Cluster Randomized Trial (CRT) designs are inherently multilevel and reflect the hierarchical structure of schools and the wider education system. To capture this multilevel nature, CRTs are commonly analysed using multilevel (or hierarchical) linear models. It is fairly common for CRT designs and analyses to include school and individual/pupil…

We develop a theoretical and empirical basis for the design of teacher professional development studies. We build on previous work by (a) developing estimates of intraclass correlation coefficients for teacher outcomes using two- and three-level data structures, (b) developing estimates of the variance explained by covariates, and (c) modifying…

Designing, developing, and implementing a multi-year randomized control trial targeting what works in gifted education mathematics study is challenging, at best. In response to the United States Department of Education's Institute of Education Sciences request for proposal, we carefully constructed a mixed-methods study by assembling a diverse…