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PubMed1994

Empirical tests of an information-motivation-behavioral skills model of AIDS-preventive behavior with gay men and heterosexual university students.

This article contains empirical tests of the information-motivation-behavioral skills (IMB) model of AIDS-preventive behavior (J.D. Fisher & Fisher, 1992; W.A. Fisher & Fisher, 1993a), which has been designed to understand and predict the practice of AIDS-preventive acts. The IMB model holds that AIDS-preventive behavior is a function of individuals' information about AIDS prevention, motivation to engage in AIDS prevention, and behavioral skills for performing the specific acts involved in prevention. The model further assumes that AIDS-prevention information and motivation generally work through AIDS-prevention behavioral skills to influence the initiation and maintenance of AIDS-preventive behavior. Supportive tests of the model, using structural equation modeling techniques, are reported with populations of gay male affinity group members (n = 91) and heterosexual university students (n = 174).

Acquired Immunodeficiency Syndrome↗

PubMed2002

Why do we punish? Deterrence and just deserts as motives for punishment.

One popular justification for punishment is the just deserts rationale: A person deserves punishment proportionate to the moral wrong committed. A competing justification is the deterrence rationale: Punishing an offender reduces the frequency and likelihood of future offenses. The authors examined the motivation underlying laypeople's use of punishment for prototypical wrongs. Study 1 (N = 336) revealed high sensitivity to factors uniquely associated with the just deserts perspective (e.g., offense seriousness, moral trespass) and insensitivity to factors associated with deterrence (e.g., likelihood of detection, offense frequency). Study 2 (N = 329) confirmed the proposed model through structural equation modeling (SEM). Study 3 (N = 351) revealed that despite strongly stated preferences for deterrence theory, individual sentencing decisions seemed driven exclusively by just deserts concerns.

Adult↗

PubMed1992

Changing AIDS-risk behavior.

This article contains a comprehensive, critical review of the acquired immunodeficiency syndrome (AIDS)-risk-reduction literature on interventions that have targeted risky sexual behavior and intravenous drug use practices. A conceptually based, highly generalizable model for promoting and evaluating AIDS-risk behavior change in any population of interest is then proposed. The model holds that AIDS-risk reduction is a function of people's information about AIDS transmission and prevention, their motivation to reduce AIDS risk, and their behavioral skills for performing the specific acts involved in risk reduction. Supportive tests of this model, using structural equation modeling techniques, are then reported for populations of university students and gay male affinity group members.

Acquired Immunodeficiency Syndrome↗

PubMed1988

A structural model approach toward the development of a theory of the link between stress and mental health.

This study attempts to develop an empirical model of the link between stress and mental health, focusing particularly on occupational stress. Three different models were assessed-the person-stress model, the dispositional model, and the indigenous model--using structural equation modelling. The indigenous model was found to be the most predictive of mental health. In this model, personality and coping strategies precede and determine the perception of job stressors, which ultimately affect the mental well-being of the individual.

Adaptation, Psychological↗

PubMed1999

Calculating the interindividual geometric standard deviation for use in the integrated exposure uptake biokinetic model for lead in children.

The integrated exposure uptake biokinetic (IEUBK) model, recommended for use by the U.S. Environmental Protection Agency at residential Superfund sites to predict potential risks to children from lead exposure and to establish lead remediation levels, requires an interindividual geometric standard deviation (GSDi) as an essential input parameter. The GSDi quantifies the variability of blood lead concentrations for children exposed to similar environmental concentrations of lead. Estimates of potential risks are directly related to the GSDi, and therefore the GSDi directly impacts the scope of remediation at Superfund sites. Site-specific GSDi can be calculated for sites where blood lead and environmental lead have been measured. This paper uses data from blood and environmental lead studies conducted at the Bingham Creek and Sandy, Utah, Superfund sites to calculate GSDi using regression modeling, box modeling, and structural equation modeling. GSDis were calculated using various methods for treating values below the analytical method detection and quantitation limits. Treatment of nonquantifiable blood lead concentrations affected the GSDi more than the statistical method used to calculate the GSDi. For any given treatment, the different statistical methods produced similar GSDis. Because of the uncertainties associated with data in the blood lead studies, we recommend that a range of GSDis be used when analyzing site-specific risks associated with exposure to environmental lead instead of a single estimate. Because the different statistical methods produce similar GSDis, we recommend a simple procedure to calculate site-specific GSDi from a scientifically sound blood and environmental lead study.

