The present study investigates the nature of communicative language ability as manifested in performance on the TOEFL iBT® test, as well as the relationship between this ability with test-takers' study-abroad and learning experiences. The research interest in the nature of language ability is shared by the language testing community, whereas understanding the factors that affect language acquisition has been a focus of attention in the field of second language acquisition (Bachman & Cohen, 1998). This study utilizes a structural equation modeling approach, a hybrid of factor analysis and path analysis, to address issues at the interface between language testing and second language acquisition. The purpose of this study is two-fold. The first has a linguistic focus: to provide empirical evidence to enhance our understanding of the nature of communicative language ability by examining the dimensionality of this construct in both its absolute and relative senses. The second purpose, which has a social and cultural orientation, is to investigate the possible educational, social, and cultural influences on the acquisition of English as a foreign language, and the relationships between test performance and test-taker characteristics. The results revealed that the ability measured by the test was predominantly skill-oriented. The role of the context of language use in defining communicative language ability could not be confirmed due to a lack of empirical evidence. As elicited by the test, this ability was found to have equivalent underlying representations in two groups of test-takers with different context-of-learning experiences. The common belief in the superiority of the study-abroad environment over learning in the home country could not be upheld. Furthermore, both study-abroad and home-country learning were proved to have significant associations with aspects of the language ability, although the results also suggested that variables other than the ones specified in the models may have had an impact on the development of the ability being investigated. From a test validation point of view, the results of this study provide crucial validity evidence regarding the test's internal structure, this structure's generalizability across subgroups of test-takers, as well as its external relationships with relevant test-taker characteristics. Such a validity inquiry contributes to our understanding of what constitutes the test construct, and how this construct interacts with the individual and socio-cultural variables of foreign language learners and test-takers.

Travel demand analysis has traditionally focused on exploring and modeling travel behavior on weekdays. This emphasis on weekday travel behavior analysis was largely motivated by the presence of well-defined peak periods, primarily associated with the journey to and from work. Most travel demand models are based on weekday travel characteristics and purport to estimate traffic volumes for daily or peak weekday conditions. Much of the planning and policy making that occurs in transportation arena in response to weekday travel behavior and forecasts. More recently, there had been a growing interest in exploring, understanding, and quantifying weekend travel characteristics. The ability to do this has been limited due to the non-availability of travel survey data that includes weekend trip information. Most travel surveys collect information about weekday travel behavior and ignore weekend days. However, the 2001 National Household Travel Survey includes a substantial sample that provided detailed trip information for weekend days and therefore this dataset offers a key opportunity to explore in-depth weekend travel characteristics. Weekend travel behavior is expected to be substantially different from the weekday travel behavior for difference in several spatial and temporal constraints. The difference in constraints can also lead to a change in trip chaining patterns on weekdays and weekends. Differences in constraints coupled with socio-economic changes characterized by greater disposable income, time-constrained lives, and greater discretionary activity opportunities point towards the growing role that weekend travel behavior is going to play in transportation planning and policy-making. This thesis provides a comprehensive analysis of weekend travel behavior using the 2001 NHTS. Differences and similarities between weekday and weekend travel behavior are identified and presented for different urban areas sizes varying according to Metropolitan Statistical Area (MSA) size. Models of weekend and weekday travel behavior are developed to capture the structural relationship of socio-demographics, activity durations, and travel duration are developed using structural equations modeling approaches to better understand the relationships among these aspects of travel behavior on weekdays and weekends. This report is supposed to act as an updated data guide to the National Cooperative Highway Research Program's (NCHRP) Report 365 titled "Travel Estimation Techniques for Urban Planning" aims at studying the changes in behavioral characteristics between two categories of the day of week - a weekday and a weekend based on personal, household and trip characteristics.

The Student Risk Screening Scale—Internalizing/Externalizing (SRSS-IE) was developed to screen elementary-aged students for Emotional and Behavioral Disorders (EBD). Its use has been extended to middle schools with little evidence that it measures the same constructs as in elementary schools. Scores of a middle school population from the SRSS-IE are analyzed with Multilevel Confirmatory Factor Analysis (MCFA) to examine its factor structure, factorial invariance between females and males, and its reliability. Several MCFA models are specified, and compared, with two retained for further analysis. The first model is a single-level model with chi-square and standard errors adjusted for the clustered nature of the data. The second model is a two-level model. Both support the hypothesized structure found in elementary populations of two factors (Externalizing and Internalizing). All items load on only one factor except Peer Rejection, which loads on both. Reliability is estimated for both models using several methods, which result in reliability coefficients ranging between .89-.98. Both models also show evidence of Configural, Metric, and Scalar invariance between females and males. While more research is needed to provide other kinds of evidence of validity in middle school populations, results from this study indicate that the SRSS-IE is an effective screening tool for EBD.

