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The authors propose new procedures for evaluating direct, indirect, and total effects in multilevel models when all relevant variables are measured at Level 1 and all effects are random. Formulas are provided for the mean and variance of the indirect and total effects and for the sampling variances of the average indirect and total effects. Simulations show(More)
Growth mixture models are often used to determine if subgroups exist within the population that follow qualitatively distinct developmental trajectories. However, statistical theory developed for finite normal mixture models suggests that latent trajectory classes can be estimated even in the absence of population heterogeneity if the distribution of the(More)
Many important research hypotheses concern conditional relations in which the effect of one predictor varies with the value of another. Such relations are commonly evaluated as multiplicative interactions and can be tested in both fixed- and random-effects regression. Often, these interactive effects must be further probed to fully explicate the nature of(More)
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(More)
This paper contributes new evidence on the association between immigrant status and health by describing and attempting to explain patterns of co-occurring sex and drug use behaviors among Asian and Latino adolescents in the United States. Nine patterns of sex and drug use behaviors were identified from a cluster analysis of data from 3,924 Asian and Latino(More)
We examined the hypothesis that family, peer and neighborhood violence would moderate relations between heavy alcohol use and adolescent dating violence perpetration such that relations would be stronger for teens in violent contexts. Random coefficients growth models were used to examine the main and interaction effects of heavy alcohol use and four(More)
OBJECTIVES We used nationally representative data to examine whether individuals' sexual and drug behavior patterns account for racial disparities in sexually transmitted disease (STD) and HIV prevalence. METHODS Data were derived from wave III of the National Longitudinal Study of Adolescent Health. Participants were aged 18 to 26 years old; analyses(More)
BACKGROUND The notion that adolescents "self-medicate" depression with substance use and sexual behaviors is widespread, but the temporal ordering of depression and these risk behaviors is not clear. This study tests whether gender-specific patterns of substance use and sexual behavior precede and predict depression or vice versa. METHODS Data are from(More)
Finite mixture models are well known to have poorly behaved likelihood functions featuring singularities and multiple optima. Growth mixture models may suffer from fewer of these problems, potentially benefiting from the structure imposed on the estimated class means and covariances by the specified growth model. As demonstrated here, however, local(More)
AIMS To examine the prevalence and correlates of crystal methamphetamine use among young adults in the USA. DESIGN Cross-sectional analyses of nationally representative data of young adults from the National Longitudinal Study of Adolescent Health (Add Health). SETTING In-home interviews conducted in 2001-02. PARTICIPANTS A total of 14,322 respondents(More)