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1. Yanosky, Daniel J. Comparability of covariance structures and accuracy of information criteria in mixed model methods for longitudinal data analysis.
Degree: PhD, Educational Psychology, 2007, University of Georgia
URL: http://purl.galileo.usg.edu/uga_etd/yanosky_daniel_j_200705_phd
► Modern mixed model methods for analyzing longitudinal data require researchers to select a covariance structure for the data to fully specify the model and obtain… (more)
▼ Modern mixed model methods for analyzing longitudinal data require researchers to select a covariance structure for the data to fully specify the model and obtain statistical tests of the fixed effects. The current study is a Monte Carlo simulation with primary purposes to 1) identify surrogate covariance structures for seven known models and estimate the severity of committing an error in covariance specification in terms of empirical Type I error rates and statistical power, 2) estimate accuracy rates of five information criteria in selecting appropriate covariance structures, and 3) estimate the empirical Type I error rates and power for models chosen by each information criterion. Data were generated corresponding to a single group repeated measures design with N = 10, 30, or 60 subjects and a quantitative response variable measured over t = 3 or 6 occasions. Other salient variables included the magnitude of serial correlation, presence of non-constant variance, and so forth. Data were generated under 72 conditions with 10,000 replications per condition. Statistical Analysis System (SAS) version 9.1 and R version 2.4.0 were used to generate and analyze the data. A preliminary investigation demonstrated that the Kenward-Roger degrees of freedom approximation yields F-tests for the mixed models with superior Type I error control compared to the Between/Within method, Satterthwaite approximation, and the sandwich estimator. Results corresponding to the primary research questions demonstrated 1) seven covariance structures were found to be acceptable approximations of a given true model in 14 instances, 2) rates of selecting appropriate covariance structures for information criteria were found to be substantially influenced by accounting for surrogate structures with a rate of 69% for both AIC and BIC, 3) empirical Type I error rates were found to be slightly conservative and therefore well controlled and power estimates comparable when models were selected by AIC, AICC, HQIC, BIC, and CAIC. Secondary investigations compared the performance of mixed models with classical methods and evaluated the empirical Type I error control of the Group x Time interaction test. The implications of these findings are discussed and heuristics for applied researchers working with this variety of data are suggested. Advisors/Committee Members: Stephen Olejnik.
Subjects/Keywords: Longitudinal data analysis
Yanosky, D. J. (2007). Comparability of covariance structures and accuracy of information criteria in mixed model methods for longitudinal data analysis . (Doctoral Dissertation). University of Georgia. Retrieved from http://purl.galileo.usg.edu/uga_etd/yanosky_daniel_j_200705_phd
Yanosky, Daniel J. "Comparability of covariance structures and accuracy of information criteria in mixed model methods for longitudinal data analysis." 2007. Doctoral Dissertation, University of Georgia. Accessed January 18, 2020. http://purl.galileo.usg.edu/uga_etd/yanosky_daniel_j_200705_phd.
Yanosky, Daniel J. "Comparability of covariance structures and accuracy of information criteria in mixed model methods for longitudinal data analysis." 2007. Web. 18 Jan 2020.
Yanosky DJ. Comparability of covariance structures and accuracy of information criteria in mixed model methods for longitudinal data analysis. [Internet] [Doctoral dissertation]. University of Georgia; 2007. [cited 2020 Jan 18]. Available from: http://purl.galileo.usg.edu/uga_etd/yanosky_daniel_j_200705_phd.
Yanosky DJ. Comparability of covariance structures and accuracy of information criteria in mixed model methods for longitudinal data analysis. [Doctoral Dissertation]. University of Georgia; 2007. Available from: http://purl.galileo.usg.edu/uga_etd/yanosky_daniel_j_200705_phd
2. Li, Xiaomei. Approaches to Modelling Heterogeneity in Longitudinal Studies.
Degree: 2011, Victoria University of Wellington
► This thesis is about estimation bias of longitudinal data when there is correlation between the explanatory variable and the individual effect. In our study, we… (more)
▼ This thesis is about estimation bias of longitudinal data when there is correlation between the explanatory variable and the individual effect. In our study, we firstly introduce what is longitudinal data, then we introduce the commonly used estimation methods for the general linear model: the least squares method and maximum likelihood method. We apply these estimation methods to three simple general models which are commonly used to analyse longitudinal data. Secondly, we use frequentist and Bayesian analysis to explore the estimation bias theoretically and empirically, with an emphasis on the heterogeneity bias. This bias occurs where random effect estimation is used to analyse data with nonzero correlation between explanatory variables and the individual effect. We then empirically compare the estimated value with the true value. In this way, we demonstrate and verify the theoretical formulation which can be used to determine the size of the bias [Mundlak, 1978]. In order to avoid the estimation bias, the fixed effect estimation should be used to get the better solution under nonzero correlation situation. The Hausman test is used to confirm this. However, the bias not only occurs when we use frequentist analysis, but also exist by using the Bayesian estimation of random effect model. Finally, we follow the Mundlak [1978] idea, then define the special Bayesian model which can be used as Hausman test and as a comparable model. We also prove that it is best fit model among the random effect, fixed effect and pooled model if there is correlation between explanatory variables and individual effect. Throughout this thesis, we illustrate this ideas using examples based on real and simulated data. Advisors/Committee Members: Arnold, Richard.
Subjects/Keywords: Longitudinal data analysis; Estimation bias
Li, X. (2011). Approaches to Modelling Heterogeneity in Longitudinal Studies . (Masters Thesis). Victoria University of Wellington. Retrieved from http://hdl.handle.net/10063/1695
Li, Xiaomei. "Approaches to Modelling Heterogeneity in Longitudinal Studies." 2011. Masters Thesis, Victoria University of Wellington. Accessed January 18, 2020. http://hdl.handle.net/10063/1695.
Li, Xiaomei. "Approaches to Modelling Heterogeneity in Longitudinal Studies." 2011. Web. 18 Jan 2020.
Li X. Approaches to Modelling Heterogeneity in Longitudinal Studies. [Internet] [Masters thesis]. Victoria University of Wellington; 2011. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/10063/1695.
Li X. Approaches to Modelling Heterogeneity in Longitudinal Studies. [Masters Thesis]. Victoria University of Wellington; 2011. Available from: http://hdl.handle.net/10063/1695
3. Marks, Jennifer. Living in Sin, In Sickness and In Health? An Investigation of Cohabitation, Marriage, and Health.
Degree: PhD, Sociology, 2009, North Carolina State University
URL: http://www.lib.ncsu.edu/resolver/1840.16/5128
► The physical and psychological health benefits of marriage have been well-documented in the family and medical sociology literature. Given the recent increases in the prevalence… (more)
▼ The physical and psychological health benefits of marriage have been well-documented in the family and medical sociology literature. Given the recent increases in the prevalence of cohabitation, this research asks whether marriage still confers the same health benefits, and whether cohabitation might do the same. Using two waves of a nationally representative sample, the effects of union type on eleven health outcomes were examined, both cross-sectionally and longitudinally; processual factors such as social support, health behaviors, and socioeconomic status were also examined. Union type was not a consistent predictor of health outcomes: spouses appear somewhat better off than singles, but major differences between cohabitation and marriage were not found. Further, the health benefits of marriage are primarily afforded to men, and the benefits of both union types are more pronounced for younger persons. Social support was a consistent and positive predictor of physical and psychological health, although men may receive greater benefits than women. Health behavior measures were not effective predictors of health outcomes, but this may be due to measurement issues. Socioeconomic status measures were also consistent predictors of physical and psychological health, although an individual's employment was more often significant than total household income. Additional analyses were conducted to test the "selection hypothesis†– that healthier people are more likely to enter unions. Results are supportive of selective effects for marriage, but not nearly as much so for cohabitation, implying that perhaps different mate selection processes are at work for the two union types. Theoretical, research, and policy implications are discussed. Advisors/Committee Members: Theodore N. Greenstein, Committee Chair (advisor), Virginia Aldige' Hiday, Committee Member (advisor), Feinian Chen, Committee Member (advisor), Ronald Czaja, Committee Member (advisor).
Subjects/Keywords: longitudinal analysis; cohabitation; marriage; health
Marks, J. (2009). Living in Sin, In Sickness and In Health? An Investigation of Cohabitation, Marriage, and Health . (Doctoral Dissertation). North Carolina State University. Retrieved from http://www.lib.ncsu.edu/resolver/1840.16/5128
Marks, Jennifer. "Living in Sin, In Sickness and In Health? An Investigation of Cohabitation, Marriage, and Health." 2009. Doctoral Dissertation, North Carolina State University. Accessed January 18, 2020. http://www.lib.ncsu.edu/resolver/1840.16/5128.
Marks, Jennifer. "Living in Sin, In Sickness and In Health? An Investigation of Cohabitation, Marriage, and Health." 2009. Web. 18 Jan 2020.
Marks J. Living in Sin, In Sickness and In Health? An Investigation of Cohabitation, Marriage, and Health. [Internet] [Doctoral dissertation]. North Carolina State University; 2009. [cited 2020 Jan 18]. Available from: http://www.lib.ncsu.edu/resolver/1840.16/5128.
Marks J. Living in Sin, In Sickness and In Health? An Investigation of Cohabitation, Marriage, and Health. [Doctoral Dissertation]. North Carolina State University; 2009. Available from: http://www.lib.ncsu.edu/resolver/1840.16/5128
4. Longstaff, Tessa. Analysis of longitudinal data in perinatal trials when the length of follow-up is informative.
URL: http://hdl.handle.net/2440/100192
► Background: Most commonly used statistical methods assume that the data consist of independent observations. Clustered data occur in many settings, such as longitudinal studies, where… (more)
▼ Background: Most commonly used statistical methods assume that the data consist of independent observations. Clustered data occur in many settings, such as longitudinal studies, where outcomes are repeatedly measured over time on each subject. Observations from the same subject are dependent and hence form a cluster. Two commonly used methods of analysis for clustered data are mixed models and generalised estimating equations (GEEs). Additional complexity arises when analysing clustered data where the cluster size is informative; that is, where the cluster size is related to the outcome. Most methods of analysis for clustered data, including mixed models and GEEs, generally assume non informative cluster size and hence may not be suitable when the cluster size is informative. Aim: The aim of this thesis is to compare methods for analysing longitudinal data when the cluster size (length of follow up) is informative. Methods: Both real and simulated data were used to compare methods for analysing clustered data with informative cluster size. A range of methods were considered including: GEEs with independent, autoregressive or exchangeable working correlation structures; cluster weighted GEEs; and mixed models. The real data come from a perinatal trial (the POPPET trial), which investigated the effect of high versus standard protein content human milk fortifier on the growth of 60 preterm infants. This dataset was used to investigate different methods of analysis for estimating the effect of treatment on infant growth when informative cluster size was suspected. As real data cannot be used to show which methods of analysis are performing best in general, a simulation study was conducted to compare methods when the true parameter values were known. The data were simulated based on the POPPET trial. Different treatment effects, sample sizes, and correlations between the cluster size and the outcomes were considered. Results: For the POPPET trial, evidence of informative cluster size was found. Different methods of analysis produced quite different parameter estimates but similar conclusions about the effect of the intervention. The simulation results showed that when cluster size was non informative, all methods performed very well. When cluster size was informative, mixed models and autoregressive GEEs always performed well. However, the independence, exchangeable and cluster weighted GEEs often produced low coverage probabilities and model based standard errors that differed from the standard deviation of the parameter estimates. These methods generally performed better when the trial size was larger and when there was no correlation between individual growth trajectories and cluster size. Conclusions: It is recommended that mixed models or autoregressive GEEs be used to analyse longitudinal data with informative cluster size in general, including the POPPET trial data. Independence, exchangeable and cluster weighted GEEs should only be used when the sample size is large and there is no correlation between individual… Advisors/Committee Members: Glonek, Garique Francis Vladimir (advisor), Yellend, Lisa (advisor), School of Mathematical Sciences (school).
