abstract: Methods to test hypotheses of mediated effects in the pretest-posttest control group design are understudied in the behavioral sciences (MacKinnon, 2008). Because many studies aim to answer questions about mediating processes in the pretest-posttest control group design, there is a need to determine which model is most appropriate to test hypotheses about mediating processes and what happens to estimates of the mediated effect when model assumptions are violated in this design. The goal of this project was to outline estimator characteristics of four longitudinal mediation models and the cross-sectional mediation model. Models were compared on type 1 error rates, statistical power, accuracy of confidence interval coverage, and bias of parameter estimates. Four traditional longitudinal models and the cross-sectional model were assessed. The four longitudinal models were analysis of covariance (ANCOVA) using pretest scores as a covariate, path analysis, difference scores, and residualized change scores. A Monte Carlo simulation study was conducted to evaluate the different models across a wide range of sample sizes and effect sizes. All models performed well in terms of type 1 error rates and the ANCOVA and path analysis models performed best in terms of bias and empirical power. The difference score, residualized change score, and cross-sectional models all performed well given certain conditions held about the pretest measures. These conditions and future directions are discussed. / Dissertation/Thesis / Masters Thesis Psychology 2015

Oppositional defiant disorder (ODD) is often present already at preschool age. Previous research has established the association between temperament and broad categories of behavioral disorders. However, no longitudinal research has studied the potential impact of temperament on changes in ODD symptoms in preschool and early school years. Two birth cohorts of 4-year olds living in the city of Trondheim, Norway, were screened for emotional and behavioral problems and a subsample oversampled for such problems was drawn to take part in the study; 82.1% consented. Parents of 1000 children were interviewed with the Preschool Age Psychiatric Assessment, and ratings of children's temperament were provided using the Child Behavior Questionnaire (CBQ). Children were reassessed after 2 years (N = 797). The temperamental dimensions Surgency (SU) and Negative Affectivity (NA) were positively correlated with initial level of ODD symptoms, and predicted an increase in symptoms from age 4 to 6. High Effortful Control (EC) was associated with little ODD symptoms at age 4, but did not predict change in such symptoms. However, in interaction with NA, EC was associated with lower initial levels of ODD symptoms and predicted a decrease in symptoms from age 4 to 6. More precisely, the protective effect of EC was very strong for children high on NA but lower for children low to moderate on NA. The findings suggest that NA and SU function as risk factors whereas EC protects against ODD in young children. NA serves as a moderator of EC, in that among children high in NA, EC had a large protective effect, whereas among children with lower levels of NA, EC did protect to a lesser degree against ODD symptoms. Results of this study have theoretical implications linking temperament to ODD in preschoolers, and clinical applications utilizing temperament assessment to identify children at risk, prevent development of ODD and match treatment modalities to the child’s specific temperamental strengths and weaknesses.

Master of Science / Department of Statistics / Haiyan Wang / The purpose of this report is to numerically compare several tests that are applicable to longitudinal data when the experiment contains a large number of treatments or experimental conditions. Such data are increasingly common as technology advances. Of interest is to evaluate if there is any significant main effect of treatment or time, and their interactions. Traditional methods such as linear mixed-effects models (LME), generalized estimating equations (GEE), Wilks' lambda, Hotelling-Lawley, and Pillai's multivariate tests were developed under either parametric distributional assumptions or the assumption of large number of replications. A few recent tests, such as Zhang (2008), Bathke & Harrar (2008), and Bathke & Harrar (2008) were specially developed for the setting of large number of treatments with possibly small replications. In this report, I will present some numerical studies regarding these tests. Performance of these tests will be presented for data generated from several distributions.

