Cluster randomized trials involving participants nested within intact treatment and control groups are commonly performed in various educational, psychological, and biomedical studies. However, recruiting and retaining intact groups present various practical, financial, and logistical challenges to evaluators and often, cluster randomized trials…

Over the last decade, there has been a steady increase in the number of Indigenous graduate research students in Australia, yet research and pedagogy has not kept pace with changes underway in the sector. From an extensive search of literature published between 2000 and 2017, 15 papers (representing 10 research projects conducted by seven teams or…

The purpose of this synthesis of literature was to identify and analyze existing research that used experimental or quasi-experimental design in school-based agricultural education. This study utilized published articles in the "Journal of Agricultural Education" from the years 2006 through 2016. The study identified 35 articles that met…

There is much debate over the number of interviews needed to reach data saturation for themes and metathemes in qualitative research. The primary purpose of this study is to determine the number of interviews needed to reach data saturation for metathemes in multisited and cross-cultural research. The analysis is based on a cross-cultural study on…

A key consideration in planning studies of community-based HIV education programs is identifying a sample size large enough to ensure a reasonable probability of detecting program effects if they exist. Sufficient sample sizes for community- or group-based designs are proportional to the correlation or similarity of individuals within communities.…

Purpose: Composite measures of children's use of tense and agreement morphology differ in their emphasis on accuracy, diversity, or productivity, yet little is known about how these different measures change over time. An understanding of these differences is especially important for the study of children with specific language impairment, given…

This study examined the performance of a proposed iterative Wald approach for detecting differential item functioning (DIF) between two groups when preknowledge of anchor items is absent. The iterative approach utilizes the Wald-2 approach to identify anchor items and then iteratively tests for DIF items with the Wald-1 approach. Monte Carlo…

This article provides a brief introduction to the Rasch model. Motivation for using Rasch analyses is provided. Important Rasch model concepts and key aspects of result interpretation are introduced, with major points reinforced using a simulation demonstration. Concrete guidelines are provided regarding sample size and the evaluation of items.

Multisite trials, which are being used with increasing frequency in education and evaluation research, provide an exciting opportunity for learning about how the effects of interventions or programs are distributed across sites. In particular, these studies can produce rigorous estimates of a cross-site mean effect of program assignment…

Designs that facilitate inferences concerning both the total and indirect effects of a treatment potentially offer a more holistic description of interventions because they can complement "what works" questions with the comprehensive study of the causal connections implied by substantive theories. Mapping the sensitivity of designs to…

High dimensional multivariate data, where the number of variables approaches or exceeds the sample size, is an increasingly common occurrence for social scientists. Several tools exist for dealing with such data in the context of univariate regression, including regularization methods such as Lasso, Elastic net, Ridge Regression, as well as the…

Recently Watkins, Bargagliotti, and Franklin (2014) discovered that simulations of the sampling distribution of the mean can mislead students into concluding that the mean of the sampling distribution of the mean depends on sample size. This potential error arises from the fact that the mean of a simulated sampling distribution will tend to be…

This study presents a systematic review of previous research on ebook-based language learning. E-book-based language learning has been increasingly investigated in the field of language education, whereas previous review studies of relevant literature were relatively low in volume and incomprehensive from aspects of research participants and…

Statistics is enjoying some well-deserved limelight across mathematics curricula of late. Some statistical concepts, however, are not especially intuitive, and students struggle to comprehend and apply them. As an AP Statistics teacher, the author appreciates the central limit theorem as a foundational concept that plays a crucial role in…

This paper aims to illustrate how data visualization could be utilized to identify errors prior to modeling, using an example with multi-dimensional item response theory (MIRT). MIRT combines item response theory and factor analysis to identify a psychometric model that investigates two or more latent traits. While it may seem convenient to…