| 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. | |
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MedLine Citation:
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PMID: 355881 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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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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Authors:
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J A Freiman; T C Chalmers; H Smith; R R Kuebler |
Publication Detail:
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Type: Clinical Trial; Journal Article; Randomized Controlled Trial |
Journal Detail:
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Title: The New England journal of medicine Volume: 299 ISSN: 0028-4793 ISO Abbreviation: N. Engl. J. Med. Publication Date: 1978 Sep |
Date Detail:
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Created Date: 1978-10-27 Completed Date: 1978-10-27 Revised Date: 2007-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0255562 Medline TA: N Engl J Med Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 690-4 Citation Subset: AIM; IM |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Clinical Trials as Topic Humans Probability Research* Research Design* Therapeutics |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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