title: Sample size considerations when groups are the appropriate unit of analysis.
abstract: This article discusses issues to be considered by nurse researchers when groups should be used as the unit of randomization. Advantages and disadvantages are presented, with statistical calculations needed to determine the effective sample size. Examples of these concepts are presented using data from the Black Cosmetologists Promoting Health Program. Different hypothetical scenarios and their impact on sample size are also presented. Given the complexity of calculating the sample size when using groups as the unit of randomization, it is advantageous for researchers to work closely with statisticians when designing and implementing studies that anticipate the use of groups as the unit of randomization.
authors: School of Medicine, University of California, San Diego, La Jolla, CA 92093-0623, USA. gsadler@ucsd.edu
authors: Georgia Robins
authors: GR
authors: Sadler
authors: Celine Marie
authors: CM
authors: Ko
authors: Jennifer
authors: J
authors: Alisangco
authors: Bradley P
authors: BP
authors: Rosbrook
authors: Eric
authors: E
authors: Miller
authors: Judith
authors: J
authors: Fullerton
mesh_terms: D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D012494:Sampling Studies
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