Mediation analyses are crucial for understanding the mechanisms through which interventions or theoretical constructs influence outcomes within nested structures, commonly found in education, psychology, and sociology. Recognizing the importance of these effects, designing and analyzing robust studies to detect them is essential. This dissertation…

Latent change score (LCS) models are a powerful class of structural equation modeling that allows researchers to work with latent difference scores that minimize measurement error. LCS models define change as a function of prior status, which makes it well-suited for modeling developmental theories or processes. In LCS models, like other latent…

Mixed methods research collects, analyzes, and integrates rigorous qualitative and quantitative methods to gain a deeper understanding of a phenomenon than would be gained by using either method alone. Integration is one of the key features of mixed methods research and consists of mixing qualitative and quantitative research in a systematic way…

The present meta-analytic study examined the overall effectiveness of child-centered play therapy (CCPT) and child-parent relationship therapy (CPRT) for children experiencing internalizing problems. After conducting a comprehensive literature search and review, 25 studies published between 2000 and 2023 met the following inclusion criteria: (a)…

Understanding when it is appropriate to make causal inferences from a statistical result is a fundamental skill for science literacy. Prior research has concentrated on erroneous causal judgments about observational studies, but there is little research on whether people understand that experiments provide stronger justification for causal claims.…

In Single-Case Designs (SCD), the outcome variable most commonly involves some form of count data. However, statistical analyses and associated effect size (ES) calculations for count outcomes have only recently been proposed. Three recently proposed ES methods for count data are: Nonlinear Bayesian effect size (Rindskopf, 2014), Log Response…

Applied researchers faced with limited resources can utilize planned missing designs by incorporating missing data into their research design to collect more and higher quality data compared to a conventional experimental design. Two-method measurement planned missing designs (TMM-PMD) are a type of planned missing design whereby researchers…

Once research questions are posed, researchers must answer many a priori questions regarding research design before analysis can be performed and any conclusions can be made, including sample selection criteria, data collection method, model specification, analysis and estimation technique. The choices made by researchers along this forking path…

The purpose of this study was to investigate the effectiveness of four different models (bifactor, CTC(M-1), CTCU and unidimensional) as to optimal model selection when the wording effect associated with negatively worded items was present. A Monte Carlo simulation study was conducted to compare model-data fit and accuracy in parameter estimates…

The purpose of this dissertation is to develop principles and strategies for and identify limitations of multisite cluster randomized trials in the context of partially and fully nested designs. In the first study, I develop principles of estimation, sampling variability, and inference for studies that leverage multisite designs within the context…

This study utilizes a correlational research design to identify the relationship, if any, between institutional and external support of research and development (R&D) at an R1 University Carnegie Classification of Institutions of Higher Education R1: Very High Research Activity Doctoral University in the southeastern United States of America.…

The Q-matrix played a key role in implementations of diagnostic classification models (DCMs) or cognitive diagnostic models (CDMs) -- a family of psychometric models that are gaining attention in providing diagnostic information on students' mastery of cognitive attributes or skills. Using two Monte Carlo simulation studies, this dissertation…

Missing data is a common challenge to any researcher in almost any field of research. In particular, human participants in research do not always respond or return for assessments leaving the researcher to rely on missing data methods. The most common methods (i.e., Multiple Imputation and Full Information Maximum Likelihood) assume that the…

This study introduces a novel approach for conducting Systematic Literature Reviews(SLRs) by incorporating a unique mixed-methods design into the well-established SLR process. The proposed approach, identified as Mixed-Methods Based Systematic Literature Review (MMB-SLR), not only provides researchers with a broader perspective on their research…

The purpose of this descriptive study was to investigate course-based undergraduate research experience (CURE) outcomes of community college students by looking at students' sense of project ownership, science self-efficacy, and science identity using an end of course survey. A total of 54 students, 41 females and 13 males, completed the survey.…