Cited by 1,628Statistical Methods in Clinical TrialsStatistical Methods in EpidemiologyMeta-analysis and systematic reviews

The Importance of Beta, the Type II Error and Sample Size in the Design and Interpretation of the Randomized Control Trial: Survey of 71 Negative Trials

Freiman, Jennie A., Chalmers, Thomas C., Smith, Harry, Kuebler, Roy R.·1978·New England Journal of Medicine

Abstract

Seventy-one "negative" randomized control trials were re-examined to determine if the investigators had studied large enough samples to give a high probability (greater than 0.90) of detecting a 25 per cent and 50 per cent therapeutic improvement in the response. Sixty-seven of the trials had a greater than 10 per cent risk of missing a true 25 per cent therapeutic improvement, and with the same risk, 50 of the trials could have missed a 50 per cent improvement. Estimates of 90 per cent confidence intervals for the true improvement in each trial showed that in 57 of these "negative" trials, a potential 25 per cent improvement was possible, and 34 of the trials showed a potential 50 per cent improvement. Many of the therapies labeled as "no different from control" in trials using inadequate samples have not received a fair test. Concern for the probability of missing an important therapeutic improvement because of small sample sizes deserves more attention in the planning of clinical trials.

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Crossref · 10.1056/nejm197809282991304

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  • Considering limited resources and budget, sample size calculation and power analysis may require a trade-off between cost-effectiveness and power.

    “For this reason, considering limited resources and budget, sample size calculation and power analysis may require a trade-off between cost-effectiveness and power [3,4].”

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Authors
Freiman, J. A., Chalmers, T. C., Smith, H., & Kuebler, R. R.
Venue
New England Journal of Medicine
Published
1978-09-28
Volume
299
Issue
13
Pages
690-694
ISSN
  • 0028-4793 (ISSN-L)
  • 1533-4406
OpenAlex
W1970046651
Cited by
1,628
References
5
Citations by year
2026: 8 · 2025: 11 · 2024: 14 · 2023: 14 · 2022: 13 · 2021: 30 · 2020: 14 · 2019: 22 · 2018: 52 · 2017: 22 · 2016: 25 · 2015: 24 · 2014: 22 · 2013: 30 · 2012: 30
FWCI
61.86
Type
journal article
Language
en
Open access
closed
Locations
  • New England Journal of Medicine (publishedVersion)
  • PubMed (publishedVersion)
  • DigitalGeorgetown (Georgetown University Library) (submittedVersion)
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
type II error, sample size, randomized controlled trials, negative trial results, statistical power, confidence intervals, clinical trial design, trial interpretation
MeSH terms
Clinical Trials as Topic, Humans, Probability, Research, Research Design, Therapeutics

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