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Published on: September 11, 2021
Tips for troublesome sample-size calculation
Junyong In1, Hyun Kang2, Jong Hae Kim3
1Department of Anesthesiology and Pain Medicine, Dongguk University Ilsan Hospital, Goyang, Korea.
Abstract:
Properly set sample size is one of the important factors for scientific and persuasive research. The sample size that can guarantee both clinically significant differences and adequate power in the phenomena of interest to the investigator, without causing excessive financial or medical considerations, will always be the object of concern. In this paper, we reviewed the essential factors for sample size calculation. We described the primary endpoints that are the main concern of the study and the basis for calculating sample size, the statistics used to analyze the primary endpoints, type I error and power, the effect size and the rationale. It also included a method of calculating the adjusted sample size considering the dropout rate inevitably occurring during the research. Finally, examples regarding sample size calculation that are appropriately and incorrectly described in the published papers are presented with explanations.
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