Executive functions (EFs)--the higher level cognitive abilities that enable us to control our own thoughts and actions--continue to develop into early adulthood, yet no longitudinal study has examined their stability during the important life transition from late adolescence to young adulthood. In this twin study (total N = 840 individuals from…

We assessed potential factors associated with "current" or "ever" self-injurious behaviors, reported in the Autism Diagnostic Interview-Revised, among children with autism spectrum disorder (n = 692) from the Study to Explore Early Development. Data on factors examined were obtained from questionnaires, standardized clinical…

Through a secondary analysis of statewide data from Colorado, people with intellectual and related developmental disabilities (ID/DD) were classified into five clusters based on their support needs characteristics using cluster analysis techniques. Prior latent factor models of support needs in the field of ID/DD were examined to investigate the…

This study investigates whether age-related changes in the structure of 5 complex working memory (WM) tasks (a) reflect a general or domain specific system, (b) follows a similar trajectory across different age spans, and (c) contribute domain general or domain specific resources to achievement measures. The study parsed the sample (N = 2,471)…

Digital technologies have revolutionized the way people acquire information and gain new knowledge. With a click or touch on the screen, anybody who is online can sail in the digital world and accomplish many things. As such, the optimal use of information and communication technology involves user comprehension, knowledge, and awareness of…

Background: Cluster randomized experiments that assign intact groups such as schools or school districts to treatment conditions are increasingly common in educational research. Such experiments are inherently multilevel designs whose sensitivity (statistical power and precision of estimates) depends on the variance decomposition across levels.…

In response to calls for reform in undergraduate biology education, we conducted research examining how varying active-learning strategies impacted students' conceptual understanding, attitudes, and motivation in two sections of a large-lecture introductory cell and molecular biology course. Using a quasi-experimental design, we collected…

This study leveraged the complementary nature of confirmatory factor (CFA), item response theory (IRT), and latent class (LCA) analyses to strengthen the rigor and sophistication of evaluation of two new measures of the Air Force Academy's "leader of character" definition--the Character Mosaic Virtues (CMV) and the Leadership Mosaic…

Previous research has demonstrated that first-generation college students are less likely to persist to their sophomore year than non-first-generation students (Davis, 2010; Choy, 2001). The first six weeks has been identified as a critical time for adjustment and integration to college (Tinto, 1987; Astin, 1993; Woosley, 2003, 2009). Although…

Interdistrict open enrollment is the nation's largest and most widespread school choice program, but our knowledge of these programs is limited. Drawing on 5 years of student-level data from the universe of public school attendees in Colorado, we perform a three-stage analysis to examine the dynamics of student participation in the state's…

This dissertation uses a case-sensitive approach to examine an active travel intervention's diverse target population. It builds on a series of travel choice models, and draws key conceptual themes from Chapin's (1974) human activity model, which highlights opportunity-related and propensity-related factors associated with behaviors. The research…

Background: Cluster-randomized experiments that assign intact groups such as schools or school districts to treatment conditions are increasingly common in educational research. Such experiments are inherently multilevel designs whose sensitivity (statistical power and precision of estimates) depends on the variance decomposition across levels.…

The genetic factor structure of a range of learning measures was explored in twin children, recruited in preschool and followed to Grade 2 ("N"?=?2,084). Measures of orthographic learning and word reading were included in the analyses to determine how these patterned with the learning processes. An exploratory factor analysis of the…

Americans change residences frequently. Residential mobility can reflect positive changes in a family's circumstances or be a symptom of instability and insecurity. Mobility may also change neighborhoods as a whole. To shed light on these challenges, this report uses a unique survey conducted for the "Making Connections" initiative. The…

This paper presents the results of an investigation into the issue of statewide tax and expenditure limitations (TELs). Through the use of public opinion surveys and case studies of the campaigns, the author explains the politics of the TEL issue. Chapter 1 uses a multivariate analysis to determine whether or not differences exist in the voting…