Thesis supervisor: David B. Watson. Includes bibliographical references (p. 175-181).

abstract: Although the issue of factorial invariance has received increasing attention in the literature, the focus is typically on differences in factor structure across groups that are directly observed, such as those denoted by sex or ethnicity. While establishing factorial invariance across observed groups is a requisite step in making meaningful cross-group comparisons, failure to attend to possible sources of latent class heterogeneity in the form of class-based differences in factor structure has the potential to compromise conclusions with respect to observed groups and may result in misguided attempts at instrument development and theory refinement. The present studies examined the sensitivity of two widely used confirmatory factor analytic model fit indices, the chi-square test of model fit and RMSEA, to latent class differences in factor structure. Two primary questions were addressed. The first of these concerned the impact of latent class differences in factor loadings with respect to model fit in a single sample reflecting a mixture of classes. The second question concerned the impact of latent class differences in configural structure on tests of factorial invariance across observed groups. The results suggest that both indices are highly insensitive to class-based differences in factor loadings. Across sample size conditions, models with medium (0.2) sized loading differences were rejected by the chi-square test of model fit at rates just slightly higher than the nominal .05 rate of rejection that would be expected under a true null hypothesis. While rates of rejection increased somewhat when the magnitude of loading difference increased, even the largest sample size with equal class representation and the most extreme violations of loading invariance only had rejection rates of approximately 60%. RMSEA was also insensitive to class-based differences in factor loadings, with mean values across conditions suggesting a degree of fit that would generally be regarded as exceptionally good in practice. In contrast, both indices were sensitive to class-based differences in configural structure in the context of a multiple group analysis in which each observed group was a mixture of classes. However, preliminary evidence suggests that this sensitivity may contingent on the form of the cross-group model misspecification. / Dissertation/Thesis / Ph.D. Psychology 2011

In general, scholars agree that there are several contextual factors influencing immigrants in the UK to use alcohol and other drugs. Not much is known however about how and to what extend acculturative changes are influencing substance use in immigrants and members of minority ethnic groups. This study aims to develop a better understanding of the predictors of substance use by exploring the impact that acculturative changes have in patterns of substance use amongst Brazilian immigrants in the UK. A combination of quantitative and qualitative methods was adopted in a cross-national research sample compromised of Brazilian participants residing in the UK (n=164) and Brazilian participants residing in Brazil (n=161). Initially, quantitative analysis was carried out to explore country differences in types, frequency, and predictors of substance use. The quantitative analysis was followed by qualitative data collection to explore in-depth complex issues related to social and cultural factors that underlie the susceptibility of Brazilian immigrants to use alcohol and other drugs. Thematic Analysis was adopted to analyse the qualitative data. It was observed that Brazilians who had immigrated to the UK showed an overall increase in the frequency with which they used substances, however, significant differences were only found in recreational drug use, poly-substance use, and binge drinking. Such shifts were influenced by attitudes, values, and behavioural changes, and were strongly predicted by the stress caused by threat to cultural identity. Both drinking for social motives and gender differences predicted involvement in substance use in Brazilians in the UK and in Brazil, whereas resilience, impulsivity, positive and negative affect, and reasons for drinking motivated by conformity and coping where found to have no effect on patterns of substance use in either of the samples. Overall, it seems that, whilst Brazilians in the UK are motivated by negative reinforcement processes to use substances (e.g. coping), in Brazil participants are motivated by positive reinforcement processes (e.g. enhancement). High contact with both British and Brazilian cultures will only predict substance use when threat to cultural identity moderates this relationship. Brazilian immigrants new to the UK are at greater risk for substance use independent of any acculturative strategies or stresses. Length of residence in the UK does not predict the adoption of integration strategies and the stresses caused by acculturation can be experienced throughout the life course of the Brazilian immigrants in the UK.

Magister Artium (Psychology) - MA(Psych) / Globally the Subjective Well-Being (SWB) of children is recognized as having a significant effect on the child's psychological and social functioning. Furthermore, not only does children's SWB have effects on childhood well-being research, it has also increased the knowledge of how children view their life that has been determined through the measurement of specific domains that relates to children's lives. The overall aim of this study was to ascertain the SWB of children across three age groups in the Western Cape. Within this process, the study further aimed to fit the structural model depicting the nature of the relationship between global, domain specific and overall life satisfaction across three age groups. The Theory of Model Fit: Goodness of Fit and Fit Indexes was used as the theoretical position conceptualising the study. The sample included 3236 children aged 8, 10, and 12 years selected using stratified random sampling from 29 schools in the Western Cape. The study used Structural Equation Modelling and Multi-group Confirmatory Factor Analysis to address the stated aims and objectives. Ethics principles of informed consent, anonymity, the right to withdraw and privacy were adhered to within the study. Findings of this study indicate that the descriptive statistics depicted high levels of SWB for both measures with mean composite scores ranging between 81.20 to 86.15 for the SLSS; and 83.29 to 84.07 for the PWI-SC. Confirmatory factor analysis showed excellent fit for both the SLSS and the PWI-SC across age groups (multi-group model). The application of Multi-group Confirmatory Factor Analysis in the current study found the measures to be comparable across the three age groups (8, 10 & 12) for the SLSS and two age groups for the PWI-SC (10 & 12). A combined model with two latent constructs, representing different levels of abstraction was also tested. An excellent fit was obtained for this combined model. Appropriate fit statistics was obtained for the overall pooled sample. The standardised regression weights of 0.57 for the PWI-SC and 0.47 for the SLSS point to adequate loadings of the latent constructs onto the OLS. Markedly, it was found that a significant overall mean difference was found between the 10 and 12-year olds and not between the 8 and 10-year olds; while for the domain-specific PWI-SC a similar tendency was noted across the 10 and 12-year olds participants (8 year old group was not applicable in this analysis). / National Research Foundation (NRF)