Algorithms↗

PubMed1999

Modeling computer interest in older adults: the role of age, education, computer knowledge, and computer anxiety.

We proposed a mediation model to examine the effects of age, education, computer knowledge, and computer anxiety on computer interest in older adults. We hypothesized that computer knowledge and computer anxiety would fully mediate the effects of age and education on computer interest. A sample of 330 older adults from local senior-citizen apartment buildings completed a survey that included an assessment of the constructs included in the model. Using structural equation modeling, we found that the results supported the hypothesized mediation model. In particular, the effect of computer knowledge operated on computer interest through computer anxiety. The effect of age was not fully mitigated by the other model variables, indicating the need for future research that identifies and models other correlates of age and computer interest. The most immediate application of this research is the finding that a simple 3-item instrument can be used to assess computer interest in older populations. This will help professionals plan and implement computer services in public-access settings for older adults. An additional application of this research is the information it provides for training program designers.

Age Factors↗

PubMed1994

Relationship of financial strain and psychosocial resources to alcohol use and abuse: the mediating role of negative affect and drinking motives.

Limited research has examined the relationship between financial strain and alcohol use and abuse. Building on affect regulation theory and recent research in the stress and alcohol literatures, this study developed and tested a model relating financial strain, social resources, personal resources, depression, and drinking to cope to alcohol use and abuse. Data were obtained from a random sample of 1,424 adults who indicated that they had drunk alcohol in the previous year. We tested and then revised our model using structural equation modeling analysis. Results supported the affect regulation model of financial strain and alcohol use and abuse. Generally, depression mediated the relationship between financial strain and drinking to cope, and drinking to cope mediated the relationship between depression and alcohol use and abuse. In addition, both gender and race moderated six of the relationships in our revised model.

Adult↗

PubMed2001

Tracking of physical fitness during adolescence: a panel study in boys.

PURPOSE: To investigate the tracking in physical fitness (PF) viewed as a whole, a multidimensional trait of the subject, and to establish the stability of each factor of PF in adolescence from the perspective of a panel study using the structural equation modeling approach. METHODS: From a sample of 454 boys followed from 12 to 18 yr of age of the Leuven Growth Study, we considered only three consecutive measurement occasions with a mean age of 12.76, 14.69, and 17.73 yr. Physical fitness was evaluated by means of a battery composed of the following tests: plate tapping, sit and reach, vertical jump, arm pull, leg lifts, bent arm hang, and shuttle run. Structural equation models were fitted to the data, namely autoregressive models with latent variables. These models were used to quantify the tracking of PF as a whole and also of the individual marker variables of fitness. RESULTS: Stability estimates of PF as a whole are rather high, beta21 = 0.86 and beta32 = 0.68, with an explained variance of 74% and 73%, respectively. Tracking coefficients represented by disattenuated autocorrelations among the fitness factor gave high results: r1,2 = 0.86; r1,3 = 0.78; and r2,3 = 0.85. CONCLUSIONS: Physical fitness as a whole is highly stable in adolescent years and very predictable from early years. The same is observed for each factor of fitness. Moreover, autoregressive models within the context of structural equation modeling are better suited than simple Pearson or Spearman autocorrelations to study the tracking problem of PF.

Adolescent↗

PubMed2001

IgE in unselected like-sexed monozygotic and dizygotic twins at birth and at 6 to 9 years of age: high but dissimilar genetic influence on IgE levels.

BACKGROUND: IgE is a major determinant of allergic disease. Twin analysis of serum levels of IgE has been carried out previously in children and adults with heritability estimates of 30% to 70% on the basis of ANOVA. OBJECTIVE: This study included the analysis of serum IgE in a population of 126 twins, 27 monozygotic pairs and 36 dizygotic pairs, studied at birth (cord blood [CB] IgE) and consecutively at the age of 6 to 9 years of age (serum IgE). METHODS: IgE was determined by means of RIA. ANOVA, correlation analysis, and structural equation modeling by maximal likelihood analysis was used for genetic analysis. RESULTS: Structural equation modeling by maximal likelihood analysis showed the best-fitting model to be the AE model (A for additive genetic variance and E for environmental variance) both at birth and later in childhood. The estimated heritability was 0.92 (95% CI, 0.84-0.95) for CB IgE and 0.78 (95% CI, 0.60-0.87) for serum IgE. The correlation between CB IgE and serum IgE was 0.04. CONCLUSIONS: The study demonstrated a higher genetic dependency of serum IgE than previously recognized. The low correlation between the IgE levels at birth and later in childhood suggested that different effector mechanisms may be operating at different ages.

