It is important that organisations are aware of factors that might affect the levels of well-being of employees, as employees are instrumental to the achievement of organisational goals. Well-being of employees can be conceptualised in terms of burnout and engagement. Studies have shown that different factors contribute to the employee experience of burnout and engagement. These factors include job demands and resources and psychological conditions (psychological meaningfulness, psychological availability and psychological safety). Although various studies regarding burnout and engagement can be found in literature, three research gaps have been identified from the studies. First, a reliable and valid instrument is needed to measure job demands and resources in a specific organisation. Second, given the cost of some measures of burnout, inadequacies in conceptualisation of the burnout construct and the inadequate psychometric properties of others, an inexpensive measure is needed which can be used to measure burnout in a valid and reliable way. Third, no studies seem to be found which focus on the effects of job demands and resources on burnout and engagement via specific psychological conditions (i.e. psychological meaningfulness, availability and safety). The general objective of this research therefore was to investigate the well-being of employees in a South African agricultural research organisation. It focused on job demands, job resources, burnout, work engagement and psychological conditions. The objective of the first study was to investigate the job demands and resources of employees in a South African agricultural research organisation. The study specifically examined the validity and reliability of a scale adapted to measure job demands and resources of the employees and established the prevalent job demands and resources of the employees. Differences that may exist based on the employees‟ demographic variables were also investigated. The aim of the second study was to provide an overview of current burnout measures that are used in the literature. From the literature, gaps were identified and used to develop a new Burnout Scale for use with employees within a South African agricultural research organisation. The research then examined the construct validity, reliability, construct equivalence and item bias of the newly-developed Burnout Scale. The research also investigated whether any differences in burnout existed in relation to the employees‟ demographic variables. The third study investigated the relationships between specific job demands, job resources, psychological conditions, burnout, and work engagement by testing a structural model of burnout and engagement in a sample of employees within a South African agricultural research organisation. The research method for each of the three articles consisted of a brief literature review and an empirical study. A non-probability availability sample of 443 agricultural employees was used. A cross-sectional design, with a survey as the data collection technique, was used. Measuring instruments that were utilised included an adapted Job Demands-Resources scale (AJDRS), a self-developed Burnout Scale (BS), a self-developed Work Engagement Scale (WES), an adapted Psychological Conditions Questionnaire (PCQ), and a biographical questionnaire. The statistical analyses were carried out with the help of the SPSS programme (IBM SPSS statistics, version 21) and MPLUS version 7.11 (Muthén, & Muthén 1998-2013). The statistical methods utilised in the three articles included descriptive statistics, Cronbach alpha coefficients, principal factor analysis, Pearson product-moment correlation coefficients, MANOVA, ANOVA, differential item functioning (DIF), and structural equation modelling. Evidence was established for the factorial validity and reliability of the AJDRS. The results indicate that the job demands experienced by employees in an agricultural research organisation are: overload and job insecurity; while job resources were: organisational support, growth opportunities, control, rewards, and physical resources (equipment). It was furthermore found that there were differences in the perceived job demands and resources of employees. In addition, the BS was found to consist of three reliable factors, i.e. fatigue, emotional exhaustion/withdrawal, and cognitive weariness. The results also showed construct equivalence for the Burnout construct, and no item bias for the language groups examined. Age was found to affect the level of perceived burnout of the employees. Furthermore, job resources (growth opportunities, control, and organisational support) were found to be positively associated with engagement, while lack of resources and job demands (overload) are positively associated with burnout of employees. Psychological meaningfulness, safety and availability are positively associated with work engagement, and negatively associated with burnout. The psychological conditions of availability, safety, and meaningfulness mediated the relationship between job resources and work engagement, as well as between lack of job resources and burnout. Psychological availability and meaningfulness mediated the relationship between job demands and burnout; however, the mediation effect of psychological safety on the relationship between job demands and burnout could not be established. Recommendations are made for practice, as well as future research. / PhD (Industrial Psychology), North-West University, Potchefstroom Campus, 2014