Subjects/Keywords: longitudinal data; analysis; perinatal trial
Longstaff, T. (2016). Analysis of longitudinal data in perinatal trials when the length of follow-up is informative . (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/100192
Longstaff, Tessa. "Analysis of longitudinal data in perinatal trials when the length of follow-up is informative." 2016. Thesis, University of Adelaide. Accessed January 18, 2020. http://hdl.handle.net/2440/100192.
Longstaff, Tessa. "Analysis of longitudinal data in perinatal trials when the length of follow-up is informative." 2016. Web. 18 Jan 2020.
Longstaff T. Analysis of longitudinal data in perinatal trials when the length of follow-up is informative. [Internet] [Thesis]. University of Adelaide; 2016. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/2440/100192.
Longstaff T. Analysis of longitudinal data in perinatal trials when the length of follow-up is informative. [Thesis]. University of Adelaide; 2016. Available from: http://hdl.handle.net/2440/100192
5. Emery, Cécile. Investigating leadership emergence using longitudinal leadership networks.
Degree: 2010, Università della Svizzera italiana
URL: http://doc.rero.ch/record/19029
► A growing body of research has examined emergent leadership within groups. Emergent leadership is defined as a process during which some individuals, over time and… (more)
▼ A growing body of research has examined emergent leadership within groups. Emergent leadership is defined as a process during which some individuals, over time and through social interaction, are recognized and accepted as leaders by the group. Interestingly, although there is much theorizing about how leadership emerges and about the individual characteristics facilitating the emergence of leaders, there is still very little about knowledge about this particular dynamic social process, and this is especially true if we expand our view of leadership beyond the leader-follower dyad. To refine our understanding of leadership emergence, I built my investigations on previous research on Distributed Leadership which recommends the use of social network analysis to study how leadership may be shared among several individuals. By envisioning leadership as a network of perceptions, where nodes and ties represent actors and leadership nominations respectively, a complex and multi-level representation of leadership is gathered. While social network analysis has been successfully applied to study distributed leadership using a cross-sectional approach, leadership emergence occurs over time and an analysis of this phenomenon would benefit from the use of a longitudinal perspective. I therefore collected leadership networks over several periods of time and used SIENA, a novel multilevel statistical procedure for longitudinal analysis of social networks, to examine, through three manuscripts, (i) How emergent leaders are the result of group processes?, (ii) Do emergent leaders perceive themselves as leaders? and (iii) Are emergent leaders emotionally intelligence? Advisors/Committee Members: Erik (Dir.).
Subjects/Keywords: Longitudinal social network analysis
Emery, C. (2010). Investigating leadership emergence using longitudinal leadership networks . (Thesis). Università della Svizzera italiana. Retrieved from http://doc.rero.ch/record/19029
Emery, Cécile. "Investigating leadership emergence using longitudinal leadership networks." 2010. Thesis, Università della Svizzera italiana. Accessed January 18, 2020. http://doc.rero.ch/record/19029.
Emery, Cécile. "Investigating leadership emergence using longitudinal leadership networks." 2010. Web. 18 Jan 2020.
Emery C. Investigating leadership emergence using longitudinal leadership networks. [Internet] [Thesis]. Università della Svizzera italiana; 2010. [cited 2020 Jan 18]. Available from: http://doc.rero.ch/record/19029.
Emery C. Investigating leadership emergence using longitudinal leadership networks. [Thesis]. Università della Svizzera italiana; 2010. Available from: http://doc.rero.ch/record/19029
6. Li, Ying. Internal Migration in the Survey of Family, Income and Employment (SoFIE).
► This thesis studies the short term outcomes in family annual income changes associated with internal migration in New Zealand. This is carried out through analysis… (more)
▼ This thesis studies the short term outcomes in family annual income changes associated with internal migration in New Zealand. This is carried out through analysis of the unit record dataset produced from the Survey of Family, Income and Employment (SoFIE) which is a longitudinal social survey undertaken by Statistics New Zealand starting in October 2002. Results from data analysis shows us that family migration status and time of measurement have a close relationship with family annual income. Moveover, family structure, average age of adult members in a family, education level of family members, ownership of family residential property and the number of dependent children in a family are all factors related to family annual income. We apply the General Linear Mixed Model to control these confounding variables and explore the relationship between migration status and annual income of a family. The results from our final model show that changes in the family annual income from before to after their internal migration are different for families. The difference depends on the average age of adult family members. Families with a younger average age benefit from internal migration: their family annual incomes are increased shortly after their movement. In contrast, families with a older average age experience a loss of income. Advisors/Committee Members: Liu, Ivy, Arnold, Richard.
Subjects/Keywords: Internal migration families; Longitudinal analysis; Longitudinal survey; SoFIE
Li, Y. (2010). Internal Migration in the Survey of Family, Income and Employment (SoFIE) . (Masters Thesis). Victoria University of Wellington. Retrieved from http://hdl.handle.net/10063/1809
Li, Ying. "Internal Migration in the Survey of Family, Income and Employment (SoFIE)." 2010. Masters Thesis, Victoria University of Wellington. Accessed January 18, 2020. http://hdl.handle.net/10063/1809.
Li, Ying. "Internal Migration in the Survey of Family, Income and Employment (SoFIE)." 2010. Web. 18 Jan 2020.
Li Y. Internal Migration in the Survey of Family, Income and Employment (SoFIE). [Internet] [Masters thesis]. Victoria University of Wellington; 2010. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/10063/1809.
Li Y. Internal Migration in the Survey of Family, Income and Employment (SoFIE). [Masters Thesis]. Victoria University of Wellington; 2010. Available from: http://hdl.handle.net/10063/1809
7. Holm Hansen, Christian. Analysis of routinely collected repeated patient outcomes.
► 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… (more)
▼ 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.
Subjects/Keywords: 610.72; medical statistics; missing data; longitudinal analysis
Holm Hansen, C. (2014). Analysis of routinely collected repeated patient outcomes . (Doctoral Dissertation). University of Edinburgh. Retrieved from http://hdl.handle.net/1842/9556
Holm Hansen, Christian. "Analysis of routinely collected repeated patient outcomes." 2014. Doctoral Dissertation, University of Edinburgh. Accessed January 18, 2020. http://hdl.handle.net/1842/9556.
Holm Hansen, Christian. "Analysis of routinely collected repeated patient outcomes." 2014. Web. 18 Jan 2020.
Holm Hansen C. Analysis of routinely collected repeated patient outcomes. [Internet] [Doctoral dissertation]. University of Edinburgh; 2014. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/1842/9556.
Holm Hansen C. Analysis of routinely collected repeated patient outcomes. [Doctoral Dissertation]. University of Edinburgh; 2014. Available from: http://hdl.handle.net/1842/9556
8. Russell, Ginny. Diagnosing autism spectrum disorders in children : medical and social perspectives.
Degree: PhD, 2010, University of Exeter
► 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… (more)
▼ 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.
Subjects/Keywords: 155; Autism : pervasive developmental disorder : longitudinal analysis
Russell, G. (2010). Diagnosing autism spectrum disorders in children : medical and social perspectives . (Doctoral Dissertation). University of Exeter. Retrieved from http://hdl.handle.net/10036/3188
Russell, Ginny. "Diagnosing autism spectrum disorders in children : medical and social perspectives." 2010. Doctoral Dissertation, University of Exeter. Accessed January 18, 2020. http://hdl.handle.net/10036/3188.
Russell, Ginny. "Diagnosing autism spectrum disorders in children : medical and social perspectives." 2010. Web. 18 Jan 2020.
Russell G. Diagnosing autism spectrum disorders in children : medical and social perspectives. [Internet] [Doctoral dissertation]. University of Exeter; 2010. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/10036/3188.
Russell G. Diagnosing autism spectrum disorders in children : medical and social perspectives. [Doctoral Dissertation]. University of Exeter; 2010. Available from: http://hdl.handle.net/10036/3188
9. [No author]. Some new applications of Bayesian longitudinal models.
Degree: 2016, Baylor University
► In this dissertation we consider some novel applications of Bayesian longitudinal methods. As inference is generally focused on response of an individual, we work within… (more)
▼ In this dissertation we consider some novel applications of Bayesian longitudinal methods. As inference is generally focused on response of an individual, we work within the mixed model framework. The two applications are described below. Our first application is to a data set containing measurements of the probability of collision between two space objects orbiting the Earth. These measurements are longitudinal in nature, as they are observed over time and vary according to which two satellites they are taken on. This application presents a number of specific challenges, such as measurements at irregular time intervals, sparse data, and a bounded response variable. The second application is that of longitudinal network meta-analysis. In clinical trials, one major question is how to compare treatments across trials. However, current methods usually only deal with comparisons at a single time point, discarding data at other time points. This problem presents different challenges from the previous, such as defining network treatment effects over time, developing diagnostic methods for choosing a correct model, and dual longitudinal models for the mean and variance. Advisors/Committee Members: Stamey, James D (advisor), Hejduk, Matthew Dickerson, 1967- (advisor).
Subjects/Keywords: Longitudinal data. Meta-analysis. Beta regression. Bayesian.
author], [. (2016). Some new applications of Bayesian longitudinal models. (Thesis). Baylor University. Retrieved from http://hdl.handle.net/2104/9804
author], [No. "Some new applications of Bayesian longitudinal models. " 2016. Thesis, Baylor University. Accessed January 18, 2020. http://hdl.handle.net/2104/9804.
author], [No. "Some new applications of Bayesian longitudinal models. " 2016. Web. 18 Jan 2020.
author] [. Some new applications of Bayesian longitudinal models. [Internet] [Thesis]. Baylor University; 2016. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/2104/9804.
author] [. Some new applications of Bayesian longitudinal models. [Thesis]. Baylor University; 2016. Available from: http://hdl.handle.net/2104/9804
10. Benson, Lizbeth Erin. Fusing biodiversity metrics into investigations of daily life and healthy aging: Illustrations and recommendations with emodiversity.
