In randomized control trials (RCT), the recent focus has shifted to how an intervention yields positive results on its intended outcome. This aligns with the recent push of implementation science in healthcare (Bauer et al., 2015) but goes beyond this. RCTs have moved to evaluating the theoretical framing of the intervention as well as differing…

Virtual education in the United States continues to be a popular option for K-12 students. The enrollment in full-time virtual schools not only represents typical learners but a growing number of students with disabilities, including low-incidence disabilities. In some states, this population exceeds the state-wide average percentage of students…

Propensity score matching is a relatively new technique used in observational studies to approximate data that have been randomly assigned to treatment. This technique assimilates the values of several covariates into a single propensity score that is used as a matching variable to create similar groups. This dissertation comprises two separate…

In educational research, a randomized controlled trial is the best design to eliminate potential selection bias in a sample to support valid causal inferences, but it is not always possible in educational research because of financial, ethical, and logistical constrains. One alternative solution is use of the propensity score (PS) methods.…

This dissertation comprises three papers that propose, discuss, and illustrate models to make improved inferences about research questions regarding student achievement in education. Addressing the types of questions common in educational research today requires three different "extensions" to traditional educational assessment: (1)…

When researchers are unable to randomly assign students to treatment conditions, selection bias is introduced into the estimates of treatment effects. Random assignment to treatment conditions, which has historically been the scientific benchmark for causal inference, is often impossible or unethical to implement in educational systems. For…

Despite the increasing popularity of latent class models (LCM) in educational research, methodological studies have not yet accumulated much information on the appropriate application of this modeling technique, especially with regard to requirement on sample size and number of indicators. This dissertation study represented an initial attempt to…

A simulation study was conducted to evaluate the performance of three tests of mediation: the bias-corrected and accelerated bootstrap (Efron & Tibshirani, 1993), the asymmetric confidence limits test (MacKinnon, 2008), and a multiple regression approach described by Kenny, Kashy, and Bolger (1998). The evolution of these methods is reviewed and…

Despite the speed at which Second Life has been adopted by universities and schools to teach courses, little educational research and theory addresses this multiplayer online "world." This case study explored undergraduate university instructors' teaching methods and tools within a virtual environment. It also considered whether instructors are…