This dissertation consists of three manuscripts. The manuscripts contribute to a budding "methodological reform" currently taking place in quantitative second-language (L2) research. In the first manuscript, the researcher describes an empirical investigation on the application of two well-known effect size estimators, eta-squared (eta…

Research Findings: In Study 1, we observed 32 Chinese kindergarteners playing a number board game with their caregivers in dyads. Number board game playing provided important opportunities for kindergarteners and their caregivers to talk about an array of number concepts, but their numeracy-related exchanges rarely went beyond counting. In Study…

Purpose: Because walking is highly recommended for prevention and treatment of obesity and some of its biomechanical aspects are not clearly understood for overweight people, we compared the absolute and normalized ground reaction forces (GRF), plantar pressures, and temporal parameters of normal-weight and overweight participants during…

Problem Statement: A number of recent studies on constructivism that have been conducted separately (independently) have arrived at very different results. Throughout the ten-year period in which the constructivist approach has been applied, there have been studies that have researched the effect of the newly-introduced approach on student…

This study used a randomized controlled trial design to investigate the ROOTS curriculum, a 50-lesson kindergarten mathematics intervention. Ten ROOTS-eligible students per classroom (n = 60) were randomly assigned to one of three conditions: a ROOTS five-student group, a ROOTS two-student group, and a no-treatment control group. Two primary…

Despite considerable interest in research and practice in the effect of classroom disciplinary climate of schools on academic achievement, little is known about the generalizability of this effect over countries. Using hierarchical linear analyses, the present study reveals that a better classroom disciplinary climate in a school is significantly…

The Rasch model, a member of a larger group of models within item response theory, is widely used in empirical studies. Detection of uniform differential item functioning (DIF) within the Rasch model typically employs null hypothesis testing with a concomitant consideration of effect size (e.g., signed area [SA]). Parametric equivalence between…

One of the vexing problems in the analysis of SSD is in the assessment of the effect of intervention. Serial dependence notwithstanding, the linear model approach that has been advanced involves, in general, the fitting of regression lines (or curves) to the set of observations within each phase of the design and comparing the parameters of these…

The purpose of this document is to describe the methods RAND used to analyze achievement for 23 personalized learning (PL) schools for the 2012-13 through 2013-14 academic years. This work was performed at the request of the Bill & Melinda Gates Foundation (BMGF), as part of a multi-year evaluation contract. The 23 schools were selected from a…

Often researchers face situations where comparative studies between two or more programs are necessary to make causal inferences for informed policy decision-making. Experimental designs employing randomization provide the strongest evidence for causal inferences. However, many pragmatic and ethical challenges may preclude the use of randomized…

Fragile X syndrome (FXS) is a well-described inherited cause of intellectual disability and the most common known genetic cause of autism. Social deficits in girls with FXS are not well understood. To better understand barriers to social functioning that may contribute to mental health outcomes, we administered a theoretically based social…

This article proposes an innovative approach to estimating the counterfactual without the necessity of generating information from either a control group or a before-measure. Building on the idea that program participants are capable of estimating the hypothetical state they would be in had they not participated, the basics of the Roy-Rubin model…

This study explored the effects of an evidence-based literacy program, ABRACADABRA, on the spelling abilities of children with autism spectrum disorder (ASD). Twenty children with ASD aged 5-11 years were assigned to matched instruction and waitlist control groups. Children in the instruction group received 26 hrs of individualized, home-based…

The current study aims to examine the effect of interactive e-books on students' achievement at Najran University in computer in education course. Quasi-experimental study design is used in the study and to collect data the researchers built achievement test to measure the dependent variable represented in the achievement affected by experimental…

This study examined the effects of differential grading in science, technology, engineering, and mathematics (STEM) and non-STEM fields over eight consecutive semesters. Using data from 62,122 students at 26 four-year postsecondary institutions, students were subdivided by institutional admission selectivity levels, gender, and student major…