It is important that organisations are aware of factors that might affect the levels of well-being of employees, as employees are instrumental to the achievement of organisational goals. Well-being of employees can be conceptualised in terms of burnout and engagement. Studies have shown that different factors contribute to the employee experience of burnout and engagement. These factors include job demands and resources and psychological conditions (psychological meaningfulness, psychological availability and psychological safety). Although various studies regarding burnout and engagement can be found in literature, three research gaps have been identified from the studies. First, a reliable and valid instrument is needed to measure job demands and resources in a specific organisation. Second, given the cost of some measures of burnout, inadequacies in conceptualisation of the burnout construct and the inadequate psychometric properties of others, an inexpensive measure is needed which can be used to measure burnout in a valid and reliable way. Third, no studies seem to be found which focus on the effects of job demands and resources on burnout and engagement via specific psychological conditions (i.e. psychological meaningfulness, availability and safety). The general objective of this research therefore was to investigate the well-being of employees in a South African agricultural research organisation. It focused on job demands, job resources, burnout, work engagement and psychological conditions. The objective of the first study was to investigate the job demands and resources of employees in a South African agricultural research organisation. The study specifically examined the validity and reliability of a scale adapted to measure job demands and resources of the employees and established the prevalent job demands and resources of the employees. Differences that may exist based on the employees‟ demographic variables were also investigated. The aim of the second study was to provide an overview of current burnout measures that are used in the literature. From the literature, gaps were identified and used to develop a new Burnout Scale for use with employees within a South African agricultural research organisation. The research then examined the construct validity, reliability, construct equivalence and item bias of the newly-developed Burnout Scale. The research also investigated whether any differences in burnout existed in relation to the employees‟ demographic variables. The third study investigated the relationships between specific job demands, job resources, psychological conditions, burnout, and work engagement by testing a structural model of burnout and engagement in a sample of employees within a South African agricultural research organisation. The research method for each of the three articles consisted of a brief literature review and an empirical study. A non-probability availability sample of 443 agricultural employees was used. A cross-sectional design, with a survey as the data collection technique, was used. Measuring instruments that were utilised included an adapted Job Demands-Resources scale (AJDRS), a self-developed Burnout Scale (BS), a self-developed Work Engagement Scale (WES), an adapted Psychological Conditions Questionnaire (PCQ), and a biographical questionnaire. The statistical analyses were carried out with the help of the SPSS programme (IBM SPSS statistics, version 21) and MPLUS version 7.11 (Muthén, & Muthén 1998-2013). The statistical methods utilised in the three articles included descriptive statistics, Cronbach alpha coefficients, principal factor analysis, Pearson product-moment correlation coefficients, MANOVA, ANOVA, differential item functioning (DIF), and structural equation modelling. Evidence was established for the factorial validity and reliability of the AJDRS. The results indicate that the job demands experienced by employees in an agricultural research organisation are: overload and job insecurity; while job resources were: organisational support, growth opportunities, control, rewards, and physical resources (equipment). It was furthermore found that there were differences in the perceived job demands and resources of employees. In addition, the BS was found to consist of three reliable factors, i.e. fatigue, emotional exhaustion/withdrawal, and cognitive weariness. The results also showed construct equivalence for the Burnout construct, and no item bias for the language groups examined. Age was found to affect the level of perceived burnout of the employees. Furthermore, job resources (growth opportunities, control, and organisational support) were found to be positively associated with engagement, while lack of resources and job demands (overload) are positively associated with burnout of employees. Psychological meaningfulness, safety and availability are positively associated with work engagement, and negatively associated with burnout. The psychological conditions of availability, safety, and meaningfulness mediated the relationship between job resources and work engagement, as well as between lack of job resources and burnout. Psychological availability and meaningfulness mediated the relationship between job demands and burnout; however, the mediation effect of psychological safety on the relationship between job demands and burnout could not be established. Recommendations are made for practice, as well as future research. / PhD (Industrial Psychology), North-West University, Potchefstroom Campus, 2014

