Cited by 452Statistical Methods in Clinical TrialsStatistical Methods in EpidemiologyMeta-analysis and systematic reviews

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Sample Size Estimation in Clinical Research

Wang, Xiaofeng, Ji, Xinge·2020·Chest

DOI 10.1016/j.chest.2020.03.010

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Abstract

Sample size determination is an essential step in planning a clinical study. It is critical to understand that different study designs need different methods of sample size estimation. Although there is a vast literature discussing sample size estimation, incorrect or improper formulas continue to be applied. This article reviews basic statistical concepts in sample size estimation, discusses statistical considerations in the choice of a sample size for randomized controlled trials and observational studies, and provides strategies for reducing sample size when planning a study. To assist clinical researchers in performing sample size calculations, we have developed an online calculator for common clinical study designs. The calculator is available at http://riskcalc.org:3838/samplesize/. Finally, we offer our recommendations on reporting sample size determination in clinical studies.

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“To examine the internal consistency, the Cronbach’s alpha values were described as poor, moderate, good, and excellent, with rates of > 0.50, 0.50-0.75, 0.75-0.90, and ≤ 0.90, respectively (Tavakol et al., 2011; George et al., 2003; Wang and Ji, 2020).”
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“Using the sample size calculation formula and referring to Fundamentals of Sample Size Estimation in Clinical Research [37,38], with a significance level of a = 0.05 (2-tailed) and a statistical power of 1 - b = 0.8 ( b = 0.2), the required sample size per group was calculated to be 26 participants.”
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“A two-sided Pearson’s chi-squared test with α = 0.05 and 80% statistical power indicated that at least 130 participants were required in each group [18,19].”
Influential

Authors: Wang, X., & Ji, X.
Affiliations: Cleveland Clinic (US)
Corresponding author: Wang, Xiaofeng
ORCID: Wang, Xiaofeng
Venue: Chest
Publisher: Elsevier BV
Published: 2020-07
Volume: 158
Issue: 1
Pages: S12-S20
ISSN: 0012-3692 (ISSN-L)
DOI: 10.1016/j.chest.2020.03.010
OpenAlex: W3039422431
Cited by: 452
References: 0
Citations by year: 2026: 87 · 2025: 105 · 2024: 121 · 2023: 76 · 2022: 36 · 2021: 22 · 2020: 4
FWCI: 24.19
Type: journal article
Language: en
Open access: closed
Licence: www.elsevier.com/tdm/userlicense/1.0/ (tdm)
www.elsevier.com/legal/tdmrep-license (tdm)
Locations: CHEST Journal (publishedVersion)
PubMed (publishedVersion)
Topics: Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Clinical Trials
Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Epidemiology
Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
Keywords: sample size determination, randomized controlled trials, observational studies, clinical research design, statistical power
MeSH terms: Humans, Research Design, Randomized Controlled Trials as Topic, Sample Size, Observational Studies as Topic

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Sample Size Estimation in Clinical Research

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