Objective: This work consisted of three research projects bridged by their focus on a multivariate assessment of executive functions in research and practice: (a) a systematic review and re-analysis of latent variable studies on executive function test batteries, (b) a confirmatory factor analysis (CFA) of the Delis-Kaplan Executive Function System (D-KEFS), the most commonly administered executive function test battery in clinical practice, and (c) the derivation of multivariate base rates for the D-KEFS, offering a psychometric resource with direct applications to clinical practice. Method: Systematic review. The systematic review identified 45 eligible samples (N=9,498 participants, mean age range: 3.01-74.40 years-old) and 21 correlation matrices eligible for re-analysis, comparing seven competing models including the most commonly evaluated factors: updating/working memory, inhibition, and shifting. Model results were summarized based on the mean percent accepted (i.e., mean rate at which models both properly converged and met fit thresholds: CFI≥.90/RMSEA≤.08). CFA. Using adults from the D-KEFS normative sample (N=425; 20-49 years-old), eight alternative measurement models were evaluated for a subset of D-KEFS tests. Factors from the accepted measurement model predicted three tests measuring constructs less often evaluated in the executive function literature: abstraction, reasoning, and problem solving. Base rates. The frequency of low scores occurring among the D-KEFS normative sample (N=1,050; 16-89 years-old) was calculated for the full D-KEFS and two brief batteries using stratifications for age, education, and intelligence. Results: Systematic review. The most often accepted models varied by age (preschool=one/two-factor; school-age=two/three-factor; adolescent/adult=three/nested-factor; older adult=two/three-factor), and most frequently included updating/working memory, inhibition, and shifting factors. The nested-factor and three-factor models were accepted most often and at similar rates among adult samples: 33-34% and 25-32%, respectively. No model was accepted most often for child/adolescent samples, but those with shifting differentiated garnered less support. CFA. A three-factor model including inhibition, shifting, and fluency fit the data well (CFI=0.938; RMSEA=0.047), although a two-factor model merging shifting/fluency fit similarly well (CFI=0.929; RMSEA=0.048). A bifactor model fit best (CFI=0.977; RMSEA=0.032), but rarely converged. Shifting best predicted tests of reasoning, abstraction, and problem solving (p<0.05; R2=0.246-0.408). Base rates. Low scores, based on commonly used clinical cutoffs, occurred frequently among healthy adults. For a three-test, four-test, and full D-KEFS battery, 62.8%, 71.8%, and 82.6% obtained ≥1 score(s) ≤16th percentile, respectively, and 36.1%, 42.0%, 50.7%, obtained ≥1 score(s) ≤5th percentile, respectively. The frequency of low scores increased with lower intelligence and fewer years of education. Discussion: The systematic review effort did not identify a definitive model of executive functions for either adults or children/adolescents, demonstrating the continued need to re-evaluate the conceptualization and measurement of this construct in future research. The D-KEFS CFA offers some evidence of clinical measures capturing theoretical constructs, but is not directly translatable into clinical practice; while the multivariate base rates are useful to clinicians, but do not bridge theory and assessment. This research reaffirms the elusive nature of executive functions in both research and clinical spheres, and represents a step forward in an enduring scientific process towards a true understanding of this mysterious construct. / Graduate / 2018-07-24

Magister Artium - MA / Recent advancements in child well-being research have shown an increased interest in the importance of subjective well-being. The development of instruments and scales to measure subjective well-being among children and adolescents is in its infancy. Furthermore, there are few existing cross-cultural studies with child and adolescent populations. Validation of existing measures and cross-cultural comparisons has been identified by a number of researchers as critical in contributing to the international dialogue. In the current study, two measures of subjective well-being (Student Life Satisfaction Scale and Personal Well-Being Index-School Children) are tested among a sample of children in the Western Cape region of South Africa. Noting the diversity of experience between children from different socio-economic status groups in South Africa, the study further aims to determine the extent to which the measures are comparable across socio-economic status groups. Data from the Children’s World Survey were used; and includes a sample of 1004 children randomly selected from 15 schools within the Cape Town Metropole. Confirmatory factor analysis was used to test the overall fit structure and multi-group factor analysis, with Scalar and Metric invariance constraints. The results show appropriate fit structure for the overall model, with Scalar and Metric factor invariance tenable across socio-economic status groups. The overall findings suggest that the two measures are appropriate for use with children from low and medium socio-economic status groups in the Western Cape province of South Africa.

