This study examined whether the efficacy of ROOTS, a 50-lesson mathematics intervention program focused on whole number concepts for at-risk kindergarten students, differed by group size and whether initial skill moderated intervention effects by group size. The study utilized a randomized block design with at-risk students (n = 1,251) within classrooms (n = 138) randomly assigned to one of two treatment conditions (a small group of two or five students) or the control condition. Proximal and distal measures were collected in the fall (pretest), spring (posttest), and winter of first grade (follow-up). Results indicated that students who participated in ROOTS performed better at posttest than control students (Hedges’s g from 0.09 to 0.81), that impact did not vary by group size, and that initial skill moderated the impact of ROOTS compared with control student outcomes but likely was not due to differences in group size.

中文翻译：

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通过小组规模和初始技能检查幼儿园数学干预的有效性

这项研究检验了 ROOTS（一个 50 课时的数学干预计划，侧重于有风险的幼儿园学生的整数概念）的功效是否因小组规模而异，以及初始技能是否会因小组规模而调节干预效果。该研究采用随机区组设计，教室 (n = 138) 内有风险的学生 (n = 1,251) 被随机分配到两种治疗条件之一（由两个或五个学生组成的小组）或对照条件。在一年级的秋季（前测）、春季（后测）和冬季（后续）收集了近端和远端测量值。结果表明，参加 ROOTS 的学生在后测中的表现优于对照组（Hedges 的 g 从 0.09 到 0.81），这种影响不受小组规模的影响，