Child↗

PubMed2002

Drug use and neurobehavioral, respiratory, and cognitive problems: precursors and mediators.

PURPOSE: To test a model of the early predictors and mediators of drug use and respiratory, neurobehavioral, and cognitive problems in adolescence and young adulthood. METHODS: We prospectively examined self-reported measures of unconventional behavior, peer- and self-drug use, and self-reported health problems in a sample of 286 males and 327 females. The sample represented the northeastern United States at the time the data were first collected in 1975. The participants were assessed in early, middle, and late adolescence and in young adulthood. Latent variable structural equation models were used to examine the data. RESULTS: Structural equation modeling conducted on the data provided support for the proposed longitudinal model. The findings indicated that adolescent drug use was associated indirectly with respiratory and directly with neurobehavioral and cognitive symptoms in young adulthood. Adolescent drug use during middle and late adolescence served as a mediator between unconventional behavior in early adolescence and health problems in young adulthood. CONCLUSIONS: A reduction in adolescent drug use may reduce respiratory and neurobehavioral and cognitive symptoms in young adulthood. This study identifies several points in the biopsychosocial pathways in adolescence leading to later health problems in young adulthood.

Adolescent↗

PubMed1998

Top-down, bottom-up, and horizontal models: the direction of causality in multidimensional, hierarchical self-concept models.

A new structural equation modeling approach to questions of the direction of causal flow between global and specific multidimensional measures of self-concept (SC) in two 2-wave, longitudinal studies demonstrated that (a) higher order factors were unable to explain relations among first-order factors at Time 1 (T1), at Time 2 (T2), or between T1 and T2; (b) T1 global SC had little effect on specific SC factors at T2 (a top-down model), but specific factors at T1 had even less effect on T2 global SC (a bottom-up model); and (c) many specific factors were more stable than global factors, but higher order factors were most stable. Results provide little support for top-down, bottom-up, or reciprocal models, instead arguing for a horizontal model in which each T2 SC factor is primarily a function of the matching T1 SC. This casts further doubt on the usefulness of hierarchical representations of SC.

Achievement↗

PubMed1994

Overview of methodological issues in the study of chronic care populations.

The intent of the methodology section of this volume was to provide an overview of recent thinking about analytic techniques that can be used to study chronic care populations, particularly dementia SCUs. As discussed earlier in this article, although not unique to these populations, longitudinal analysis of chronic care populations frequently involves several problems: nonequivalent comparison groups, unbalanced designs, censoring and attrition, autocorrelation (correlated repeated measures) and heterogeneous correlations across repeated measures. The last 5 years has witnessed considerable change and growth in the development of longitudinal modelling methodologies. Although developments in modelling cut across disciplines, there has been a focus on certain types of methods in several fields of applied statistics: psychometrics (e.g., analysis of change, item response theory, Rasch modelling of binary outcomes), mathematical sociology (e.g., structural equation modelling), demography (e.g., transition modelling), epidemiology (e.g., risk modelling), and biostatistics (e.g., examination of intervention effects using marginal and random effects modelling of repeated measures). An important issue is the interrelationship between measurement and outcome assessment. Source of measurement error must be considered (see Zimmerman and Magaziner in this volume), as must bias in assessments (see Teresi and Golden in this volume). While it has long been known that poor measurement can attenuate and bias estimates of longitudinal effects, the answer is not to attempt artificial solutions through use of corrections for attenuation (unreliability). Design and sampling issues are also critical to the correct conduct of any longitudinal study. Otherwise, estimates of prevalence, incidence, and intervention effects will be in error (see Beckett and Evans, in this volume). Several modelling approaches have been reviewed. Different points of view regarding change analysis have been presented; controversy remains regarding the "best" methods for examining change (see the commentary by Rogosa in this volume). Theory building using methods such as structural equation modelling remains a staple of longitudinal analysis, although several caveats have been discussed. New or revisited methodologies (random effects modelling, of which growth curve analysis can be viewed as a special case and event history modelling) offer promise in dealing with the knotty problems inherent in the longitudinal study of chronic care populations, namely, censoring, attrition, and unbalanced designs resulting in missing data (see the commentary by Nesselroade, in this issue). However, it remains clear that no one model or approach will be optimal for all applications.

Activities of Daily Living↗

PubMed2003

The potential synergy between cognitive models and modern psychometric models.