School physical science is a prerequisite for science courses at institutions of higher education. Science graduates are an important link in a nation's scientific and technological development which often shapes a country's economic development. The purpose of this study was to investigate psychological and social factors influencing physical science achievement and attitude of black secondary school students in South Africa. The first part of the literature study which was concerned with physical science education in South Africa revealed that few black students chose to study science after standard seven, that failure rates were high and that science education was generally in a state of crisis. The second part of the literature study identified psychological and social factors related to science achievement and attitude. These were home environment variables, teacher and school related variables, personal variables (self-concept, motivation, gender, ethnicity) and students' abilities. The third part was the construction of a Structural Equation Model (SEM) specifying the relationships among the psychological and social factors and their effects on physical science achievement and attitude. The theoretical SEM fit the data reasonably well. The best fitting model, however, was a revised model in which several paths were constrained. The latter accounted for a substantial variance in attitude towards physical science (70.3%) and a meagre 17.7% in physical science achievement. The variables ability, home environment and self-concept had the greatest total effects on physical science achievement. Self-concept, home environment and motivation made the greatest total contributions to physical science attitude. Teacher characteristics and school environment had non-significant effects on physical science achievement and attitude. Multiple-group structural equation modelling analyses found no significant difference in the structural parameters of boys and girls. Theoretical and educational implications of the findings were discussed and specific recommendations for improving educational practice in general and physical science achievement and attitude in particular, were made. / Psychology of Education / D. Ed. (Psychology of Education)

The purpose of the study was to identify and transform, as necessary, constructs of communication satisfaction and to develop a hybrid quantitative audit of organisational communication satisfaction for collectivist contexts that is both reliable and valid, using Amos Graphics for structural equation modelling. The objective was also to develop a full latent variable model and to test its fitness to the data collected from a random sample of civil servants across Addis Ababa’s civil service bureaus. The study comprised three sequential parts, namely pilot, exploratory factor analysis (EFA) (Main Study One) and confirmatory factor analysis (CFA) (Main Study Two). These were used as per the existing framework in instrument development and validation. The pilot study indicated the need for more robust data. After a series of tests, principal factor axis factoring with oblique rotation was used as the most appropriate for perceptual data, out of several options on the EFA menu. The initially hypothesised six-factor solution with the dimensions of horizontal communication, personal feedback, supervisory communication, communication climate, relational trust and job satisfaction was found to be unfit for the data on conceptual and statistical grounds and psychometric analyses which involved the use of eigenvalues and the scree plot. A more appropriate two-factor solution based on the more precise parallel analysis strategy was consistent with current research that communication satisfaction is best conceptualised in terms of informational and relational domains as operationalised using the EFA procedure. The two-factor solution led to the formation of a 17-item scale out of the original 30-item measure, with two latent dimensions namely relational satisfaction and informational satisfaction. The items of the new EFA-generated organisational communication satisfaction scale were renumbered consecutively and the scale was cross-validated on a xiv new sample of 288 civil servants from the Addis Ababa City Administration. The cross-validation necessitated model respecification and re-estimation. The respecified model underwent validation at different levels. All seven aspects of validity, namely content validity, construct validity, factorial validity, reliability, convergent validity, discriminant validity and nomological validity, were addressed and found to be adequate. However limitations are also indicated as avenues for further enquiry. / Communication Science / D. Litt. et Phil. (Communication)