This study focuses on the interrelationships between risky sexual practices, substance use, and arrest history. The sample consists of 948 newly arrested juvenile offenders processed at a centralized intake facility in 2006. A series of confirmatory factor analysis and structural equation modeling techniques are used to 1) determine if risky sexual behavior, marijuana and cocaine use, and arrest history form a unidimensional latent factor, 2) examine the direct effect of age on the latent factor, and 3) compare the factor structure, as well as the effect of age on the latent factor, across four demographic subgroups based on race and gender. Results provide moderate support for all three research objectives. Important similarities, as well as differences, in the factor structure across the four groups were found. The prevention and intervention implications of the findings, limitations of the current study, and directions for future research are discussed.

ABSTRACT When depressive illness has its onset during adolescence it can exert a profound negative influence upon the individual and their daily functioning. Early identification of young people at risk of, or already experiencing, depressive symptoms is critical to enabling targeted intervention from clinicians, including occupational therapists. Early identification, however, is hampered by an incomplete understanding of how the disorder manifests in the daily lives of adolescents. The mental health determinants and sequelae of engagement in everyday activities represent core concerns of occupational therapists. As part of therapy with adolescents in Child and Youth Mental Health Services (CYMHS), occupational therapists endeavour to improve health by assessing time use, and engaging in interventions which explicitly target involvement in daily activity. Notwithstanding current practice, evidence for a link between actual time use and depressive symptom severity is scant. Background and Research Aims In this thesis the time use of adolescents is explored and related to depressive symptom severity in a series of three cross sectional studies. In keeping with ecologically- and occupation-focussed theoretical models of health and adolescent development (Bronfenbrenner & Morris, 2006; Poulsen & Ziviani, 2004; World Health Organization, 2002), a novel approach to the study of time use has been taken. The studies quantify the amount of time that adolescents are exposed to the various conditions inherent in activities and their ecological settings. In conceptualising time use as ‘exposure’, attention is drawn specifically to common affordances of activities. In this thesis these are described as ‘underlying dimensions’ of time use. Key underlying dimensions of interest include (a) ‘physical exertion’ in daily time use, (b) time spent with different social partners, and (c) time engaged in structured activities. The studies make use of cumulative estimates of time use by summing each episode of exposure to the underlying dimensions of time use, across the out-of-school hours. This research was conducted with the aims of (a) aiding early identification of adolescents who are vulnerable to depressive illness, (b) examining the evidence for the assessment of time use in CYMHS, (c) identifying aspects of adolescent time use which are appropriate targets for occupational therapists’ intervention, and (d) directing future research into the effectiveness of time use-focussed interventions offered by occupational therapists to adolescents who are vulnerable to depressive illness. Methodology and Study Findings All the studies involve secondary analysis of interview and time diary data collected from a nationally representative sample of approximately 730 adolescents (13-18 years) participating in the Panel Study of Income Dynamics Child Development Supplement II. Data were gathered in 2002/2003 by the Institute of Social Research at the University of Michigan in America. Studies 1 and 2 employ ordinal logistic regression analyses to separately explore two of the underlying dimensions of time use, namely the physical exertion in daily activity, and the time spent engaged in activity alone or with key social partners (including parents, siblings and friends). These studies indicate that time devoted to physical activity of moderate to vigorous intensity does not predict depressive symptom severity, breadth of participation in sporting extracurricular activity may be protective against depressive illness for males. For both genders, factors related to the positive or negative aspects of social relationships (such as adolescents’ ratings of how close they felt to parents, and the extent of risky behaviour among friends) appear to be stronger predictors of depressive symptomatology than the actual amount of time engaged in activity with others. Study 3 is informed conceptually and methodologically by the findings of Studies 1 and 2, and uses structural equation modeling, to examine a complex multivariate model of time use and depressive symptoms. This model incorporates a large range of factors which are theorized to influence the qualitative experience of spending time in a given context (e.g., adolescents’ perceptions of friend acceptance, which may influence the psychological impact of a prolonged encounter with friends). Study 3 reveals that the quantity of time over the course of a weekday or weekend day that adolescents are exposed to different types of activity (e.g., structured extracurricular activity, shared activity with parents) has no direct association with depressive symptom severity. However, an indirect path is identified, whereby the amount of time devoted to joint activity with parents is linked with depressive symptom severity via adolescent perceptions of parent acceptance. Conclusions and Recommendations The studies of this thesis have shown that the conceptualisation and quantification of time use as cumulative exposure to some specific underlying dimensions of engagement, are of little direct assistance in identifying young people who are vulnerable to depressive illness, however, this information may inform a range of clinical practices for occupational therapists working in CYMHS. Information on time use is therefore worth gathering in such services, particularly when it provides insights into social contact. It has been clearly and consistently identified that time use and its links with depression cannot be fully appreciated without considering the nature of adolescents’ relationships with their social partners in time use. Findings indicate that when time spent engaged in joint activity with parents is scant, or when poor relationships with parents are reported, adolescents at risk of depression are likely to benefit from therapy which is directed towards enhancing the quantity and quality of parent-adolescent interactions. The significance of this research lies in the generation of evidence to support further research into time use and its implications for mental health. Greater support for the specialist role of occupational therapists in addressing time use concerns will be gained through future studies which explore the immediate affective experience of spending time in activity, the personal and environmental contextual factors which mediate these experiences, and the implications of such experiences for mental health. Further to the insights gained regarding time use and depressive illness, the thesis presents an approach to research (i.e., a secondary analysis) and research methodologies which may be used by occupational therapists to answer complex questions regarding occupational engagement across the lifespan. Keywords: Adolescence, Depression, Internalizing Disorder, Time Use, Time Diary, Physical Activity, Social Contexts, Structured Extracurricular Activity, Organised Activity, Structural Equation Modeling. Australian and New Zealand Standard Research Classifications (ANZSRC): 111714 Mental Health 100%.