Analyses of cognitive aspects of survey methodology (CASM) and psychometric analysis are two methods that are able to complement each other. We use concrete examples to illustrate how psychometric analyses can test hypotheses from CASM. The psychometrics framework recognizes that survey responses are affected by other factors than the concept being assessed, for example by cognitive factors and processes. Such factors are subsumed under the concept of measurement error. Possible sources of measurement error can be tested, e.g. by randomized experiments. A standard way to reduce measurement error is to ask several questions about the same concept and combine the answers into a multi-item scale that is more precise than the individual items. Techniques like structural equation models use the item correlations to assess the magnitude of measurement error and to test the assumptions behind the multi-item scale, e.g. the effect of common response choices and item time frames. A central problem in modern psychometrics is how to model the mapping of the continuous latent variable onto the item response choice categories. This is achieved by threshold models (e.g. item response models and structural equation models for categorical data). These models can, for example, analyze the impact of mode of administration, test whether the items function in the same way for all people (measurement invariance/differential item functioning) and examine the consistency of responses from any single person. Such analyses provide new possibilities for combining psychometrics and cognitive methods.

Attitude to Health↗

PubMed2000

The SF-36 summary scales: problems and solutions.

To determine the accuracy of the SF-36 summary mental and physical health scales in reflecting their underlying subscales using the traditional method of scoring based on factor coefficients derived through principle components analysis and orthogonal rotation. A representative Australian population survey containing the SF-36 was used to obtain factor coefficients from principle components analysis and orthogonal rotation for scoring the physical component summary (PCS) and the mental component summary (MCS) of the SF-36 in the traditional way. In addition two other methods were used to produce coefficients. The first method used maximum likelihood extraction and oblique rotation. The second method fit a structural equation model to the data in a confirmatory factor analysis. The coefficients derived by each of the methods were applied to the data of a second representative population survey. This survey also provided data on physical and mental health status which allowed comparison of the summary scores and underlying subscales according to various health states. Neither of the scoring methods based on the exploratory factor analyses methods (orthogonal and oblique) produced summary scale scores, by age group, that adequately reflected the underlying subscales. When coefficients derived using structural equation modeling were fit to the data in a confirmatory factor analysis the MCS and PCS accurately reflected their underlying subscale scores. They also produced MCS and PCS scores for the various health states as would be expected from the underlying subscales. The traditional methods of scoring the SF-36 summary scales produce results that would not be expected from the underlying subscales. The problem was only corrected by fitting a structural equation model to the data in a confirmatory factor analysis. The results advise caution in the use of the SF-36 summary scales and suggests that alternative methods of developing factor coefficients need to be employed in studies using the SF-36 summary scales.

Adolescent↗

PubMed1994

Network interactions among limbic cortices, basal forebrain, and cerebellum differentiate a tone conditioned as a Pavlovian excitor or inhibitor: fluorodeoxyglucose mapping and covariance structural modeling.

1. The objective was to examine how opposite learned behavioral responses to the same physical tone were differentiated by the pattern of interactions between extraauditory neural regions. This was pursued using a new approach combining behavior, neuroimaging, and network analysis to integrate information about differences in regional activity with differences in the covariance relationships between brain areas. 2. A tone was used as either a Pavlovian conditioned excitor or inhibitor. Rats were conditioned with reinforced trials of a conditioned excitor (A+) intermixed with nonreinforced trials of a tone-light compound (AX-). The tone was the excitor (A+) for the tone-excitor group and was the inhibitor (X-) for the tone-inhibitor group. After conditioning, all rats were injected with [14C(U)]2-fluoro-2-deoxyglucose (FDG) and presented with the same tone. 3. FDG autoradiography was used to measure regional activity and to generate interregional correlations of activity resulting from the presentation of the tone. A stepwise discriminant analysis was used to select brain regions that differentiated the excitor from the inhibitor effects. 4. Network analysis consisted of constructing an anatomic model of the brain regions, selected by the discriminant analysis, linking the regions with their known anatomical connections. Then, functional models for the tone-excitor and -inhibitor groups were constructed using structural equation modeling. Correlations of activity between regions were decomposed to calculate numerical weights, or path coefficients, for each anatomic path. These path coefficients were used to compare the interactions for the tone-excitor and -inhibitor models. 5. Regional differences in FDG uptake were found in the sulcal frontal cortex (SFC), lateral septum (LS), medial septum/diagonal band (MS/DB), retrosplenial cortex (RS), and dentate-interpositus nuclei of the cerebellum (DEN). Discriminant analysis selected three other regions that significantly discriminated the tone-excitor and -inhibitor groups: perirhinal cortex (PRh), nucleus accumbens (ACB), and the anteroventral nucleus of the thalamus (AVN). 6. Structural equation modeling identified two functional circuits that differentiated the groups. One involved the basal forebrain regions (LS, MS/DB, ACB) and the other limbic thalamocortical structures (SFC, RS, PRh, AVN). Differences in the interactions within these circuits were mainly in sign of the covariance relationships between regions, from positive for the tone-excitor model to negative path coefficients for the tone-inhibitor model. The path coefficient between the basal forebrain circuit and the limbic thalamocortical circuit showed the largest magnitude difference. This quantitative difference was mediated by a path from the MS/DB to PRh.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2000