Les analyses statistiques ont été réalisées avec le logiciels SPSS 11.0(Statistical Package for Social Sciences) et AMOS 6 (Analysis of Moment Structures. La base de données de l'étude a été crée et receuillie par Caroline Despatie en collaboration avec Dr. Dianne Casoni. / Considérant les effets négatifs sur le développement des enfants associées à l'utilisation de châtiments corporels, un ensemble considérable de la recherche a tenté de proposer une avenue pour interrompre le cercle vicieux de la violence intergénérationnelle. Toutefois, on pourrait argumenter qu`une limitation majeure dans la plupart de ces études réside dans le fait que très peu d`entre eux ont eu comme but d`investiguer l'importance d`une troisième variable comme le sentiment de mériter le châtiment, les explications reçues sur l`équité de la peine imposée ou les attitudes qu`une personne peut garder envers cette méthode éducative. En utilisant la modélisation d'équations structurelles, la présente étude a démontré que la relation apparente entre les variables subjectives et sociodémographiques liés à l`expérience de la punition corporelle et l`intention de faire recours à cette méthode éducative en tant que parent est en fait expliquée par le rôle de médiation joué par d'autres variables telles que les attitudes à l'égard de châtiments corporels, le type de châtiments corporels, la façon dont le châtiment a été perçu par le sujet et les raisons données par l'agent pour motiver la peine infligée. La thèse principale avancée par le présent étude est à l`effet qu`une fois le rôle d`une troisième variable est considéré dans l`équation (par exemple, l'attitude envers les châtiments corporels), l'apparente relation entre les variables objectives et les résultats final, soit l`intention de recourir a la punition corporelle, disparaît. Plus précisément, comme il en résulte de l’analyse de modélisation, ce sont les médiateurs qui expliquent toute association possible entre les variables objectives et l`intention d'utiliser les châtiments corporels. C'est-à-dire, un modèle qui ne contiennent aucune liaison directe entre les variables objectives, et directement mésurables (c'est-à-dire l`âgé lors de la punition, le fait d'être un immigrant, la fréquence de la peine, le nombre d'objets utilisés, le nombre d`agents punisseurs, le sexe) et l'intention d'utiliser les châtiments corporels correspond aux données. De surcroît, parmi les quatre médiateurs pris en compte dans notre modèle, ce sont les opinions à l`égard de la punition corporelle qui possèdent la meilleure capacité prédictive en ce qui a trait à l`intention de recourir aux châtiments corporels. Finalement, afin d'étudier le profil des différences entre les sujets en fonction de leurs expériences passées avec les châtiments corporels, les explications reçues pour la peine, et leurs attitudes, une analyse par groupe a été employée. Bref, une solution en quatre groupes faisant des distinctions significatives entre les groupes a été choisie. / Considering the negative developmental findings associated with the use of parental corporal punishment, a considerable body of research has attempted to suggest an avenue for interrupting this vicious cycle of intergenerational violence. However, a major limitation in most of these studies has to do with the fact that very few of them has looked at the influence of a third variable such as the use of explanation, perceived fairness and deservedness of punishment, or the attitudes one has towards corporal punishment. By employing structural equation modelling (SEM), the present study has demonstrated that the apparent relationship between subjective and socio-demographic variables related to corporal punishment and latter intention to use it as a parent is in fact explained by the mediating role of other variables such as attitudes towards corporal punishment, type of corporal punishment, perceived reasons for punishment and reasons given for punishment by the agent. Our main contention was that when a third variable (e.g., attitude towards corporal punishment) is included in the equation, the apparent relationship between punishment variables and outcome disappears. More specifically, as it has resulted from the SEM analysis, the mediating variables explain all of the association between the objective variables and intention to use corporal punishment. That is to say, a model containing no direct paths from the independent variables (i.e., number of ages punished, being an immigrant, frequency of punishment, means of administration of corporal punishment , number of punishing agents, sex) to Intention to Use Corporal Punishment fits the data. Moreover, among the four mediators considered in our model only the attitudinal measures make a significant contribution to the prediction of intention to use corporal punishment. In addition, in order to explore the profile of differences between subjects on their past experiences with corporal punishment, explanations for punishment, and present attitudes, cluster analysis was employed. Finally, a four cluster solution that made meaningful distinctions between groups was selected for consideration.