Background Qualitative longitudinal research (QLR) has a long history in the social sciences, where its theoretical basis is well established. Qualitative longitudinal (QL) methods are gaining popularity in health care research for exploring the dynamic experience of illness. However, methodological development of QLR is limited within the health literature, and there are very few studies examining the experience of people with colorectal cancer (CRC). Moreover, such studies describe the experiences of those surviving CRC and the voices of those with advanced disease who are approaching the end of their lives remain largely unheard. Aim and objective This study explores the potential of QL interviewing to examine the experiences of those with advanced, metastatic, CRC. I investigate how QL interviews can be best utilised to explore the participants’ accounts of their experiences. I specifically examine the added value and costs of a flexible approach with regard to the frequency and timing of longitudinal interviews. Analytical approaches to QL data are examined to determine their overall value. Methods Sixteen patients with metastatic CRC and eight of their family carers participated in narrative interviews at three time points over the course of a year. The study was designed to include two groups of participants. The first, a routine interval group where interviews were carried out at regular intervals of six months; the second, a flexible interval group where there was an interview at baseline followed by monthly phone calls to track changes in the participants’ circumstances, with a view to conducting the interview as change was occurring. The data were analysed at each time point, and longitudinally using narrative and thematic techniques. Findings The QL design enabled a trusting relationship to evolve, such that private accounts of experience were disclosed. Thus, a nuanced and contextualised understanding of the experience of metastatic CRC materialised. Overall the accounts of CRC were characterised by uncertainty, yet at the same time death was a certainty. Over time, this dual narrative led to participants feeling themselves to be in an ambiguous and liminal state. Some participants described a loss of sense of self, yet others maintained their identity. The work that participants carried out to manage their sense of self changed, as they moved from a collective to an individual identity. In the flexible interval group, monthly telephone calls produced an even more profound research relationship and further enriched the accounts. However, early interviews were only conducted on two occasions and more ethical issues arose as a result of the increased contact. Conclusions By exploring the potential of QL methods, this study has developed the methodology for researching the experiences of those with serious illness. QL interviewing elicits a deep understanding of metastatic CRC that appreciates notions of temporality, process and change. Regular contact with participants between interviews can further enrich the accounts, and is a useful strategy for tracking changes given the unpredictable nature of advanced disease. This thesis showcases the cross-sectional and longitudinal opportunities that QL analysis presents; yet also highlights how longitudinal narrative analysis allows a story to unfold over time which reflects the beginning, the middle and for some the end of the illness experience. Although QL analysis is time consuming, and more contact can amplify ethical issues, the benefits outweigh the constraints.

Clinical practice should be based on the best available evidence. Ideally such evidence is obtained through rigorously conducted, purpose-designed clinical studies such as randomised controlled trials and prospective cohort studies. However gathering information in this way requires a massive effort, can be prohibitively expensive, is time consuming, and may not always be ethical or practicable. When answers are needed urgently and purpose-designed prospective studies are not feasible, retrospective healthcare data may offer the best evidence there is. But can we rely on analysis with such data to give us meaningful answers? The current thesis studies this question through analysis with repeated psychological symptom screening data that were routinely collected from over 20,000 outpatients who attended selected oncology clinics in Scotland. Linked to patients’ oncology records these data offer a unique opportunity to study the progress of distress symptoms on an unprecedented scale in this population. However, the limitations to such routinely collected observational healthcare data are many. We approach the analysis within a missing data context and develop a Bayesian model in WinBUGS to estimate the posterior predictive distribution for the incomplete longitudinal response and covariate data under both Missing At Random and Missing Not At Random mechanisms and use this model to generate multiply imputed datasets for further frequentist analysis. Additional to the routinely collected screening data we also present a purpose-designed, prospective cohort study of distress symptoms in the same cancer outpatient population. This study collected distress outcome scores from enrolled patients at regular intervals and with very little missing data. Consequently it contained many of the features that were lacking in the routinely collected screening data and provided a useful contrast, offering an insight into how the screening data might have been were it not for the limitations. We evaluate the extent to which it was possible to reproduce the clinical study results with the analysis of the observational screening data. Lastly, using the modelling strategy previously developed we analyse the abundant screening data to estimate the prevalence of depression in a cancer outpatient population and the associations with demographic and clinical characteristics, thereby addressing important clinical research questions that have not been adequately studied elsewhere. The thesis concludes that analysis with observational healthcare data can potentially be advanced considerably with the use of flexible and innovative modelling techniques now made practicable with modern computing power.

published_or_final_version / Education / Master / Master of Education

No description available.

Emotional intelligence (EI) encompasses abilities (ability EI; AEI) and self-perceptions (trait EI; TEI) related to the expression, understanding, and management of emotions. Research on its developmental dynamics remains heavily weighted by the AEI perspective, whereas TEI has received virtually no attention in the developmental literature. This is a major oversight, as the two EI components are conceptually distinct and contribute independently to the prediction of important outcomes. Using multi-wave data from the Canadian National Longitudinal Survey of Children and Youth, this project examined rank-order stability (Study 1) and mean-level change (Study 2) in TEI over a 6-year period from late childhood (age 10-11) to adolescence (age 16-17). Longitudinal measurement invariance of the TEI assessment was also tested (Study 1). Longitudinal mean and covariance structures models (Study 1) and latent growth curve models (Study 2) were fitted to the data from 773 children (51% girls) who completed the Emotional Quotient Inventory–Youth Version Brief form at four biannual waves. Principles from the self-concept literature were used to outline an integrative theoretical framework within which the developmental dynamics of TEI could be studied and understood. Study 1 found that three of the four TEI domains could be measured consistently and reliably over time, and that individual differences in these domains became progressively more stable with age. Contrary to the maturity principle guiding the development of AEI, Study 2 found that mean-level changes in TEI followed a curvilinear trajectory characterizing the development of self-concepts: EI self-perceptions declined between late childhood and early adolescence and then increased later in adolescence. These findings provide, for the first time, important validity evidence for the TEI construct as developmentally distinct from AEI and developmentally similar to self-concept. From an applied standpoint, this implies that enhancing EI abilities alone may not necessarily result in concomitant increases in EI self-concepts, and vice versa. Instead, both AEI and TEI may need to be targeted to maximize the effectiveness of intervention efforts. From a theoretical standpoint, the conceptual link between TEI and self-concept theories suggests that other properties of self-concepts might also generalize to TEI – an important avenue for future research. / Thesis (Ph.D, Psychology) -- Queen's University, 2013-01-29 17:40:30.322