Incentive for this research stems from the fact that Business-to-Consumer electronic commerce sector is going to oligopoly and the new actors have relatively less chance to accomplish in the current market if they follow the same ways that the old companies have already paved. Considering this challenge, the aim is to understand the adoption process of customers by analyzing the contemporary perceptions of individuals against e-shopping. Initially, business-to-consumer electronic commerce adoption model is developed. Proposed model and hypotheses are tested with Partial Least Squares as a Structural Equation Modeling technique using data collected from 1115 respondents via an online survey. Then, semi-structured open-ended interviews are conducted in order to grasp the perceptions of customers. The results are interpreted following a systematic mixed methodology involving Interpretative Phenomenological Analysis to elucidate the antecedents and causal relations of constructs in an inductive and exploratory way to illuminate a socio-technical phenomenon as complementary to deductive and confirmatory quantitative perspective. Findings and implications are asserted to be utilized as a roadmap especially for start-up companies that challenge to survive and succeed in current market conditions. Trust is found to be the predominant factor in e-shopping adoption. It is proved that, after almost two decades shopping via Internet had been invented, contemporarily, definitions for the dimensions of Enjoyment, Perceived Usefulness, Store Familiarity, Perceived Ease of Use and Subjective Norm have evolved into new semantics and customers perceive each factor according to their actual cognition contexts.

The purpose of this doctoral thesis research study was first to investigate the needs for a faculty development program in Middle East Technical University (METU). Later, in the second phase, models that explained the linear structural relationships among factors that might be influential on faculty&amp / #146 / s perceived competencies about the skills necessary for the instructional practices, personal, professional and organizational developments were proposed and compared. In this study, a questionnaire considering different aspects of faculty developments were sent to all of the academicians in METU. After collecting data from faculty members and research assistants, they were analyzed both descriptively and using principal component factor analysis. Based on the results of factor analysis, linear structural relations models fitting the data were generated through LISREL-SIMPLIS computer program runs. The descriptive results indicated that there was a feeling for need to improve the faculty&#039 / s self-proficiency in different instructional issues. On the other hand, both descriptive results and LISREL modeling results indicated that faculty members and research assistants show different characteristics based on their needs and factors affecting their self-proficiencies. These aspects will lead us to prepare different faculty development programs based on their needs and priorities. The result for both faculty members and research assistants showed that in a faculty, instructional self-proficiency cannot be considered as a single absolute parameter. Rather, it should be considered as several interrelated parameters connected to different aspects of faculty&#039 / s proficiencies.