Visual perception is a psychological construct that describes the awareness of visual sensations and arise from the interactions of the individual or observer in the external environment together with the physiology of the observer’s visual system. A variety of theories of the development of visual perception have led to the development of different psychometric measures aimed at quantifying the cognitive construct. The Visual Perceptual Aspects Test was developed by Clutten (2009) to measure nine different constructs of visual perception. The original VPAT was validated using content and construct validity based on a Western Cape sample. However, to the researcher’s knowledge, a factor analysis had not yet been conducted on the VPAT to determine the factor validity of the test. Furthermore, no measures of validity or reliability had been conducted on the VPAT using a sample outside of the Western Cape. The aim of this research is to validate the hypothesised nine factor structure of the Visual Perceptual Aspects Test, using a confirmatory factor analysis, exploratory structural equation model, a bifactor confirmatory factor analysis and a bifactor exploratory structural equation model. The results of the analysis showed marginal model fit of the VPAT with the sample data, with sufficient levels of reliability for certain sub-tests. However, the VPAT did not meet significant levels of validity or reliability of the proposed model structure of the VPAT for the sample group of learners based in the Eastern Cape. / Psychology / M.A. (Research Psychology)

Text in English / Developments in Internet technology and pervasive computing over the past two and half decades have resulted in a variety of Web-based applications (WBAs) that provide products and services to online users or customers. The Internet is used not only to transfer information via the web but is increasingly used to provide electronic services including business transactions, information-delivery and social networking, as well as e-government, e-health and e-learning. For such organisations, e-service quality, usability and user experience are considered to be critical determinants of their products’ or services’ success. Many studies to model these three concepts separately have been undertaken as part of broader studies of software quality or service quality modelling. However, to the current researcher’s knowledge, none of the studies have focussed on proposing an evaluation model that integrates and combines the three of them. This research is an effort to fill that gap. The primary purpose of this mixed-methods research was to develop a conceptual integrated model for evaluating e-service quality, usability and user experience (e-SQUUX) of WBAs and then contextualise it to evaluation of a University web portal (UWP). This was undertaken using an exploratory sequential research design. During a qualitative phase, an extensive extensive systematic literature review of 264 relevant sources relating to dimensions of e-service quality, usability and user experience, was undertaken to derive an integrated conceptual e-service quality, usability and user experience (e-SQUUX) Model for evaluating WBAs. The model was then empirically refined through a sequential series of validations, thus developing various versions of the e-SQUUX Model. First, it was content validated by a set of four expert reviewers. Second, during the quantitative phase, in the context of a University web portal, a questionnaire survey was conducted that included a comprehensive pilot study with 29 partipants, prior to the main survey. The main survey data from 174 particiapants was used to determine a validated model, using Exploratory factor analysis (EFA), followed by producing a structural model, using partial least square – structural equation modelling (PLS-SEM). This version consisted of the components of the final e-SQUUX Model. Consequently, the research enriches the body of knowledge on IS and HCI by providing the e-SQUUX Model as an evaluation tool. For designers, developers and managers of UWPs, the model serves as a customisable set of evaluation criteria and also provides specific recommendations for design. In line with the Exploratory sequential design of mixed methods research, the findings of the qualitative work in this research influenced the subsequent quantitative study, since the potential Likert-scale questionnaire items were derived from the definitions and meanings of the components that emanated from the qualitative phase of the study. Consequently, this research is an exemplar for developing an integrated evaluation model for specific facets or domains, and of its application in a particular context, in this case, a University web portal. Keywords: e-service quality, usability, user experience, evaluation model, integrated model, exploratory factor analysis, partial least square – structural equation modelling (PLS-SEM), mixed methods research, Exploratory sequential design, quantitative study, qualitative study, validation, Web-based applications, University web portal / Information System / Ph D. (Information Systems)