Degree: MS, Human Development and Family Studies, 2016, Penn State University
URL: https://etda.libraries.psu.edu/catalog/13528leb237
► Objectives. Functionalist theories of emotion and models of biodiversity suggest links between diversity of the (emotional) ecosystem and health. This paper examines how diversity-type intraindividual… (more)
▼ Objectives. Functionalist theories of emotion and models of biodiversity suggest links between diversity of the (emotional) ecosystem and health. This paper examines how diversity-type intraindividual variability constructs – particularly emodiversity - can be articulated using intensive longitudinal data. Method. Using data from a daily diary study (T = 30) of middle-age adults (N = 138; Sturgeon, Zautra, & Okun, 2014) to examine emodiversity in day-to-day life, we consider how item selection, measurement scale, number of occasions, and choice of diversity index map to theory, measurement reliability, and empirical inquiry. Results. The number of items, response scale, and choice of index have limited influence on measurement of diversity, while number of occasions and theoretical stance play important roles in terms of reliability and interpretation. The empirical examples suggests that at lower levels of positive and negative emodiversity, lower (-1 SD) mean positive and negative emotion were protective of physical health, whereas at higher levels of emodiversity, physical health was relatively high regardless of the level of mean emotion. Discussion. This study highlights the utility of intensive longitudinal data for operationalization of dynamic constructs, provides recommendations for calculating diversity-based IIV constructs, and illustrates the utility of emodiversity in studies of healthy aging.
Subjects/Keywords: longitudinal analysis; emotion; diversity; intraindividual variability
Benson, L. E. (2016). Fusing biodiversity metrics into investigations of daily life and healthy aging: Illustrations and recommendations with emodiversity . (Masters Thesis). Penn State University. Retrieved from https://etda.libraries.psu.edu/catalog/13528leb237
Benson, Lizbeth Erin. "Fusing biodiversity metrics into investigations of daily life and healthy aging: Illustrations and recommendations with emodiversity." 2016. Masters Thesis, Penn State University. Accessed January 18, 2020. https://etda.libraries.psu.edu/catalog/13528leb237.
Benson, Lizbeth Erin. "Fusing biodiversity metrics into investigations of daily life and healthy aging: Illustrations and recommendations with emodiversity." 2016. Web. 18 Jan 2020.
Benson LE. Fusing biodiversity metrics into investigations of daily life and healthy aging: Illustrations and recommendations with emodiversity. [Internet] [Masters thesis]. Penn State University; 2016. [cited 2020 Jan 18]. Available from: https://etda.libraries.psu.edu/catalog/13528leb237.
Benson LE. Fusing biodiversity metrics into investigations of daily life and healthy aging: Illustrations and recommendations with emodiversity. [Masters Thesis]. Penn State University; 2016. Available from: https://etda.libraries.psu.edu/catalog/13528leb237
11. Liu, Kai. Statistical Analysis of Longitudinal Data with a Case Study.
Degree: MSc, 2015, McMaster University
Preterm birth is the leading cause of neonatal mortality and long-term morbidity. Neonatologists can adjust nutrition to preterm neonates to control their weight gain so… (more)
Preterm birth is the leading cause of neonatal mortality and long-term morbidity. Neonatologists can adjust nutrition to preterm neonates to control their weight gain so that the possibility of long-term morbidity can be minimized. This optimization of growth trajectories of preterm infants can be achieved by studying a cohort of selected healthy preterm infants with weights observed during day 1 to day 21. However, missing values in such a data poses a big challenge in this case. In fact, missing data is a common problem faced by most applied researchers. Most statistical softwares deal with missing data by simply deleting subjects with missing items. Analyses carried out on such incomplete data result in biased estimates of the parameters of interest and consequently lead to misleading or invalid inference. Even though many statistical methods may provide robust analysis, it will be better to handle missing data by imputing them with plausible values and then carry out a suitable analysis on the full data. In this thesis, several imputation methods are first introduced and discussed. Once the data get completed by the use of any of these methods, the growth trajectories for this cohort of preterm infants can be presented in the form of percentile growth curves. These growth trajectories can now serve as references for the population of preterm babies. To find out the explicit growth rate, we are interested in establishing predictive models for weights at days 7, 14 and 21. I have used both univariate and multivariate linear models on the completed data. The resulting predictive models can then be used to calculate the target weight at days 7, 14 and 21 for any other infant given the information at birth. Then, neonatologists can adjust the amount of nutrition given in order to preterm infants to control their growth so that they will not grow too fast or too slow, thus avoiding later-life complications.
Advisors/Committee Members: Narayanaswamy, Balakrishnan, Mathematics and Statistics.
Subjects/Keywords: preterm birth; longitudinal data; imputation; statistical analysis
Liu, K. (2015). Statistical Analysis of Longitudinal Data with a Case Study . (Masters Thesis). McMaster University. Retrieved from http://hdl.handle.net/11375/16614
Liu, Kai. "Statistical Analysis of Longitudinal Data with a Case Study." 2015. Masters Thesis, McMaster University. Accessed January 18, 2020. http://hdl.handle.net/11375/16614.
Liu, Kai. "Statistical Analysis of Longitudinal Data with a Case Study." 2015. Web. 18 Jan 2020.
Liu K. Statistical Analysis of Longitudinal Data with a Case Study. [Internet] [Masters thesis]. McMaster University; 2015. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/11375/16614.
Liu K. Statistical Analysis of Longitudinal Data with a Case Study. [Masters Thesis]. McMaster University; 2015. Available from: http://hdl.handle.net/11375/16614
University of Illinois – Chicago
12. Zulauf, Courtney A. Profiles of School-Based Peer Aggression.
Degree: 2016, University of Illinois – Chicago
► Research on school-based aggression has often described children's involvement in peer aggression as either a target or aggressor and has not explored how children may… (more)
▼ Research on school-based aggression has often described children's involvement in peer aggression as either a target or aggressor and has not explored how children may endorse various levels of involvement. Using Latent Class Analysis, this study identified profiles of school-based peer aggression among the same sample of children in third and again in sixth grade. The sample consisted of 927 children who were part of the National Institute of Child Health and Human Development Study of Early Childcare and Youth Development. Several profiles emerged indicating various levels of involvement as well as the use of different forms of aggression (physical and verbal). The main profiles that emerged were children who endorsed being both perpetrators and targets, children who endorsed being targets, and children who endorsed low involvement. Further analysis revealed that profiles did not fit equally well for boys and girls. Self-reported involvement increased from third to sixth grade with the main differences emerging because boys endorsed being strictly a verbal and physical aggressor and girls endorsed being aggressors and targets of verbal aggression only. Parent reports of children's externalizing and internalizing problems as well as teacher perceptions of the children's social behavior were incorporated into the study in order to describe each profile in more detail. The findings of this study indicate that child involvement in school-based peer aggression is complex with children endorsing various levels of involvement, perpetrating or being targeted, throughout the school year. Advisors/Committee Members: Zinsser, Katherine M. (advisor), Roy, Amanda (committee member), Weissberg, Roger (committee member).
Subjects/Keywords: peer aggression; victimization; latent class analysis; longitudinal
Zulauf, C. A. (2016). Profiles of School-Based Peer Aggression . (Thesis). University of Illinois – Chicago. Retrieved from http://hdl.handle.net/10027/21271
Zulauf, Courtney A. "Profiles of School-Based Peer Aggression." 2016. Thesis, University of Illinois – Chicago. Accessed January 18, 2020. http://hdl.handle.net/10027/21271.
Zulauf, Courtney A. "Profiles of School-Based Peer Aggression." 2016. Web. 18 Jan 2020.
Zulauf CA. Profiles of School-Based Peer Aggression. [Internet] [Thesis]. University of Illinois – Chicago; 2016. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/10027/21271.
Zulauf CA. Profiles of School-Based Peer Aggression. [Thesis]. University of Illinois – Chicago; 2016. Available from: http://hdl.handle.net/10027/21271
13. Coelho, Liliana Rodrigues. Modelos longitudinais e de sobrevivência para a recidiva do cancro da mama .
Degree: 2017, Universidade do Minho
► O interesse por esta temática deve-se à complexidade e mistério que ainda envolve uma doença que nos afeta, principalmente a nós mulheres e que, infelizmente,… (more)
▼ O interesse por esta temática deve-se à complexidade e mistério que ainda envolve uma doença que nos afeta, principalmente a nós mulheres e que, infelizmente, não obstante a ciência ter evoluído imenso na área da investigação, continua ainda a intrigar-nos pela evolução e desfecho que a própria doença envolve. O objetivo é inferir sobre os fatores de risco que afetam a sobrevivência para a recidiva do cancro da mama. Analisando também os fatores de risco que afetam a progressão no tempo de dois marcadores tumorais, o marcador CA15.3 e o marcador CEA. Para a análise de sobrevivência recorreu-se ao estimador de Kaplan-Meier e ao modelo de riscos proporcionais de Cox. Os modelos lineares generalizados foram utilizados para estudar a evolução dos marcadores tumorais. Após análise individual das variáveis ajustamos os dois modelos longitudinais multivariados, considerando o efeito conjunto de covariáveis, um para cada marcador, adotando a metodologia de efeitos aleatórios Concluímos que as variáveis, triplo negativo, tamanho do tumor e idade ao diagnóstico têm efeito na probabilidade de recidiva do tumor. Na progressão do marcador CA15.3, as variáveis, idade ao diagnóstico, imagens de invasão vascular venosa e Ki.67 têm efeito na progressão, ao longo do tempo, desde a data do diagnóstico até à data do teste, enquanto, a variável imagem de invasão vascular tem efeito na progressão do marcador ao longo do tempo, desde a data da recidiva até à data do teste. Relativamente à progressão do marcador CEA, ao longo do tempo, desde a data do diagnóstico até à data do teste, as variáveis idade ao diagnóstico e estadio apresentam um efeito significativo. Considerando o tempo, desde a data da recidiva até à data do teste, as variáveis bilateral e estadio, têm influência na progressão deste marcador. Advisors/Committee Members: Sousa, Inês (advisor), Borges, Ana Isabel Coelho (advisor).
