Given limited resources, schools are encouraged to consider not only what works, but also at what cost. Cost-effectiveness analysis offers a formal methodology to conceptualize and calculate the ratio of the costs to implement an intervention to its effects (i.e., incremental cost-effectiveness ratios). This study used the ingredients method to analyze secondary data from a randomized controlled trial (N = 537 fourth- and fifth-grade students) to calculate the cost-effectiveness of a classwide math intervention, and provides an overview of cost-effectiveness analysis for readers unfamiliar with the formal methodology. For fourth-graders, the incremental cost-effectiveness ratio was $169.07, indicating it cost $169.07 per student for a 1 standard deviation increase in scaled scores on the state assessment. For fifth-graders, there was no statistically significant effect on the state assessment, but there were improvements in curriculum-based measurement (CBM) scores with incremental cost-effectiveness ratios ranging from $65.08 to $469.12, depending on the type of CBM probe and implementation context. Additionally, using number-needed-to-treat (i.e., the number of participants who must be provided with the intervention to prevent one failure on the state assessment), the cost was $126.90 to prevent failure on the state assessment for one fourth-grade student receiving special education services or for one student who scored below the 25th percentile on the prior year's state assessment. Implications and directions for future research are discussed.

鉴于资源有限，我们鼓励学校不仅要考虑什么可行，还要考虑成本。成本效益分析提供了一种正式的方法来概念化和计算实施干预措施的成本与其效果的比率（即增量成本效益比率）。本研究使用成分法分析随机对照试验的二级数据 ( N = 537 名四年级和五年级学生）来计算全班数学干预的成本效益，并为不熟悉正式方法的读者提供成本效益分析的概述。对于四年级学生，增量成本效益比为 169.07 美元，表明州评估的比例分数增加 1 个标准差，每位学生的成本为 169.07 美元。对于五年级学生，对州评估没有统计上的显着影响，但基于课程的测量 (CBM) 分数有所提高，增量成本效益比从 65.08 美元到 469.12 美元不等，具体取决于 CBM 探索和实施的类型语境。此外，使用需要治疗的人数（即，必须接受干预以防止一次州评估失败的参与者人数），为防止一名接受特殊教育服务的四年级学生或一名得分低于上一年状态评估的第 25 个百分位。讨论了未来研究的意义和方向。