La modélisation par équations structurelles est très répandue dans des domaines très variés et nous l'appliquons pour la première fois en métrologie dans le traitement de données de comparaisons interlaboratoires. Les modèles à équations structurelles à variables latentes sont des modèles multivariés utilisés pour modéliser des relations de causalité entre des variables observées (les données). Le modèle s'applique dans le cas où les données peuvent être regroupées dans des blocs disjoints où chaque bloc définit un concept modélisé par une variable latente. La structure de corrélation des variables observées est ainsi résumée dans la structure de corrélation des variables latentes. Nous proposons une approche bayésienne des modèles à équations structurelles centrée sur l'analyse de la matrice de corrélation des variables latentes. Nous appliquons une expansion paramétrique à la matrice de corrélation des variables latentes afin de surmonter l'indétermination de l'échelle des variables latentes et d'améliorer la convergence de l'algorithme de Gibbs utilisé. La puissance de l'approche structurelle nous permet de proposer une modélisation riche et flexible des biais de mesure qui vient enrichir le calcul de la valeur de consensus et de son incertitude associée dans un cadre entièrement bayésien. Sous certaines hypothèses l'approche permet de manière innovante de calculer les contributions des variables de biais au biais des laboratoires. Plus généralement nous proposons un cadre bayésien pour l'amélioration de la qualité des mesures. Nous illustrons et montrons l'intérêt d'une modélisation structurelle des biais de mesure sur des comparaisons interlaboratoires en environnement. / Structural equation modelling is a widespread approach in a variety of domains and is first applied here to interlaboratory comparisons in metrology. Structural Equation Models with latent variables (SEM) are multivariate models used to model causality relationships in observed variables (the data). It is assumed that data can be grouped into separate blocks each describing a latent concept modelled by a latent variable. The correlation structure of the observed variables is transferred into the correlation structure of the latent variables. A Bayesian approach of SEM is proposed based on the analysis of the correlation matrix of latent variables using parameter expansion to overcome identifiability issues and improving the convergence of the Gibbs sampler. SEM is used as a powerful and flexible tool to model measurement bias with the aim of improving the reliability of the consensus value and its associated uncertainty in a fully Bayesian framework. The approach also allows to compute the contributions of the observed variables to the bias of the laboratories, under additional hypotheses. More generally a global Bayesian framework is proposed to improve the quality of measurements. The approach is illustrated on the structural equation modelling of measurement bias in interlaboratory comparisons in environment.

Considérant les effets négatifs sur le développement des enfants associées à l'utilisation de châtiments corporels, un ensemble considérable de la recherche a tenté de proposer une avenue pour interrompre le cercle vicieux de la violence intergénérationnelle. Toutefois, on pourrait argumenter qu`une limitation majeure dans la plupart de ces études réside dans le fait que très peu d`entre eux ont eu comme but d`investiguer l'importance d`une troisième variable comme le sentiment de mériter le châtiment, les explications reçues sur l`équité de la peine imposée ou les attitudes qu`une personne peut garder envers cette méthode éducative. En utilisant la modélisation d'équations structurelles, la présente étude a démontré que la relation apparente entre les variables subjectives et sociodémographiques liés à l`expérience de la punition corporelle et l`intention de faire recours à cette méthode éducative en tant que parent est en fait expliquée par le rôle de médiation joué par d'autres variables telles que les attitudes à l'égard de châtiments corporels, le type de châtiments corporels, la façon dont le châtiment a été perçu par le sujet et les raisons données par l'agent pour motiver la peine infligée. La thèse principale avancée par le présent étude est à l`effet qu`une fois le rôle d`une troisième variable est considéré dans l`équation (par exemple, l'attitude envers les châtiments corporels), l'apparente relation entre les variables objectives et les résultats final, soit l`intention de recourir a la punition corporelle, disparaît. Plus précisément, comme il en résulte de l’analyse de modélisation, ce sont les médiateurs qui expliquent toute association possible entre les variables objectives et l`intention d'utiliser les châtiments corporels. C'est-à-dire, un modèle qui ne contiennent aucune liaison directe entre les variables objectives, et directement mésurables (c'est-à-dire l`âgé lors de la punition, le fait d'être un immigrant, la fréquence de la peine, le nombre d'objets utilisés, le nombre d`agents punisseurs, le sexe) et l'intention d'utiliser les châtiments corporels correspond aux données. De surcroît, parmi les quatre médiateurs pris en compte dans notre modèle, ce sont les opinions à l`égard de la punition corporelle qui possèdent la