Conventional statistical methods assuming data sampled under simple random sampling are inadequate for use on complex survey data with a multilevel structure and non-independent observations. In structural equation modeling (SEM) framework, a researcher can either use the ad-hoc robust sandwich standard error estimators to correct the standard error estimates (Design-based approach) or perform multilevel analysis to model the multilevel data structure (Model-based approach) to analyze dependent data. In a cross-sectional setting, the first study aims to examine the differences between the design-based single-level confirmatory factor analysis (CFA) and the model-based multilevel CFA for model fit test statistics/fit indices, and estimates of the fixed and random effects with corresponding statistical inference when analyzing multilevel data. Several design factors were considered, including: cluster number, cluster size, intra-class correlation, and the structure equality of the between-/within-level models. The performance of a maximum modeling strategy with the saturated higher-level and true lower-level model was also examined. Simulation study showed that the design-based approach provided adequate results only under equal between/within structures. However, in the unequal between/within structure scenarios, the design-based approach produced biased fixed and random effect estimates. Maximum modeling generated consistent and unbiased within-level model parameter estimates across three different scenarios. Multilevel latent growth curve modeling (MLGCM) is a versatile tool to analyze the repeated measure sampled from a multi-stage sampling. However, researchers often adopt latent growth curve models (LGCM) without considering the multilevel structure. This second study examined the influences of different model specifications on the model fit test statistics/fit indices, between/within-level regression coefficient and random effect estimates and mean structures. Simulation suggested that design-based MLGCM incorporating the higher-level covariates produces consistent parameter estimates and statistical inferences comparable to those from the model-based MLGCM and maintain adequate statistical power even with small cluster number.

The aim of the current study is to investigate the role of social-cognitive (locus of control, rumination and socially-prescribed perfectionism), emotional (shame and guilt), and behavioral (conciliatory behaviors) reactions toward oneself in predicting self-forgiveness based on Hall and Fincham&rsquo / s (2005) theoretical model. The sample of this study was composed of 815 (445 female, 370 male) university students attending five different faculty programs at Middle East Technical University (METU). Heartland Forgiveness Scale, Trait Shame and Guilt Scale, Socially-Prescribed Perfectionism Scale, Ruminative Response Scale, The Internal-External Locus of Control Scale and Demographic Information Form were used in data collection. In the current study, structural equation modeling (SEM) was used primarily to test the hypothesized model, integrating the effects of the social-cognitive (locus of control, rumination and socially-prescribed perfectionism), emotional (shame and guilt), and behavioral (conciliatory behaviors) variables as determinants of self-forgiveness. The SEM results indicated that this model provided a good fit to the data in spite of three non-significant paths, including the direct paths from (a) socially-prescribed perfectionism to shame and guilt and (b) locus of control to self-forgiveness. Since some paths appeared to be non-significant, the hypothesized model was trimmed. The result of the trimmed model was surpassed many of the criteria for good fit. Overall, the total variance explained by the finalized model in self-forgiveness was .32.

The purpose of this study is twofold: (1) to examine the effects of knowledge on cognition and regulation of cognition on declarative knowledge, conditional knowledge, and procedural knowledge in geometry and (2) to examine the interrelationships among declarative knowledge, conditional knowledge, and procedural knowledge in geometry. The reciprocal relationships between metacognitive and knowledge factors were modeled by using data from tenth grade secondary school students. Structural equation modeling was used to test the hypothesized relationships of two metacognitive factors (knowledge of cognition, regulation of cognition) and three knowledge factors (declarative knowledge, conditional knowledge, procedural knowledge). The observed variables representing the latent variables were determined by carrying out exploratory factor analysis and confirmatory factor analysis for the metacognitive awareness inventory and geometry knowledge test separately. Major findings revealed: (1) Declarative knowledge significantly and positively influences conditional and procedural knowledge / (2) Procedural knowledge has a signitificant and positive direct effect on conditional knowledge / (3) Declarative knowledge has a positive indirect effect on conditional knowledge / (4) Knowledge of cognition significantly and positively influences procedural knowledge / (5) Regulation of cognition has a significant but negative direct effect on procedural knowledge / (6) Knowledge of cognition has positive indirect effects on conditional and procedural knowledge / (7) Regulation of cognition has negative indirect effects on conditional and procedural knowledge / (8) Knowledge of cognition and regulation of cognition have non-significant direct effect on declarative and conditional knowledge. The results showed that knowledge of cognition has the strongest direct effect on procedural knowledge and the direct effect of declarative knowledge on conditional knowledge is stronger than on procedural knowledge. In view of the findings considerable suggestions is provided for teachers, instructional designers, and mathematics education researchers.