Evaluation of a model of attention with confirmatory factor analysis.

Structural equation modeling (specifically, analysis of moment structures; J. L. Arbuckle, 1996) was used to evaluate the goodness of fit of a model of components of attention (A. F. Mirsky, B. J. Anthony, C. C. Duncan, M. B. Aheam, & S. G. Kellam, 1991) to neuropsychological test data from 2 samples. One sample consisted of psychiatrically normal persons with and without sleep-disordered breathing, and the other sample consisted of the adults studied by A. F. Mirsky et al. (1991), who gave rise to this model. That sample included psychiatric patients as well as normals. An exploratory data reduction procedure, principal-components analysis, suggested that attention might be conceptualized as composed of 4 independent elements or components: focus-execute, sustain, shift, and encode. Neither the proposed orthogonal model nor a model permitting correlated factors adequately fit either data set, suggesting that these 4 attention constructs are as yet not clearly validated in the measures used to assess them.

Adult↗

PubMed1995

Migraine and concomitant symptoms among 8167 adult twin pairs.

We studied the inheritance of migraine and concomitant symptoms among 2690 monozygotic (1524 female and 1166 male) pairs and 5497 dizygotic (2951 female and 2546 male) twin pairs. Our material consists of a population-based questionnaire study among Finnish twins in 1981. The definition of migraine is based on a questionnaire method. Concordance was assessed using probandwise concordance rates and tetrachoric correlations for monozygotic (MZ) and dizygotic (DZ) twin pairs. For estimating the contribution of genetic factors to the susceptibility of migraine, a polygenic multifactorial model was used. Structural equation models were applied for estimating variance components and to compare different genetic models. Nearly one-half (40% to 50%) of the liability to migraine is attributable to genetic factors. In all structural analyses, the model with both additive genetic and unshared environmental component had the best goodness-of-fit value. The genetic component varied between 34% to 51% in different migraine types. There were no remarkable differences between sexes except in the effects due to dominance, where the proportion was 26% for men and 14% for women. Concomitant symptoms among subjects within pairs concordant for headache had genetic effects varying from 56% (subjects with unilaterality) and 56% (subjects with visual symptoms) to 45% (persons with nausea and vomiting). The two threshold model of headache points to the continuum model of headache, and the thresholds represent different levels of severity of the pain. Our results emphasize a multifactorial and higher than previously reported genetic pattern in the etiology of migraine. Also unshared environmental factors play an important role.

Diseases in Twins↗

PubMed2003

Family harmony as a protective factor against adolescent tobacco and alcohol use in Wuhan, China.

PURPOSE: To investigate the association between family harmony (FH) and tobacco and alcohol use (TAU) in Chinese adolescents. METHODS: Participants completed a survey in 1998 as part of a larger study of adolescent health in Wuhan, China. Analyses were performed on subjects for whom complete data were available (n = 183; 50.8% male; mean age = 13.17 yrs, std dev = 0.59). Structural equation modeling was utilized to quantify the relationships between the FH, TAU, depression, and academic aptitude factors. RESULTS: The conceptualized structural equation model was found to have a good fit to the data (CFI = 0.995; chi2 = 39.57 df = 38; p = 40). FH was a significant predictor of TAU (beta = -0.42, p < 0.05) and was protective. FH' was also negatively related to depression (r = -0.24, p < 0.05) and positively related to academic achievement/aptitude (r = 0.35, p < 0.05). CONCLUSIONS: These central findings highlight the value and importance placed on FH within the Chinese culture. Future prevention programs may benefit by taking into account FH as a potential mediator of TAU in adolescents in China.

Achievement↗