Subjects/Keywords: Cancro da mama; Análise de sobrevivência; Análise longitudinal; Breast cancer; Survival analysis; Longitudinal analysis
Coelho, L. R. (2017). Modelos longitudinais e de sobrevivência para a recidiva do cancro da mama . (Masters Thesis). Universidade do Minho. Retrieved from http://hdl.handle.net/1822/50030
Coelho, Liliana Rodrigues. "Modelos longitudinais e de sobrevivência para a recidiva do cancro da mama ." 2017. Masters Thesis, Universidade do Minho. Accessed January 18, 2020. http://hdl.handle.net/1822/50030.
Coelho, Liliana Rodrigues. "Modelos longitudinais e de sobrevivência para a recidiva do cancro da mama ." 2017. Web. 18 Jan 2020.
Coelho LR. Modelos longitudinais e de sobrevivência para a recidiva do cancro da mama . [Internet] [Masters thesis]. Universidade do Minho; 2017. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/1822/50030.
Coelho LR. Modelos longitudinais e de sobrevivência para a recidiva do cancro da mama . [Masters Thesis]. Universidade do Minho; 2017. Available from: http://hdl.handle.net/1822/50030
14. Ferguson, John. A Methodology for Evaluating Economic and Policy Impacts on Airline and Passenger Behavior .
Degree: 2012, George Mason University
► This dissertation describes an equilibrium model to examine domestic airline scheduling and pricing behavior in response to changes in fuel prices and runway capacity limits.… (more)
▼ This dissertation describes an equilibrium model to examine domestic airline scheduling and pricing behavior in response to changes in fuel prices and runway capacity limits. A major re-design of an equilibrium model developed by Le (2006) was performed that allows one to look at the responses of the airline industry as costs change and/or as capacity limits are altered. Part of this re-design required an analysis of the sensitivity of airfares to supply changes and the development of general elasticity models for each of the major markets served by the airports in this study. The US Government expects to spend $37 billion in order to increase airspace capacity in the US (e.g. SESAR/NextGen) while economists argue that there are market-based mechanisms that can better manage congestion at airports where expansion is impossible and during the interim before the technologies are fully functional. Those that argue against market-based approaches worry that passengers in smaller markets will lose air-transportation access, airlines are too fragile to incur any new taxes, airfares will increase and it will not force the up-gauging that will improve throughput with current technologies. By evaluating how cost changes and/or capacity changes impact airline behavior, one can evaluate if these arguments are justified. Airline domestic scheduling and pricing behavior is examined at eight congested airports (BOS, DFW, EWR, JFK, LGA, ORD, PHL, and SFO) because they generated 47.5% of the flight delays in 2007 and 42.6% of the flight delays in 2010. We record changes in the markets served by each of these airports, the frequency of service to these markets, changes in the aircraft size, the number of passengers served and the average airfares when fuel price are increased and when runway capacity limits are imposed. We also examine the effect of these changes on the profitability of the airline industry and the amount of fuel used. The results of this analysis show that: • The system is very sensitive to fuel price changes and less sensitive to capacity changes, especially between Visual Flight Rules (VFR) and Marginal Visual Flight Rules (MVFR). • The Airport Schedule Optimization Model (ASOM) developed in this dissertation indicates that the airline industry is robust but will alter their schedules and service to maintain profitability. • As fuel prices increase, airlines are likely to show greater changes in their schedules and the model reflects an increase in airfares, a decrease in passengers served and a decrease in aircraft gauge. • As fuel prices start to increase operational costs are dominated by fuel costs. When this occurs, airlines no longer see the economies of scale related to aircraft size that are exhibited at lower fuel costs. Advisors/Committee Members: Hoffman, Karla L (advisor).
Subjects/Keywords: economic analysis; performance metrics; longitudinal analysis; airport delays; market analysis; metroplex
Ferguson, J. (2012). A Methodology for Evaluating Economic and Policy Impacts on Airline and Passenger Behavior . (Thesis). George Mason University. Retrieved from http://hdl.handle.net/1920/7899
Ferguson, John. "A Methodology for Evaluating Economic and Policy Impacts on Airline and Passenger Behavior ." 2012. Thesis, George Mason University. Accessed January 18, 2020. http://hdl.handle.net/1920/7899.
Ferguson, John. "A Methodology for Evaluating Economic and Policy Impacts on Airline and Passenger Behavior ." 2012. Web. 18 Jan 2020.
Ferguson J. A Methodology for Evaluating Economic and Policy Impacts on Airline and Passenger Behavior . [Internet] [Thesis]. George Mason University; 2012. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/1920/7899.
Ferguson J. A Methodology for Evaluating Economic and Policy Impacts on Airline and Passenger Behavior . [Thesis]. George Mason University; 2012. Available from: http://hdl.handle.net/1920/7899
15. Valadas, Paulo. Projecto de uma passagem superior à autoestrada 10.
Trabalho de Projecto para obtenção do grau de Mestre em Engenharia Civil
O presente trabalho que ora se submete à apreciação e avaliação, refere-se ao… (more)
O presente trabalho que ora se submete à apreciação e avaliação, refere-se ao projecto de uma Passagem Superior em betão armado e pré-esforçado, referente ao restabelecimento de um caminho municipal rodoviário, sobre a autoestrada A10, ao Km 2+078,409, na zona do Carregado e foi realizado no âmbito do trabalho final do mestrado do curso de Engenharia Civil, do ISEL - Instituto Superior de Engenharia de Lisboa. O trabalho é composto por peças escritas e peças desenhadas. Nas peças escritas são apresentadas a descrição e a justificação do dimensionamento para cada elemento estrutural. Nas peças desenhadas são apresentados os respectivos elementos construtivos. Ao longo do documento, designado por peças escritas, são apresentados para cada elemento estrutural e por esta ordem sequencial: - o tabuleiro, os pilares e suas fundações, os encontros e suas fundações, os aparelhos de apoio e juntas de dilatação, toda a informação relevante, quer a descritiva, quer a justificativa para a solução de dimensionamento apresentado; os critérios utilizados no pré-dimensionamento das secções, modelação dos elementos estruturais e acções intervenientes, e os critérios de combinação das acções para obtenção dos esforços de cálculo e das correspondentes verificações de segurança. A análise estrutural foi efectuada através do "software" de cálculo sap2000, tendo-se modelado a estrutura com os elementos de barra, aos quais foram atribuídas características mecânicas e geométricas. Partindo dos esforços e deslocamentos obtidos, procedeu-se às verificações de segurança, com recurso a uma folha de cálculo em Excel.
The present work which hereby is submitted to evaluation refers to a prestressed concrete overpass design, referring to a road relocation at the km 2 + 078,409 A10 highway in the area of Carregado. The work was conducted in the context of the master's course in Civil Engineering, at ISEL - Instituto Superior de Engenharia de Lisboa. It is composed of written documents and drawings. In the written documents is presented the description and justification of the dimensioning for each structural element. In the drawings the respective constructive elements are presented. Throughout the document, termed written components is presented for each structural element and in the following order: - the bridge floor, the pillars and their foundations, abutments and their foundations, the bearings and expansion joints, all relevant information, that describesand justificates the dimensioning solution presented; the criteria used in the structural design, structural behavior modelling and actions combination. The structural analysis was carried out using the software SAP2000, having the structure been modeled in bar elements, to which geometrical and mechanical characteristics were assigned. With the forces and displacements obtained in the model, safety checks were carried out withExcel.
Advisors/Committee Members: Jacinto, Luciano Alberto do Carmo.
Subjects/Keywords: Passagem superior; Projecto; Análise longitudinal; Prestressed concrete overpass design; Project; Longitudinal analysis
Valadas, P. (2014). Projecto de uma passagem superior à autoestrada 10 . (Thesis). Repositório Científico do Instituto Politécnico de Lisboa. Retrieved from http://www.rcaap.pt/detail.jsp?id=oai:repositorio.ipl.pt:10400.21/4155
Valadas, Paulo. "Projecto de uma passagem superior à autoestrada 10." 2014. Thesis, Repositório Científico do Instituto Politécnico de Lisboa. Accessed January 18, 2020. http://www.rcaap.pt/detail.jsp?id=oai:repositorio.ipl.pt:10400.21/4155.
Valadas, Paulo. "Projecto de uma passagem superior à autoestrada 10." 2014. Web. 18 Jan 2020.
Valadas P. Projecto de uma passagem superior à autoestrada 10. [Internet] [Thesis]. Repositório Científico do Instituto Politécnico de Lisboa; 2014. [cited 2020 Jan 18]. Available from: http://www.rcaap.pt/detail.jsp?id=oai:repositorio.ipl.pt:10400.21/4155.
Valadas P. Projecto de uma passagem superior à autoestrada 10. [Thesis]. Repositório Científico do Instituto Politécnico de Lisboa; 2014. Available from: http://www.rcaap.pt/detail.jsp?id=oai:repositorio.ipl.pt:10400.21/4155
16. Lehman, Rebecca. The Generalized Monotone Incremental Forward Stagewise Method for Modeling Longitudinal, Clustered, and Overdispersed Count Data: Application Predicting Nuclear Bud and Micronuclei Frequencies.
Degree: PhD, Biostatistics, 2017, Virginia Commonwealth University
URL: https://scholarscompass.vcu.edu/etd/4957
► With the influx of high-dimensional data there is an immediate need for statistical methods that are able to handle situations when the number of… (more)
▼ With the influx of high-dimensional data there is an immediate need for statistical methods that are able to handle situations when the number of predictors greatly exceeds the number of samples. One such area of growth is in examining how environmental exposures to toxins impact the body long term. The cytokinesis-block micronucleus assay can measure the genotoxic effect of exposure as a count outcome. To investigate potential biomarkers, high-throughput assays that assess gene expression and methylation have been developed. It is of interest to identify biomarkers or molecular features that are associated with elevated micronuclei (MN) or nuclear bud (Nbud) frequency, measures of exposure to environmental toxins. Given our desire to model a count outcome (MN and Nbud frequency) using high-throughput genomic features as predictors, novel methods that can handle over-parameterized models need development. Overdispersion, when the variance of a count outcome is larger than its mean, is frequently observed with count response data. For situations where overdispersion is present, the negative binomial distribution is more appropriate. Furthermore, we expand the method to the longitudinal Poisson and longitudinal negative binomial settings for modeling a longitudinal or clustered outcome both when there is equidispersion and overdispersion. The method we have chosen to expand is the Generalized Monotone Incremental Forward Stagewise (GMIFS) method. We extend the GMIFS to the negative binomial distribution so it may be used to analyze a count outcome when both a high-dimensional predictor space and overdispersion are present. Our methods were compared to glmpath. We also extend the GMIFS to the longitudinal Poisson and longitudinal negative binomial distribution for analyzing a longitudinal outcome. Our methods were compared to glmmLasso and GLMMLasso. The developed methods were used to analyze two datasets, one from the Norwegian Mother and Child Cohort study and one from the breast cancer epigenomic study conducted by researchers at Virginia Commonwealth University. In both studies a count outcome measured exposure to potential genotoxins and either gene expression or high-throughput methylation data formed a high dimensional predictor space. Further, the breast cancer study was longitudinal such that outcomes and high-dimensional genomic features were collected at multiple time points during the study for each patient. Our goal is to identify biomarkers that are associated with elevated MN or NBud frequency. From the development of these methods, we hope to make available more comprehensive statistical models for analyzing count outcomes with high dimensional predictor spaces and either cross-sectional or longitudinal study designs. Advisors/Committee Members: Dr. Kellie J. Archer.
