riscos , Estatística como Assunto , Adolescente , Humanos , Probabilidade , Psicometria , Adulto Jovem
20.
J Abnorm Psychol ; 123(2): 336-49, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24886008

RESUMO

Prior research has shown cognitive reactivity to be a diathesis for depression. Seeking evidence for the developmental origins of such diatheses, the current study examined peer victimization and harsh parenting as developmental correlates of cognitive reactivity in 571 children and adolescents (ages 8-13 years). Four major findings emerged. First, a new method for assessing cognitive reactivity in children and adolescents showed significant reliability and demonstrated construct validity vis-à-vis its relation to depression. Second, history of more severe peer victimization was significantly related to cognitive reactivity, with verbal victimization being more strongly tied to cognitive reactivity than other subtypes of peer victimization. Third, harsh parenting was also significantly related to cognitive reactivity. Fourth, both peer victimization and harsh parenting made unique statistical contributions to cognitive reactivity, after controlling for the effects of the other. Taken together, these findings provide preliminary support for a developmental model pertaining to origins of cognitive reactivity in children and adolescents.


Assuntos
Bullying/psicologia , Vítimas de Crime/psicologia , Depressão/psicologia , Poder Familiar/psicologia , Grupo Associado , Adolescente , Criança , Depressão/etiologia , Suscetibilidade a Doenças , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes
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