Long bone lengthening occurs at the growth plate (GP) by well-regulated chondrocyte proliferation, hypertrophy and terminal matrix deposition. GP chondrocyte (GPC) hypertrophy has been implicated to be the main determinant of bone growth rate; however the mechanism is poorly understood. The work of this thesis examined some of the cellular process that drives the chondrocyte swelling or hypertrophy particularly in a mammalian post natal GPs using living in situ GPC and fixed GP tissues. Confocal scanning microscopy (CLSM) was used to determine living in situ GPC volume and dimension changes in proliferative zone (PZ) through to hypertrophic zone (HZ) chondrocytes of different GPs of various bones. While PZ cells showed similar volumes and dimensions, HZ cells varied in different GPs, even within the same long bone but at opposite ends. However, the hypertrophic cell volume measured at a single post natal age (day 7) was independent of the corresponding bone length. This could reflect a complex interplay between local and systemic factors in different GPs, which occurs throughout the active phase of bone growth. Maintaining GPC morphology was critical in studying GPC hypertrophy using fixed tissues. This work highlighted a problem caused by conventional fixative solutions, which caused up to 44% hypertrophic GPC shrinkage following GP fixation. This artifact appeared to be associated with the hyperosmotic nature of the fixatives used and could be abolished by adjusting the fixative osmolarity close to physiological level (280 mOsm), or could be significantly reduced by bisecting bone tissues prior to tissue fixation. This thesis proposed roles for plasma membrane transporter(s) in mediating GPC hypertrophy. This hypothesis was tested by examining roles of sodium-hydrogen exchanger (NHE) and anion exchanger (AE) in GPC hypertrophy using an ex vivo bone growth inhibition model. Inhibition of bone growth by inhibitors of NHE (EIPA) and AE (DIDS) respectively was shown to be dose-dependent. The histology of bones demonstrated that the late HZ width was significantly reduced in GPs treated with EIPA or DIDS. Although in situ GPC volumes in the PZ and HZ were not notably different in DIDS-treated GP, the cell volumes in both zones were significantly reduced by EIPA treatment. Fluorescence immunohistochemistry revealed distinctive cellular localisations of NHE1 and AE2 in the PZ and early HZ. These results suggest a possible role of AE in mediating GPC volume increase in PZ chondrocytes and those in the early stages of cell hypertrophy, whereas NHE could possibly maintain intracellular pH of GPC throughout all GP zones. This thesis has characterized various changes in volume and dimensions of living in situ GPC from PZ through to HZ of different GPs of postnatal rats. This work emphasized the importance of fixative osmolarity in order to accurately preserve the normal volume/morphology of cells within tissues. Most importantly, this thesis confirmed a potential role of the plasma membrane transporters, AE and NHE in GPC hypertrophy of growing bones.

In this submission, five articles are presented examining one theme: diagnosis of autism spectrum disorders (ASD) in children. Three articles provides perspectives on various social and medical factors that influence the diagnosis of ASD, and the others examine social and behavioural outcomes for children diagnosed with ASD. One article provides an in depth examination of the dilemmas of diagnosis from a parental perspective. The research utilized both qualitative and quantitative methods. A secondary analysis of a longitudinal birth cohort study revealed that there were a number of children who had autistic traits equally severe as those with clinical diagnosis. Further analysis exposed a possible gender bias in diagnosis. Outcomes for children with ASD diagnoses were worse than for those without diagnoses but with comparable behaviours as preschoolers. ASD diagnosis apparently had no positive effect on the developmental trajectory of prosocial behaviour. The implications of these results are discussed. Analysis of qualitative data collected in semi-structured interviews with parents of both diagnosed and undiagnosed children exposed dilemmas faced by parents as they contemplated an ASD diagnosis and highlighted parental action to de-stigmatise the condition after diagnosis had been applied. The body of work as a whole falls at the junction of clinical and educational psychology, developmental psychology, social psychology, social psychiatry, sociology and epidemiology. It draws attention to a number of social processes that contribute to ASD diagnosis. Overall, it is argued, the work supports the conceptualisation of ASD as both a biologically and socially determined condition.