Subjects/Keywords: high-dimensional; genomics; longitudinal; Biostatistics; Longitudinal Data Analysis and Time Series; Microarrays
Lehman, R. (2017). The Generalized Monotone Incremental Forward Stagewise Method for Modeling Longitudinal, Clustered, and Overdispersed Count Data: Application Predicting Nuclear Bud and Micronuclei Frequencies . (Doctoral Dissertation). Virginia Commonwealth University. Retrieved from https://scholarscompass.vcu.edu/etd/4957
Lehman, Rebecca. "The Generalized Monotone Incremental Forward Stagewise Method for Modeling Longitudinal, Clustered, and Overdispersed Count Data: Application Predicting Nuclear Bud and Micronuclei Frequencies." 2017. Doctoral Dissertation, Virginia Commonwealth University. Accessed January 18, 2020. https://scholarscompass.vcu.edu/etd/4957.
Lehman, Rebecca. "The Generalized Monotone Incremental Forward Stagewise Method for Modeling Longitudinal, Clustered, and Overdispersed Count Data: Application Predicting Nuclear Bud and Micronuclei Frequencies." 2017. Web. 18 Jan 2020.
Lehman R. The Generalized Monotone Incremental Forward Stagewise Method for Modeling Longitudinal, Clustered, and Overdispersed Count Data: Application Predicting Nuclear Bud and Micronuclei Frequencies. [Internet] [Doctoral dissertation]. Virginia Commonwealth University; 2017. [cited 2020 Jan 18]. Available from: https://scholarscompass.vcu.edu/etd/4957.
Lehman R. The Generalized Monotone Incremental Forward Stagewise Method for Modeling Longitudinal, Clustered, and Overdispersed Count Data: Application Predicting Nuclear Bud and Micronuclei Frequencies. [Doctoral Dissertation]. Virginia Commonwealth University; 2017. Available from: https://scholarscompass.vcu.edu/etd/4957
17. Luo, Dandan. Models for Univariate and Multivariate Analysis of Longitudinal and Clustered Data.
Degree: PhD, Department of Mathematical and Statistical Sciences, 2012, University of Alberta
URL: https://era.library.ualberta.ca/files/s4655h86x
► Longitudinal studies of repeated observations on subjects are commonly undertaken in medical and biological sciences. The responses on a given occasion may be either univariate… (more)
▼ Longitudinal studies of repeated observations on subjects are commonly undertaken in medical and biological sciences. The responses on a given occasion may be either univariate or multivariate. We concentrate on three topics related to longitudinal and clustered data analysis. The first topic is the development of a class of generalized linear latent variable models. The second involves the modelling of count data with excess zeros. The third is the development of a non-Gaussian linear mixed effects model for multiple outcomes. In addressing the first problem, we propose random mean models to account for correlation among repeated measures. We extend random mean models to include mixed outcomes, renaming them random mean joint models. The difficulty in joint modelling of continuous and discrete outcomes is the lack of a natural multivariate distribution. We overcome the difficulty by introducing two cross-correlated latent processes. We apply the Monte Carlo EM (MCEM) algorithm to find the MLEs of regression coefficients and variance components, by treating the latent variables as missing data. This thesis also proposes regression models for count data with excess zeros. We solve the problem from a perspective different from that of mixture model framework. By employing the zero truncated distribution and the zero modified distribution, we establish a broad class of distributions to model data with excess zeros. We consider the zero modified Poisson regression model and zero modified binomial regression model for cross-sectional data. We extend the zero modified regression models to models with random effects. We further extend random mean models to model zero-inflated data, and formulate the corresponding zero modified random mean models. A non-Gaussian linear mixed effects model for multiple outcomes is proposed to the third question. The methodology is motivated by a glaucoma study. The normality assumption for random effects may be unrealistic, raising concerns about the validity of inferences on fixed effects and random effects if it is violated. To accommodate the skewness of the responses and the associations among multiple characteristics, we propose a mixed effects model, in which non-normal random effects are assumed by the log-gamma distribution.
Subjects/Keywords: Longitudinal Data Analysis; Zero-inflated Data; Clustered Data Analysis
Luo, D. (2012). Models for Univariate and Multivariate Analysis of Longitudinal and Clustered Data . (Doctoral Dissertation). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/s4655h86x
Luo, Dandan. "Models for Univariate and Multivariate Analysis of Longitudinal and Clustered Data." 2012. Doctoral Dissertation, University of Alberta. Accessed January 18, 2020. https://era.library.ualberta.ca/files/s4655h86x.
Luo, Dandan. "Models for Univariate and Multivariate Analysis of Longitudinal and Clustered Data." 2012. Web. 18 Jan 2020.
Luo D. Models for Univariate and Multivariate Analysis of Longitudinal and Clustered Data. [Internet] [Doctoral dissertation]. University of Alberta; 2012. [cited 2020 Jan 18]. Available from: https://era.library.ualberta.ca/files/s4655h86x.
Luo D. Models for Univariate and Multivariate Analysis of Longitudinal and Clustered Data. [Doctoral Dissertation]. University of Alberta; 2012. Available from: https://era.library.ualberta.ca/files/s4655h86x
18. Ramos, Antonio Pedro. Has Democracy Reduced Inequalities in Child Mortality? An analysis of 5 million births from 50 developing countries since 1970.
Degree: Statistics, 2013, UCLA
URL: http://www.escholarship.org/uc/item/82g9m4n1
► This dissertation is the first large scale analysis of the effects of democratization on the rich- poor gap in child mortality across the developing world.… (more)
▼ This dissertation is the first large scale analysis of the effects of democratization on the rich- poor gap in child mortality across the developing world. Theories predict that democratic institutions should help those at the bottom of the income distribution more than those at the top. Yet, previous cross-national studies on democracy and child mortality have not focused on the rich-poor gap in health outcomes. Using an unique data set with more than 5 million birth records from 50 middle and low income countries, this study is the first one to test whether those at the bottom of the income distribution benefit more from the democratic transitions than those at the top. Although the rich and poor gap in child mortality is reducing over time, this change does not seem to be driven by regime type. Yet, there is remarkable heterogeneity on the effects of democratization on health that deserves further investigation.
Subjects/Keywords: Statistics; Political Science; Demography; Child Mortality; Democracy; Longitudinal Analysis; Meta-Analysis
Ramos, A. P. (2013). Has Democracy Reduced Inequalities in Child Mortality? An analysis of 5 million births from 50 developing countries since 1970. (Thesis). UCLA. Retrieved from http://www.escholarship.org/uc/item/82g9m4n1
Ramos, Antonio Pedro. "Has Democracy Reduced Inequalities in Child Mortality? An analysis of 5 million births from 50 developing countries since 1970." 2013. Thesis, UCLA. Accessed January 18, 2020. http://www.escholarship.org/uc/item/82g9m4n1.
Ramos, Antonio Pedro. "Has Democracy Reduced Inequalities in Child Mortality? An analysis of 5 million births from 50 developing countries since 1970." 2013. Web. 18 Jan 2020.
Ramos AP. Has Democracy Reduced Inequalities in Child Mortality? An analysis of 5 million births from 50 developing countries since 1970. [Internet] [Thesis]. UCLA; 2013. [cited 2020 Jan 18]. Available from: http://www.escholarship.org/uc/item/82g9m4n1.
Ramos AP. Has Democracy Reduced Inequalities in Child Mortality? An analysis of 5 million births from 50 developing countries since 1970. [Thesis]. UCLA; 2013. Available from: http://www.escholarship.org/uc/item/82g9m4n1
19. Steffanello, Marinês. Análise longitudinal do impacto dos investimentos de tecnologia da informação na eficiência bancária à luz da metodologia DEA.
Os benefícios que a Tecnologia da Informação (TI) tem trazido à sociedade e às organizações vem aumentado ao longo do tempo. A TI tem se… (more)
Os benefícios que a Tecnologia da Informação (TI) tem trazido à sociedade e às organizações vem aumentado ao longo do tempo. A TI tem se desenvolvido com uma rapidez muito grande, prometendo ganhos de eficiência e aumentos na produtividade das empresas. Nos últimos anos, inúmeras organizações têm investido altas quantias em TI, independentemente do setor em que atuam. Dentro deste contexto, observa-se que o setor bancário tem se destacado, pois os recursos destinados para investimentos em TI crescem em ritmo acelerado. Entretanto, a falta de boas medidas quantitativas para mensurar o impacto destes investimentos na produtividade dificulta sua comprovação. Desta forma, fazem-se necessários estudos que apliquem métodos de análise temporal dos investimentos em TI, já que este tipo de investimento não apresenta resultado imediato. Buscando sanar esta lacuna, este trabalho utilizou a metodologia Análise Envoltória de Dados (DEA), que visa analisar eficiência de instituições homogêneas de forma relativa. A partir desta técnica, buscou-se analisar o efeito das variações dos investimentos em TI de um ano para outro nas variações da eficiência relativa dessas instituições em até quatro períodos seguintes ao investimento, visando identificar uma possível regularidade cíclica. Utilizou-se um banco de dados contendo treze anos de informações contábeis de 260 bancos em atuação no Brasil. Dentre as principais conclusões obtidas a partir do teste de diferenças de média, destaca-se que os aumentos dos Investimentos em TI de um ano para outro não são traduzidos em aumentos de eficiência no ano seguinte à sua realização, em nenhum dos três momentos de conversão estudados. Analisadas as defasagens temporais das variações das eficiências em dois, três e quatro anos após o incremento dos Investimentos em TI, percebeu-se que no momento de Conversão II, este foi traduzido em eficiência ao transformar Ativos em Receitas Líquidas. Já na Conversão Global, o período para reverter de forma direta, a variação dos investimentos em TI em variação de eficiência relativa, é de dois anos. A Conversão I, que representa a capacidade do banco ser competitivo, ao transformar Despesas em Ativos, não apresentou significância nos intervalos de tempo analisados no estudo.
