Cited by 102Statistical Methods in Clinical TrialsStatistical Methods in EpidemiologyMeta-analysis and systematic reviews

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Underpowering in randomized trials reporting a sample size calculation

Vickers, Andrew J·2003·Journal of Clinical Epidemiology

DOI 10.1016/s0895-4356(03)00141-0

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Abstract

Objective The objective of this study was to determine whether standard deviations (SDs) used in sample size calculations are smaller than those found in the resulting study sample, thereby leading to underpowered studies.Method The predicted SD used in the sample size calculation and the actual SD of the study sample were recorded for randomized trials recently published in one of four major journals.Results Sample SD was greater than predicted SD for 80% of endpoints. About one quarter of trials required five times as many patients as specified in the sample size calculation.Conclusion Trials reporting sample size calculations for continuous endpoints published in the most reputable medical journals are often underpowered. There seems to be insufficient understanding that the SD of a sample of patients is a random variable, associated with imprecision, that cannot easily be extrapolated from one population to another.

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Ward, E. S., King, M., Lloyd, M., Bower, P., Sibbald, B., Farrelly, S., Gabbay, M., Tarrier, N., & Addington-Hall, J. M. (2000) · BMJ · doi:10.1136/bmj.321.7273.1383 · Cited by 271
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Authors: Vickers, A. J.
Affiliations: Memorial Sloan Kettering Cancer Center (US)
Corresponding author: Vickers, Andrew J
ORCID: Vickers, Andrew J
Venue: Journal of Clinical Epidemiology
Publisher: Elsevier BV
Published: 2003-08
Volume: 56
Issue: 8
Pages: 717-720
ISSN: 0895-4356 (ISSN-L)
DOI: 10.1016/s0895-4356(03)00141-0
OpenAlex: W1999562241
Cited by: 102
References: 16
Citations by year: 2026: 3 · 2025: 5 · 2024: 6 · 2023: 1 · 2022: 3 · 2021: 4 · 2020: 4 · 2019: 1 · 2018: 6 · 2017: 4 · 2016: 7 · 2015: 6 · 2014: 7 · 2013: 10 · 2012: 3
FWCI: 5.16
Type: journal article
Language: en
Open access: closed
Licence: www.elsevier.com/tdm/userlicense/1.0/ (tdm)
Locations: Journal of Clinical Epidemiology (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: underpowered trials, sample size determination, standard deviation, statistical power, continuous outcomes, trial reporting
MeSH terms: Data Interpretation, Statistical, Humans, Randomized Controlled Trials as Topic, Sample Size

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Underpowering in randomized trials reporting a sample size calculation

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