meilleure capacité prédictive en ce qui a trait à l`intention de recourir aux châtiments corporels. Finalement, afin d'étudier le profil des différences entre les sujets en fonction de leurs expériences passées avec les châtiments corporels, les explications reçues pour la peine, et leurs attitudes, une analyse par groupe a été employée. Bref, une solution en quatre groupes faisant des distinctions significatives entre les groupes a été choisie. / Considering the negative developmental findings associated with the use of parental corporal punishment, a considerable body of research has attempted to suggest an avenue for interrupting this vicious cycle of intergenerational violence. However, a major limitation in most of these studies has to do with the fact that very few of them has looked at the influence of a third variable such as the use of explanation, perceived fairness and deservedness of punishment, or the attitudes one has towards corporal punishment. By employing structural equation modelling (SEM), the present study has demonstrated that the apparent relationship between subjective and socio-demographic variables related to corporal punishment and latter intention to use it as a parent is in fact explained by the mediating role of other variables such as attitudes towards corporal punishment, type of corporal punishment, perceived reasons for punishment and reasons given for punishment by the agent. Our main contention was that when a third variable (e.g., attitude towards corporal punishment) is included in the equation, the apparent relationship between punishment variables and outcome disappears. More specifically, as it has resulted from the SEM analysis, the mediating variables explain all of the association between the objective variables and intention to use corporal punishment. That is to say, a model containing no direct paths from the independent variables (i.e., number of ages punished, being an immigrant, frequency of punishment, means of administration of corporal punishment , number of punishing agents, sex) to Intention to Use Corporal Punishment fits the data. Moreover, among the four mediators considered in our model only the attitudinal measures make a significant contribution to the prediction of intention to use corporal punishment. In addition, in order to explore the profile of differences between subjects on their past experiences with corporal punishment, explanations for punishment, and present attitudes, cluster analysis was employed. Finally, a four cluster solution that made meaningful distinctions between groups was selected for consideration. / Les analyses statistiques ont été réalisées avec le logiciels SPSS 11.0(Statistical Package for Social Sciences) et AMOS 6 (Analysis of Moment Structures. La base de données de l'étude a été crée et receuillie par Caroline Despatie en collaboration avec Dr. Dianne Casoni.

The thesis is based on the Kidscreen Follow-up study. A representative sample of Spanish adolescents and youths and one of their parents were assessed twice (3 years apart) to evaluate adolescents and youths health related quality of life and mental health. The specific objectives of this thesis were to assess the effect of life events, and family and social variables (parents' mental health and home life) on three different health related outcomes: heath related quality of life, mental health, and psychosomatic complaints of adolescents and youths. The Coddington Life Events Scales were adapted into Spanish using the translation and back-translation process. Multiple linear regression and structural equation modelling were used to analyze the effect of the determinants selected. Life events and parents' mental health acted as risk factors for the outcomes selected, specially on mental health outcomes, whereas family factors like the relation with family members in home life were protective factors. Social factors inside the family should be promoted and reinforced to protect adolescents and youths from the effect of risk factors. / Aquesta tesi és part de l'estudi KIDSCREEN Follow-up. Utilitzant una mostra representativa d'adolescents i joves de l'estat espanyol, es van mesurar diferents aspectes relacionats amb la salut, avaluant la mostra dues vegades (amb una separació de 3 anys). Concretament, l'objectiu de la tesi va ser avaluar l'efecte dels aconteixements vitals i factors familiars i socials (salut mental dels pares i vida familiar) en tres resultats en salut: la qualitat de vida relacionada amb la salut, la salut mental i els problemes psicosomàtics dels adolescents i joves. Per això, es va adaptar l'escala Coddington Life Events Scales seguint la metodologia de traducció-retrotraducció. Es van utilizar models de regressió i models d'equacions estructurals per analitzar l'efecte dels determinants en salut. Els aconteixements vitals i la salut mental dels pares van ser dos factors de risc importants, especialment en la salut mental dels adolescents i joves. Per altra banda, les variables familiars com la relació dels membres de la família van actuar com a factors protectors. La cohesió dels membres de la família s'ha de promoure per tal de protegir els adolescents i joves de l'efecte de factors de risc.