The benefits brought by Information Technology (IT) to the society and to organizations have increased over time. IT has been developed very quickly, promising companies' increases in efficiency and productivity. Lately, many organizations have invested great sums in IT, regardless of the sector in which they operate. Within this context, the banking sector has gain a prominent position, since its resources in IT investments grow at an accelerated rhythm. However, the lack of good quantitative measures to mensurate the impact of these investments on productivity complicates its evidence. Thus, studies that apply temporal analysis methods of IT investments become necessary, since this type of investment does not show immediate results. Trying to heal this gap, this study has used the…
Advisors/Committee Members: Becker, Joao Luiz.
Subjects/Keywords: IT investment; Análise longitudinal; Tecnologia da informação; Data envelopment analysis; Investimentos; Longitudinal analysis; Eficiência; Banking efficiency; Setor bancário
Steffanello, M. (2010). Análise longitudinal do impacto dos investimentos de tecnologia da informação na eficiência bancária à luz da metodologia DEA . (Thesis). Universidade do Rio Grande do Sul. Retrieved from http://hdl.handle.net/10183/27370
Steffanello, Marinês. "Análise longitudinal do impacto dos investimentos de tecnologia da informação na eficiência bancária à luz da metodologia DEA." 2010. Thesis, Universidade do Rio Grande do Sul. Accessed January 18, 2020. http://hdl.handle.net/10183/27370.
Steffanello, Marinês. "Análise longitudinal do impacto dos investimentos de tecnologia da informação na eficiência bancária à luz da metodologia DEA." 2010. Web. 18 Jan 2020.
Steffanello M. Análise longitudinal do impacto dos investimentos de tecnologia da informação na eficiência bancária à luz da metodologia DEA. [Internet] [Thesis]. Universidade do Rio Grande do Sul; 2010. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/10183/27370.
Steffanello M. Análise longitudinal do impacto dos investimentos de tecnologia da informação na eficiência bancária à luz da metodologia DEA. [Thesis]. Universidade do Rio Grande do Sul; 2010. Available from: http://hdl.handle.net/10183/27370
20. Borges, Ana Isabel Coelho. Joint modelling of longitudinal and survival data on breast cancer .
► The main motivation of this work is to contribute to the understanding of the progression of breast cancer, within the Portuguese population, using a statistical… (more)
▼ The main motivation of this work is to contribute to the understanding of the progression of breast cancer, within the Portuguese population, using a statistical model with more complex assumptions than the traditional analysis. We aim to infer which risk factors a ect the survival of Braga's Hospital patients, diagnosed with breast tumour. While analysing risk factors that a ect two tumour markers used on the surveillance of disease progression the Carcinoma Antigen 15-3 (CA 15-3) and the Carcinoembryonic antigen (CEA). We take into account the expected association between the progressions in time of each tumour markers with patient's survival. A data set of 540 patients, along with 50 variables, was collected from medical records of the Hospital. For survival analysis it was applied the proportional hazards Cox model and the Royston-Parmar exible parametric model. General linear mixed e ects longitudinal models were used to study the progression of both tumour markers values. After conducting survival and longitudinal separate analysis, a joint modelling of these two processes to infer on the association of these was conducted, adopting the methodology of random e ects. Results from joint models, showed that the longitudinal CA-15-3 and CEA values were signi cantly associated with the survival probability of these patients. We conclude that independent analysis brings up bias parameter estimates and an assumption of association between the two processes in a joint model of breast cancer data is necessary. Advisors/Committee Members: Sousa, Inês (advisor).
Subjects/Keywords: Breast Cancer; Survival analysis; Longitudinal analysis; Joint modelling; Cancro da Mama; Análise de Sobrevivência; Análise Longitudinal; Modelos conjuntos
Borges, A. I. C. (2015). Joint modelling of longitudinal and survival data on breast cancer . (Doctoral Dissertation). Universidade do Minho. Retrieved from http://hdl.handle.net/1822/40426
Borges, Ana Isabel Coelho. "Joint modelling of longitudinal and survival data on breast cancer ." 2015. Doctoral Dissertation, Universidade do Minho. Accessed January 18, 2020. http://hdl.handle.net/1822/40426.
Borges, Ana Isabel Coelho. "Joint modelling of longitudinal and survival data on breast cancer ." 2015. Web. 18 Jan 2020.
Borges AIC. Joint modelling of longitudinal and survival data on breast cancer . [Internet] [Doctoral dissertation]. Universidade do Minho; 2015. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/1822/40426.
Borges AIC. Joint modelling of longitudinal and survival data on breast cancer . [Doctoral Dissertation]. Universidade do Minho; 2015. Available from: http://hdl.handle.net/1822/40426
University of Missouri – Columbia
21. Zhu, Liang, 1981-. Semiparametric analysis of multivariate longitudinal data.
Degree: PhD, 2008, University of Missouri – Columbia
URL: https://doi.org/10.32469/10355/6044
► [ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Longitudinal studies are conducted widely in fields such as agriculture and life sciences, business and… (more)
▼ [ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Longitudinal studies are conducted widely in fields such as agriculture and life sciences, business and industry, demography and other social sciences, medicine and public health. In longitudinal studies, individuals are measured repeatedly over time and multivariate longitudinal data occur when subjects are measured repeatedly with regard to multiple response variables. Analysis of multivariate longitudinal data can be challenging since it requires accounting for not only correlations between repeated measures of the same subject but also correlations among different response variables. One special type of longitudinal study involves monitoring subjects continuously to record occurrences of events and thus generates so-called recurrent event data. In the first part of this dissertation, we will discuss analysis of a set of multivariate longitudinal data arising from a prospective study of alcohol and drug use in college freshmen. Several statistical models and estimation approaches are presented for joint analysis of conducting alcohol and drug use. In particular, a marginal means model is proposed that leaves the correlation between response outcomes arbitrary. In the second part, regression analysis of multivariate recurrent event data with time-varying covariate effects will be considered. For the problem, we present some marginal models for the underlying counting processes and develop estimating equation based inference approaches. The asymptotic properties of the proposed estimates are established and their finite sample properties are evaluated through simulation studies. Additionally, some procedures are presented for testing the time-dependence of covariate effects and the proposed methodology is applied to sets of univariate recurrent event data and bivariate recurrent event data. The third part of this dissertation will consider variable selection for univariate and multivariate recurrent event data in the context of regression analysis. For the problem, we adopt the idea behind the nonconcave penalized likelihood approach proposed in Fan and Li (2001) and develop a nonconcave penalized estimating function approach. The proposed approach selects variables and estimates regression coefficients simultaneously and an algorithm is presented for this process. We show that the proposed approach performs as well as the oracle procedure, yielding estimates as if the correct submodel were known. Simulation studies conducted for assessing the performance of the proposed approach suggest that it works well for practical situations. The methodology is illustrated using a set of bivariate recurrent event data. Advisors/Committee Members: Sun, Jianguo, 1961- (advisor).
Subjects/Keywords: Multivariate analysis – Longitudinal studies; Regression analysis – Longitudinal studies
Zhu, Liang, 1. (2008). Semiparametric analysis of multivariate longitudinal data . (Doctoral Dissertation). University of Missouri – Columbia. Retrieved from https://doi.org/10.32469/10355/6044
Zhu, Liang, 1981-. "Semiparametric analysis of multivariate longitudinal data." 2008. Doctoral Dissertation, University of Missouri – Columbia. Accessed January 18, 2020. https://doi.org/10.32469/10355/6044.
Zhu, Liang, 1981-. "Semiparametric analysis of multivariate longitudinal data." 2008. Web. 18 Jan 2020.
Zhu, Liang 1. Semiparametric analysis of multivariate longitudinal data. [Internet] [Doctoral dissertation]. University of Missouri – Columbia; 2008. [cited 2020 Jan 18]. Available from: https://doi.org/10.32469/10355/6044.
Zhu, Liang 1. Semiparametric analysis of multivariate longitudinal data. [Doctoral Dissertation]. University of Missouri – Columbia; 2008. Available from: https://doi.org/10.32469/10355/6044
22. Kim, Min Jung. Model Specification Searches in Latent Growth Modeling: A Monte Carlo Study.
Degree: 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11147
► This dissertation investigated the optimal strategy for the model specification search in the latent growth modeling. Although developing an initial model based on the theory… (more)
▼ This dissertation investigated the optimal strategy for the model specification search in the latent growth modeling. Although developing an initial model based on the theory from prior research is favored, sometimes researchers may need to specify the starting model in the absence of theory. In this simulation study, the effectiveness of the start models in searching for the true population model was examined. The four possible start models adopted in this study were: the simplest mean and covariance structure model, the simplest mean and the most complex covariance structure model, the most complex mean and the simplest covariance structure model, and the most complex mean and covariance structure model. Six model selection criteria were used to determine the recovery of the true model: Likelihood ratio test (LRT), DeltaCFI, DeltaRMSEA, DeltaSRMR, DeltaAIC, and DeltaBIC. The results showed that specifying the most complex covariance structure (UN) with the most complex mean structure recovered the true mean trajectory most successfully with the average hit rate above 90% using the DeltaCFI, DeltaBIC, DeltaAIC, and DeltaSRMR. In searching for the true covariance structure, LRT, DeltaCFI, DeltaAIC, and DeltaBIC performed successfully regardless of the searching method with different start models. Advisors/Committee Members: Kwok, Oi-man (advisor), Willson, Victor (committee member), Yoon, Myeongsun (committee member), Taylor, Aaron (committee member).
Subjects/Keywords: Latent growth modeling; LGM; Longitudinal data analysis; Mean structure; Specification search
Kim, M. J. (2012). Model Specification Searches in Latent Growth Modeling: A Monte Carlo Study . (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11147
Kim, Min Jung. "Model Specification Searches in Latent Growth Modeling: A Monte Carlo Study." 2012. Thesis, Texas A&M University. Accessed January 18, 2020. http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11147.
Kim, Min Jung. "Model Specification Searches in Latent Growth Modeling: A Monte Carlo Study." 2012. Web. 18 Jan 2020.
Kim MJ. Model Specification Searches in Latent Growth Modeling: A Monte Carlo Study. [Internet] [Thesis]. Texas A&M University; 2012. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11147.
Kim MJ. Model Specification Searches in Latent Growth Modeling: A Monte Carlo Study. [Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11147
23. Fu, Bo. Some topics in longitudinal data analysis and panel time seriesmodels.
Degree: PhD, 2003, University of Hong Kong
URL: Fu, B. [傅博]. (2003). Some topics in longitudinal data analysis and panel time series models. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b3124416  ; http://dx.doi.org/10.5353/th_b3124416  ; http://hdl.handle.net/10722/35964
published_or_final_version
Statistics and Actuarial Science
Advisors/Committee Members: Fung, TWK, Li, WK.
Subjects/Keywords: Time-series analysis.; Longitudinal method.
