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September 1981

Statistical Proof in Inconclusive 'Negative' Trials

Author Affiliations

From the Department of Mathematical Sciences, University of Akron (Ohio) (Dr Reed); and the Department of Higher Education, University of Denver (Dr Slaichert).

Arch Intern Med. 1981;141(10):1307-1310. doi:10.1001/archinte.1981.00340100063016

Three hundred thirty-five published articles from six medical journals that contained "negative" results were examined to determine the probability of detecting "small," "medium," and "large" therapeutic improvements. The mean probability of detecting a small effect size was.138; for a medium effect size, the probability was.387; and for a large effect size, it was.614.

(Arch Intern Med 1981;141-1307-1310)