Objective: Executive functions govern our ability to navigate complex and novel situations in day-to-day life. There is increased interest on environmental influences that may cause changes to executive functioning. The current thesis involves two studies examining the derivation and performance of an executive behaviour screener from the Behavioral Assessment System for Children (BASC-2-PRS; Reynolds & Kamphaus, 2004) on two different adolescent samples using a previously derived four-factor model of executive functioning (Garcia-Barrera et al., 2011, 2013). Participants and Methods: Study 1. BASC-2 PRS standardization data consisting of a demographically matched American sample of 2722 12-21 year olds was obtained. The screener was derived using 25 items assigned a priori to each executive factor. Confirmatory factor analysis (CFA), invariance testing, and multiple indicators multiple causes (MIMIC) models were used to evaluate the screener. Study 2. The screener was applied to a previously collected sample of 479 elite adolescent hockey players from Canada with or without a history of concussion, followed through a single season of play. CFA, invariance testing, and MIMIC models were used to evaluate the screener and the hockey sample was compared to the standardization sample. Results: Study 1. Acceptable-to-good reliability was obtained for all factors (α = .75-.89). The four-factor model was the best fit to the data (CFI = .990, TLI = .989, RMSEA = .037). Configural, metric, and scalar but not latent mean invariance was shown for sex. Age-related uniform differential item functioning (DIF) and SES-related uniform and non-uniform DIF were shown. Standardized norms for use in clinical settings were created. Study 2. Acceptable-to-good reliability was shown for 3 factors (α = .72-.85). Emotional Control showed poor reliability (α = .58). The four-factor model was the best fit to the data (CFI = .991, TLI = .990, RMSEA = .026). Configural, metric, and scalar but not latent mean invariance was shown between the two samples. Uniform and non-uniform DIF were not observed for those with an increasing number of past concussions. Conclusions: Findings support the four-factor model measured through the screener in adolescence. Females and hockey players demonstrate fewer executive behaviour problems overall. Sex, age, and SES may influence the interpretation of factor scores. Continued exploration and development of the screener is suggested. / Graduate / 2018-09-27

The Santa Clara Brief Compassion Scale (SCBCS) is a brief measure of compassion, created in English and translated into Brazilian Portuguese. Nonetheless, to date, no study has assessed the psychometric evidence of its Spanish translation. This study examines the evidence of validity, reliability, and factorial invariance according to the gender of a Spanish version of the SCBCS. Participants included 273 Peruvian university students (50.9% women) with an average age of 21.23 years (SD = 3.24); divided into two groups of men and women to conduct the invariance factor analysis. Other measures of mindfulness, well-being, empathy, and anxiety were applied along with the SCBCS. The Confirmatory Factor Analysis (CFA) indicated that a unifactorial model adjusted significantly to the data (χ2 = 12,127, df = 5, p =.033, χ2 /df = 2.42, CFI =.998, RMSEA =.072 [CI90%.019,.125]; SRMR =.030, WRMR =.551) and presented good reliability (α =.90 [95%.88–.92]; ω =.91). Moreover, correlations between the SCBCS and other measures of mindfulness (r =.53, p <.05, cognitive empathy (r = 55; p <.05), affective empathy (r =.56, p <.05), well-being (r =.55, p <.05), and anxiety (r = −.46; p <.05) supported the convergent and discriminant validity. Likewise, the multiple-group CFA supported the factorial invariance according to the gender of the SCBCS. Results indicate that the SCBCS possesses evidence of validity, reliability, and invariance between men and women for measuring compassion toward others in Peruvian undergraduate students. SCBCS is expected to be used by researchers, healthcare professionals, teachers, and others as a useful measure of compassion in college students.

Safety interventions must be approached in a holistic manner, by taking cognisance of the organisational system in which accidents present themselves. Thus, a need to understand the individual in context of the organisational system that he/she functions in exists. This study focuses on the relationship between attitudes, beliefs, intention, perception, control and the propensity of employees to engage in unsafe behaviour, with a view towards improving safety statistics. In this regard the study investigated the construct validity of a Safety Survey instrument, based on the responses (n=450) of employees in the mining industry. An Exploratory Factor Analysis showed that the Safety Survey instrument differentiated between two to three underlying factors. The result of the Confirmatory Factor Analysis tested two models by demonstrating the minimum requirements of the goodness of fit indexes. The construct validity of the Safety Survey instrument could be established for two nested models that identified an internal and external locus of control factor. The statistical evidence indicated an acceptable model fit. The statistical evidence validated the construct validity of the measurement model. Copyright 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Windbacher, M 2008, Determining the construct validity of the safety survey instrument, MCom dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-02202012-123434 / > C12/4/66/gm / Dissertation (MCom)--University of Pretoria, 2008. / Human Resource Management / unrestricted

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