Fu, B. (2003). Some topics in longitudinal data analysis and panel time seriesmodels . (Doctoral Dissertation). University of Hong Kong. Retrieved from Fu, B. [傅博]. (2003). Some topics in longitudinal data analysis and panel time series models. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b3124416 ; http://dx.doi.org/10.5353/th_b3124416 ; http://hdl.handle.net/10722/35964
Fu, Bo. "Some topics in longitudinal data analysis and panel time seriesmodels." 2003. Doctoral Dissertation, University of Hong Kong. Accessed January 18, 2020. Fu, B. [傅博]. (2003). Some topics in longitudinal data analysis and panel time series models. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b3124416 ; http://dx.doi.org/10.5353/th_b3124416 ; http://hdl.handle.net/10722/35964.
Fu, Bo. "Some topics in longitudinal data analysis and panel time seriesmodels." 2003. Web. 18 Jan 2020.
Fu B. Some topics in longitudinal data analysis and panel time seriesmodels. [Internet] [Doctoral dissertation]. University of Hong Kong; 2003. [cited 2020 Jan 18]. Available from: Fu, B. [傅博]. (2003). Some topics in longitudinal data analysis and panel time series models. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b3124416 ; http://dx.doi.org/10.5353/th_b3124416 ; http://hdl.handle.net/10722/35964.
Fu B. Some topics in longitudinal data analysis and panel time seriesmodels. [Doctoral Dissertation]. University of Hong Kong; 2003. Available from: Fu, B. [傅博]. (2003). Some topics in longitudinal data analysis and panel time series models. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b3124416 ; http://dx.doi.org/10.5353/th_b3124416 ; http://hdl.handle.net/10722/35964
24. Moore, Page Casey. A restriction method for the analysis of discrete longitudinal missing data.
Degree: Statistical Sciences., 2007, Baylor University
► Clinical trial endpoints are traditionally either physical or laboratory responses. However, such endpoints fail to reflect how patients feel or function in their daily activities.… (more)
▼ Clinical trial endpoints are traditionally either physical or laboratory responses. However, such endpoints fail to reflect how patients feel or function in their daily activities. Missing data is inevitable in most every clinical trial regardless of the amount of effort and pre-planning that originally went into a study. Many researchers often resort to ad hoc methods(e.g. case-deletion or mean imputation) when they are faced with missing data, which can lead to biased results. An alternative to these ad hoc methods is multiple imputation. Sources of missing data due to patient dropout in health related quality of life (HRQoL) studies most often result from one of the following: toxicity, disease progression, or therapeutic effectiveness. As a result, nonignorable (NMAR) missing data are the most common type of missing data found in HRQoL studies. Studies involving missing data with a NMAR mechanism are the most difficult type of data to analyze primarily for two reasons: a large number of potential models exist for these data and the hypothesis of random dropout can be neither confirmed nor repudiated. The performance of methods used for the analysis of discrete longitudinal clinical trial data considered to have a nonignorable missingness mechanism under the commonly applied restriction of monotone dropout were developed and evaluated in this dissertation. Monotone dropout, or attrition, occurs when responses are available for a patient until a certain occasion and missing for all subsequent occasions. The purpose of this study is to investigate the performance of different imputation methods available to researchers for handling the problem of missing data where the parameters of interest are six QoL assessments scheduled for collection across six equally spaced visits. We evaluate the relative effectiveness of three commonly used imputation methods, along with three restriction methods and a newly developed restriction method, through a simulation study. The new restriction method is a straightforward technique that provides superior overall performance and much higher coverage rates relative to the other methods under investigation. Advisors/Committee Members: Seaman, John Weldon, 1956- (advisor).
Subjects/Keywords: Longitudinal method.; Multivariate analysis.
Moore, P. C. (2007). A restriction method for the analysis of discrete longitudinal missing data. (Thesis). Baylor University. Retrieved from http://hdl.handle.net/2104/4880
Moore, Page Casey. "A restriction method for the analysis of discrete longitudinal missing data. " 2007. Thesis, Baylor University. Accessed January 18, 2020. http://hdl.handle.net/2104/4880.
Moore, Page Casey. "A restriction method for the analysis of discrete longitudinal missing data. " 2007. Web. 18 Jan 2020.
Moore PC. A restriction method for the analysis of discrete longitudinal missing data. [Internet] [Thesis]. Baylor University; 2007. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/2104/4880.
Moore PC. A restriction method for the analysis of discrete longitudinal missing data. [Thesis]. Baylor University; 2007. Available from: http://hdl.handle.net/2104/4880
25. Lee, Lewina Onyi. Anxiety in the second half of life: exploring trajectories and their interrelations with physical illness and stressful life events in a population-based twin sample.
Degree: PhD, Psychology, 2011, University of Southern California
URL: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/662537/rec/846
► There is limited research on late life anxiety despite the higher prevalence of anxiety disorders relative to affective disorders in older adults. This study addresses… (more)
▼ There is limited research on late life anxiety despite the higher prevalence of anxiety disorders relative to affective disorders in older adults. This study addresses gaps in the literature by examining: (1) the longitudinal course of anxiety symptoms in older age, and (2) the interrelations of anxiety with physical illness and stressful life events (SLE) in the second half of life. We investigated these associations at both phenotypic and biometric levels. ❧ This study is based on data from the Swedish Adoption/Twin Study of Aging collected over 6 occasions between 1984 and 1993. Using multilevel regression, biometric latent curve analyses, and latent change score analyses, we analyzed data from 1,576 twins who were at least 50 years old at study inclusion. Anxiety was measured using the State Trait Personality Inventory – State Anxiety subscale. A composite SLE score was created from the Social Readjustment Rating Scale. Physical illness was represented by a SUMILL variable that expressed the number of organ systems affected by reported physical illnesses. ❧ In the sample overall, anxiety followed a U-shaped trajectory over age and was characterized by significant individual differences in trajectories. Individual differences in trajectories of anxiety were nearly equally attributable to genetic and unique environmental factors. The amount of variance of anxiety followed a convex trajectory in later life, with greater variance in the middle of the age range than at either end. SLE and physical illness appeared to mediate the U-shaped trajectory of anxiety in later life, such that after adjusting for these covariates there were no clear age-related trends that were common to all participants, but significant individual variation in trajectories. We also found significant between-person differences in the degree of association between anxiety and SLE. There was no evidence of SLE or physical illness acting as a leading indicator of anxiety increases, although there was evidence for correlated trajectories and within-time correlations of anxiety with both SLE and illness. The association of anxiety with SLE was primarily mediated by individual-specific environmental factors, with a small contribution from additive genetic factors. Advisors/Committee Members: Prescott, Carol A.Gatz, Margaret (Committee Chair), Pedersen, Nancy L. (Committee Member), Crimmins, Eileen M. (Committee Member).
Subjects/Keywords: aging; anxiety; stress; genetics; longitudinal analysis; physical illness; stressful life events
Lee, L. O. (2011). Anxiety in the second half of life: exploring trajectories and their interrelations with physical illness and stressful life events in a population-based twin sample . (Doctoral Dissertation). University of Southern California. Retrieved from http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/662537/rec/846
Lee, Lewina Onyi. "Anxiety in the second half of life: exploring trajectories and their interrelations with physical illness and stressful life events in a population-based twin sample." 2011. Doctoral Dissertation, University of Southern California. Accessed January 18, 2020. http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/662537/rec/846.
Lee, Lewina Onyi. "Anxiety in the second half of life: exploring trajectories and their interrelations with physical illness and stressful life events in a population-based twin sample." 2011. Web. 18 Jan 2020.
Lee LO. Anxiety in the second half of life: exploring trajectories and their interrelations with physical illness and stressful life events in a population-based twin sample. [Internet] [Doctoral dissertation]. University of Southern California; 2011. [cited 2020 Jan 18]. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/662537/rec/846.
Lee LO. Anxiety in the second half of life: exploring trajectories and their interrelations with physical illness and stressful life events in a population-based twin sample. [Doctoral Dissertation]. University of Southern California; 2011. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/662537/rec/846
26. Shelton, Erin Dominique. A comparison of classical methods and second order latent growth models for longitudinal data analysis.
Degree: MA, Psychology, 2010, University of Southern California
► In 1988, McArdle identified issues modeling multivariate growth using what he termed "second order latent growth curve" models. Specifically, he raised questions about which type… (more)
▼ In 1988, McArdle identified issues modeling multivariate growth using what he termed "second order latent growth curve" models. Specifically, he raised questions about which type of structural equation model to use for longitudinal data analysis. For example, "Should the growth model be fit to common factors extracted from the measured variables (CUFFS)?"; or "Should a growth model be fit to the measured variables and then the intercepts and slopes of the common factors be considered (FOCUS)?" Both SEMs can be fit to the same set of data, however, as pointed ou in McArdle (1988), these two alternative models not strictly nested and therefore statistical comparison becomes more difficult. Most recent works have utilized only the CUFFS model (Ferrer, Balluerka, & Widaman, 2008; Grimm, Pianta, & Konold, 2009; Hancock, Kuo, & Lawrence, 2001; Lui, & Flay, 2009), however, because of the close relationship of the FOUCS models to the newer dynamic multivariate modeling issues (e.g., McArdle, 2008), it is an option worth further consideration.; In the examples presented by McArdle (1988), data from the Weschler Intelligence Scale for Children (WISC) were used. The longitudinal WISC dataset was completed in 1965 by R. T. Osborne (Osborne & Suddick, 1972). Children were measured on 11 subscales of the Weschler Intelligence Scale for Children (WISC). The selected sample consists of 204 children who were repeatedly measured under standardized conditions at approximate ages of 6, 7, 9, and 11. In this research, the same data and models are used but more focus is placed on the appropriate choice of SEM. Classic and contemporary techniques for analyzing repeated measures date are compared. The focus was on the specification of second order LGMs and the advantages of these methods over the more classic MANOVA and first order LGM techniques. The key results and their implications are discussed. Advisors/Committee Members: McArdle, John J. (Committee Chair), John, Richard S. (Committee Member), Wilcox, Rand R. (Committee Member).
Subjects/Keywords: growth modeling; longitudinal analysis; growth; growth curves; latent growth modeling
Shelton, E. D. (2010). A comparison of classical methods and second order latent growth models for longitudinal data analysis . (Masters Thesis). University of Southern California. Retrieved from http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/367789/rec/126
Shelton, Erin Dominique. "A comparison of classical methods and second order latent growth models for longitudinal data analysis." 2010. Masters Thesis, University of Southern California. Accessed January 18, 2020. http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/367789/rec/126.
Shelton, Erin Dominique. "A comparison of classical methods and second order latent growth models for longitudinal data analysis." 2010. Web. 18 Jan 2020.
Shelton ED. A comparison of classical methods and second order latent growth models for longitudinal data analysis. [Internet] [Masters thesis]. University of Southern California; 2010. [cited 2020 Jan 18]. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/367789/rec/126.
