The Power of the Test for Treatment Effects in Three-Level Block Randomized Designs
The Power of the Test for Treatment Effects in Three-Level Block Randomized Designs
复制标题
三水平区组随机设计中治疗效果检验的威力
DOI：
10.1080/19345740802328216
复制
发表时间：
2008
影响因子：
1.8
通讯作者：
S. Konstantopoulos
中科院分区：
文献类型：
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作者：
S. Konstantopoulos
摘要 涉及嵌套结构的实验可以将处理条件分配给子组（例如教室）或子组内的个人（例如学生）。此类实验的设计需要了解类内相关结构，以计算达到足够功效来检测治疗效果所需的样本量。本研究提供了三级块随机平衡设计（具有两级嵌套）的计算能力方法，例如，学生嵌套在教室内，教室嵌套在学校内。功效计算考虑了第二级（教室）和第三级（学校）的嵌套效应、样本量效应（例如，1 级、2 级和 3 级单元的数量）和协变量效应（例如，预处理措施）。这些方法可推广到检查结果的群体差异的准实验研究。
Abstract Experiments that involve nested structures may assign treatment conditions either to subgroups (such as classrooms) or individuals within subgroups (such as students). The design of such experiments requires knowledge of the intraclass correlation structure to compute the sample sizes necessary to achieve adequate power to detect the treatment effect. This study provides methods for computing power in three-level block randomized balanced designs (with two levels of nesting) where, for example, students are nested within classrooms and classrooms are nested within schools. The power computations take into account nesting effects at the second (classroom) and at the third (school) level, sample size effects (e.g., number of level-1, level-2, and level-3 units), and covariate effects (e.g., pretreatment measures). The methods are generalizable to quasi-experimental studies that examine group differences on an outcome.