Cited by 428Statistical Methods in EpidemiologyStatistical Methods in Clinical TrialsMeta-analysis and systematic reviews

Statistics in Brief: The Importance of Sample Size in the Planning and Interpretation of Medical Research

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Biau, David Jean, Kernéis, Solen, Porcher, Raphaël·2008·Clinical Orthopaedics and Related Research

Abstract

The increasing volume of research by the medical community often leads to increasing numbers of contradictory findings and conclusions. Although the differences observed may represent true differences, the results also may differ because of sampling variability as all studies are performed on a limited number of specimens or patients. When planning a study reporting differences among groups of patients or describing some variable in a single group, sample size should be considered because it allows the researcher to control for the risk of reporting a false-negative finding (Type II error) or to estimate the precision his or her experiment will yield. Equally important, readers of medical journals should understand sample size because such understanding is essential to interpret the relevance of a finding with regard to their own patients. At the time of planning, the investigator must establish (1) a justifiable level of statistical significance, (2) the chances of detecting a difference of given magnitude between the groups compared, ie, the power, (3) this targeted difference (ie, effect size), and (4) the variability of the data (for quantitative data). We believe correct planning of experiments is an ethical issue of concern to the entire community.

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  1. Pearson ES, Neyman J. On the use, interpretation of certain test criteria for purposes of statistical inference: Part II. Biometrika. 1928;20A:263-294.
  2. Sterne JA, Davey Smith G. Sifting the evidence: what's wrong with significance tests? BMJ. 2001;322:226-231.

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Authors
Biau, D. J., Kernéis, S., & Porcher, R.
Affiliations
Inserm (FR)
Corresponding author
Biau, David Jean
Venue
Clinical Orthopaedics and Related Research
Published
2008-06-20
Volume
466
Issue
9
Pages
2282-2288
ISSN
  • 0009-921X (ISSN-L)
  • 1528-1132
OpenAlex
W2061128187
Cited by
428
References
39
Citations by year
2026: 35 · 2025: 62 · 2024: 32 · 2023: 34 · 2022: 43 · 2021: 50 · 2020: 54 · 2019: 25 · 2018: 23 · 2017: 18 · 2016: 13 · 2015: 8 · 2014: 5 · 2013: 8 · 2012: 3
FWCI
4.72
Type
journal article
Language
en
Open access
Locations
  • Clinical Orthopaedics and Related Research (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Epidemiology
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Clinical Trials
  • Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
Keywords
sample size, statistical power, type II error, effect size, sampling variability, study design planning, statistical significance, research ethics
MeSH terms
Confidence Intervals, Odds Ratio, Sample Size, Biomedical Research

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