Shelton ED. A comparison of classical methods and second order latent growth models for longitudinal data analysis. [Masters Thesis]. University of Southern California; 2010. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/367789/rec/126
27. Modur, Sharada P. Missing Data Methods for Clustered Longitudinal Data.
Degree: PhD, Statistics, 2010, The Ohio State University
URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1274876785
► Recently medical and public health research has focused on the development of models for longitudinal studies that aim to identify individuals at risk for… (more)
▼ Recently medical and public health research has focused on the development of models for longitudinal studies that aim to identify individuals at risk for obesity by tracking childhood weight gain. The National Longitudinal Surveys of Youth 79 (NLSY79), which includes a random sample of women with biometric information on their biological children collected biennially, has been considered. A mixed model with three levels of clustered random effects has been proposed for the estimation of child-specific weight trajectories while accounting the nested structure of the dataset. Included in this model is a regression equation approach to address any remaining heterogeneity in the within-child variances. Specifically, a model has been implemented to fit the log of the within-child variances as a function of time. This allows for more flexibility in modeling residual variances that appear to be increasing over time. Using the EM algorithm with a Newton-Raphson update all the parameters of the model are estimated simultaneously. A second aspect to the research that is presented is the analysis of missing data. Extensive exploratory analysis revealed that intermittent missingness was prevalent in the relevant subset of the NLSY79 dataset. Starting with the assumptions of MCAR and MAR selection models are built up to appropriately account for the missing mechanism at play. A factorization of the multinomial distribution as a product of dependent binary observations is applied to model intermittent missingness. Logit models for dependent binary observations are used to fit selection models for missingness under the assumptions of MAR and MCAR. The NMAR case for clustered longitudinal data is discussed as an area for future research. Advisors/Committee Members: Stasny, Elizabeth (Advisor), Hans, Christopher (Advisor).
Subjects/Keywords: Statistics; Longitudinal models; multilevel models; missing data analysis
Modur, S. P. (2010). Missing Data Methods for Clustered Longitudinal Data . (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1274876785
Modur, Sharada P. "Missing Data Methods for Clustered Longitudinal Data." 2010. Doctoral Dissertation, The Ohio State University. Accessed January 18, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274876785.
Modur, Sharada P. "Missing Data Methods for Clustered Longitudinal Data." 2010. Web. 18 Jan 2020.
Modur SP. Missing Data Methods for Clustered Longitudinal Data. [Internet] [Doctoral dissertation]. The Ohio State University; 2010. [cited 2020 Jan 18]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1274876785.
Modur SP. Missing Data Methods for Clustered Longitudinal Data. [Doctoral Dissertation]. The Ohio State University; 2010. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1274876785
Universiteit Utrecht
28. Ai, W. Structural Creation of a Social Network: An Analysis of Longitudinal Development of Online Communities.
Degree: 2015, Universiteit Utrecht
URL: http://dspace.library.uu.nl:8080/handle/1874/323189
► Over the past ten years, online communities have attracted significant attention from a wide range of organizations in various markets. Social interactions within these virtual… (more)
▼ Over the past ten years, online communities have attracted significant attention from a wide range of organizations in various markets. Social interactions within these virtual communities have logged an enormous amount of digital traces, and opened up new opportunities to researchers in the field of social network studies. However, current research in this field seems mainly focused on the individual participant, while very little has been researched from a structural, time-based [longitudinal] network perspective. One of the crucial issues that comes with it, is that there is insufficient knowledge regarding the aspect of evolution in online communities. Such issues get aggravated when the data extracted from online communities are unstructured (i.e. without explicit relational references) and are cumulated over a long period of time. With this in mind, in this study we carried out a series of experiments and analysis on a public online forum [online community] with a hierarchical network structure. The objective is to identify scientific methods from existing literature for creating network structures based on unstructured data, as well as scientific approaches for longitudinal SNA. Finally, we try to determine the validity and applicability of existing literature on social network analysis in online communities from a practical point of view, in order to contribute to a scientific approach in investigating longitudinal development of online communities, from a network's perspective. As a result, we identified certain limitations in the existing literature and proposed our own methods and guidelines for social network creation and longitudinal SNA. The results of our work revealed the critical issues related to working with unstructured and longitudinal communication data retrieved from an online forum.. The analytical results of edge-ratio analysis suggest that the development of an online community can be monitored periodically based on fractions of the whole network structure (i.e. network snapshots). Indications are that the development of an online community is two-folded, i.e. participation of "old" users as well as fresh in-streams of new users is roughly equally important. Last but not least, an attempt to visualize an online community's development in a longitudinal manner with the Gephi software package has provided discernible insights, as compared to other methods. Advisors/Committee Members: Helms, R., Dalpiaz, F..
Subjects/Keywords: Online community; longitudinal development; social network analysis; unstructured data.
Ai, W. (2015). Structural Creation of a Social Network: An Analysis of Longitudinal Development of Online Communities . (Masters Thesis). Universiteit Utrecht. Retrieved from http://dspace.library.uu.nl:8080/handle/1874/323189
Ai, W. "Structural Creation of a Social Network: An Analysis of Longitudinal Development of Online Communities." 2015. Masters Thesis, Universiteit Utrecht. Accessed January 18, 2020. http://dspace.library.uu.nl:8080/handle/1874/323189.
Ai, W. "Structural Creation of a Social Network: An Analysis of Longitudinal Development of Online Communities." 2015. Web. 18 Jan 2020.
Ai W. Structural Creation of a Social Network: An Analysis of Longitudinal Development of Online Communities. [Internet] [Masters thesis]. Universiteit Utrecht; 2015. [cited 2020 Jan 18]. Available from: http://dspace.library.uu.nl:8080/handle/1874/323189.
Ai W. Structural Creation of a Social Network: An Analysis of Longitudinal Development of Online Communities. [Masters Thesis]. Universiteit Utrecht; 2015. Available from: http://dspace.library.uu.nl:8080/handle/1874/323189
29. Chu, Wanghuan. New screening procedure for ultrahigh dimensional varying-coefficient model in longitudinal data analysis.
Degree: MS, Statistics, 2015, Penn State University
URL: https://etda.libraries.psu.edu/catalog/22943
► This thesis is concerned with feature screening methods for varying-coefficient models in ultrahigh dimensional longitudinal setting. Motivated by an empirical analysis of the Childhood Asthma… (more)
▼ This thesis is concerned with feature screening methods for varying-coefficient models in ultrahigh dimensional longitudinal setting. Motivated by an empirical analysis of the Childhood Asthma Management Project, CAMP, we introduce a new screening procedure for time-varying coefficient models with ultrahigh dimensional longitudinal predictor variables. The performance of the proposed procedure is investigated via Monte Carlo simulation. Numerical comparisons indicate that it can outperform existing ones substantially, resulting in significant improvements in explained variability and prediction error. Applying these methods to CAMP, we are able to find a number of potentially important genetic mutations related to lung function, several of which exhibit interesting nonlinear patterns around puberty.
Subjects/Keywords: feature screening; varying-coefficient model; ultrahigh dimensionality; longitudinal data analysis; CAMP
Chu, W. (2015). New screening procedure for ultrahigh dimensional varying-coefficient model in longitudinal data analysis . (Masters Thesis). Penn State University. Retrieved from https://etda.libraries.psu.edu/catalog/22943
Chu, Wanghuan. "New screening procedure for ultrahigh dimensional varying-coefficient model in longitudinal data analysis." 2015. Masters Thesis, Penn State University. Accessed January 18, 2020. https://etda.libraries.psu.edu/catalog/22943.
Chu, Wanghuan. "New screening procedure for ultrahigh dimensional varying-coefficient model in longitudinal data analysis." 2015. Web. 18 Jan 2020.
Chu W. New screening procedure for ultrahigh dimensional varying-coefficient model in longitudinal data analysis. [Internet] [Masters thesis]. Penn State University; 2015. [cited 2020 Jan 18]. Available from: https://etda.libraries.psu.edu/catalog/22943.
Chu W. New screening procedure for ultrahigh dimensional varying-coefficient model in longitudinal data analysis. [Masters Thesis]. Penn State University; 2015. Available from: https://etda.libraries.psu.edu/catalog/22943
30. Liu, Siwei. Comparing Repeated-Measures ANOVA and Multilevel Growth Curve Modeling: A Simulation Study.
URL: https://etda.libraries.psu.edu/catalog/9092
► Currently in developmental research, there seems to be a trend for multilevel growth curve modeling to take the place of the classic repeated-measures ANOVA as… (more)
▼ Currently in developmental research, there seems to be a trend for multilevel growth curve modeling to take the place of the classic repeated-measures ANOVA as the first choice for analyzing longitudinal data. The preference for growth curve modeling is so strong that it is not uncommon to see researchers fit growth curve models without considering its appropriateness. This is problematic because the repeated-measures ANOVA model and the growth curve model are sub-models in the general linear mixed model family and are complementary to each other. This paper compares the two methods in analyzing simulated data that is assumed to come from a repeated-measures study with five equally spaced occasions and show a linear increase pattern. The simulation involves varying effect size, intraclass correlation size, and sample size. It is shown that repeated-measures ANOVA models generally have better fit when the error structure is selected properly. The growth curve model fits the data better only when sample size is not small and the variance of slopes is not small, even when the error structure is simulated to show a "growth curve" pattern. The results cast doubt on the popular practice of using growth curve modeling for longitudinal data without comparing the fit of different models. A general procedure of model selection is discussed.
Subjects/Keywords: Repeated-Measures ANOVA; Growth Curve Modeling; Longitudinal Data Analysis
Liu, S. (2008). Comparing Repeated-Measures ANOVA and Multilevel Growth Curve Modeling: A Simulation Study . (Masters Thesis). Penn State University. Retrieved from https://etda.libraries.psu.edu/catalog/9092
Liu, Siwei. "Comparing Repeated-Measures ANOVA and Multilevel Growth Curve Modeling: A Simulation Study." 2008. Masters Thesis, Penn State University. Accessed January 18, 2020. https://etda.libraries.psu.edu/catalog/9092.
Liu, Siwei. "Comparing Repeated-Measures ANOVA and Multilevel Growth Curve Modeling: A Simulation Study." 2008. Web. 18 Jan 2020.
Liu S. Comparing Repeated-Measures ANOVA and Multilevel Growth Curve Modeling: A Simulation Study. [Internet] [Masters thesis]. Penn State University; 2008. [cited 2020 Jan 18]. Available from: https://etda.libraries.psu.edu/catalog/9092.
Liu S. Comparing Repeated-Measures ANOVA and Multilevel Growth Curve Modeling: A Simulation Study. [Masters Thesis]. Penn State University; 2008. Available from: https://etda.libraries.psu.edu/catalog/9092