“…Next, the following covariates were added to the model: (a) percentage of CEC quality indicators met as a continuous variable; (b) measure of transfer (i.e., proximal = 1, distal = 0); (c) dosage in sessions as a continuous variable; (d) implementer of intervention (i.e., researcher = 1, teacher = 0); (e) size of instructional group (i.e., small group = 1, large group = 0); (f) grade-level (i.e., elementary = 1, secondary = 0); (f) use of length models (i.e., yes = 1, no = 0); and (g) research design (i.e., group design = 1, SCRD = 0). These covariates were chosen a priori due to having previously moderated overall effect sizes of mathematics interventions (i.e., dosage [Stevens et al, 2018]; implementer [Lei et al, 2020]; grouping [Dennis, Sharp, et al, 2016]; research design [Ennis & Losinski, 2019a]; grade level [Dennis, Sharp, et al, 2016;Dennis, Knight, et al, 2016]). The use of length models was selected as a covariate based on the What Works Clearinghouse (WWC) practice guide for improving fraction performance (Siegler et al, 2011) and the notion that length models emphasize magnitude, a foundational concept for constructing rational number understanding (Fennel & Karp, 2017;Siegler, 2016;Van Hoof et al, 2018;Woodward, 2017).…”