Early childhood education and family involvement have been shown to provide a positive impact on students' academic achievement regardless of socioeconomic circumstances and background. They have been regarded as two of the most important protective factors in maximizing outcomes for children at risk, especially those from low-income backgrounds. The overall objective of this study was to examine how family involvement changes over time, whether it predicted cognitive outcomes for preschool populations, and potential variables that mediate the relationship between family involvement and outcomes. Data from the Head Start Impact Study conducted through the Department of Health and Human Services (DHHS) were used to answer the research questions. Exploratory and Confirmatory analysis revealed three dimensions of home involvement based on survey items: involvement related to literacy, numeracy, and family resources. Growth curve models suggested increased levels of involvement as children progressed from preschool to first grade. Higher levels of involvement for Literacy for observed for children in Head Start during the first data collection follow-up. The types of involvement were significantly related to cognitive scores as measured by the PPVT-III and WJ-III Achievement. Parenting styles acted as a mediator between involvement and cognitive outcomes. Implications for policy and practice related to transition services are discussed. / School Psychology

Veterinarians often perform controlled experiments in which they inoculate animals with infectious diseases. They then monitor the transmission process in infected animals. The aim of such experiments can be to assess vaccine effects. The fitting of individual-level models (ILMs) to the infectious disease data, typically achieved by means of Markov Chain Monte Carlo (MCMC) methods, can be computationally burdensome. Here, we want to see if a vaccination effect can be identified using simpler regression-type models rather than the complex infectious disease models. We examine the use of various logistic growth curve models, via a series of simulated experiments in which the underlying true model is a mechanistic model of infectious disease spread. We want to investigate whether a vaccination effect can be identified when only partial epidemic curves are observed, and to assess the performance of these models when experiments are run with various sets of observational times.

<p><strong>Background:</strong> Developmental neuroscience research suggests that relative differences in emerging social skills between very young children with ASD may influence the trajectories of multiple important developmental domains, such as language ability. Such “cascade” associations between developmental trajectories may contribute in important ways to the substantial heterogeneity in symptoms and functioning seen in children with ASD. However, longitudinal research has yet to test such “cascade” models of change in children diagnosed with ASD.</p> <p><strong>Objectives:</strong> In this dissertation I aimed to model cascade patterns of association between social competence and language ability pathways in the year after diagnosis of ASD in preschool-aged children. Data for 365 participants aged 2-4 years old who had been recently diagnosed with ASD and followed prospectively were obtained from the “Pathways To Better Outcomes in ASD Study”.</p> <p><strong>Methods:</strong> Study 1 aimed to determine whether social competence and structural language ability could be measured as distinct constructs that were invariant over time and between clinically relevant groups of young children with ASD. Study 2 modeled longitudinal reciprocal associations between these domains. Study 3 addressed the issue of variability and change within this sample, and tested whether baseline levels and rate of change in one domain were associated with subsequent growth in the other.</p> <p><strong>Results:</strong> Social competence and language ability constructs were measurably distinct and invariant in a young sample comprising verbal and non-verbal children with ASD. Only small reciprocal cascade effects were evident between social and language pathways. Levels of social competence at time of diagnosis were significantly associated with subsequent language growth.</p> <p><strong>Conclusions:</strong> In preschoolers with ASD, advantages in social competence as measured at time of diagnosis appear to “spill over” in a feed-forward cascade model to influence progress in language ability. Social competence and language ability then appear to develop along more specialized, less interrelated pathways.</p> / Doctor of Philosophy (PhD)