Confidence Intervals Assess Both Clinical Significance and Statistical Significance

Editorials15 March 1991Confidence Intervals Assess Both Clinical Significance and Statistical SignificanceLeonard E. Brahman, PhDLeonard E. Brahman, PhDAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-114-6-515 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptInvestigators sometimes base their claim of superiority for a new treatment over older treatments on statistical significance (Pvalues) without stressing whether there is a real clinical advantage. Not all statistically significant differences are clinically significant (1-3). Fortunately, confidence intervals can address both clinical and statistical significance (1).Annals(4-6) and other journals (1, 7-11) recommend using confidence intervals in reporting the main results of studies. In this editorial, I use hypothetical examples to illustrate point estimates and confidence intervals of the difference between the percentages of patients responding to two treatments for a cancer. These examples show how confidence...References1. Berry G. Statistical significance and confidence intervals Editorial. Med J Austr. 1986;144:618-9. CrossrefMedlineGoogle Scholar2. Sackett D, Haynes R, and Tugwell P. Clinical Epidemiology—A Basic Science for Clinical Medicine. Boston: Little, Brown 1985. Google Scholar3. Levitt S, Boen J, and Potish R. Rebuttal to letter entitled "Clinical trials: statistical significance and clinical importance." Int J Radiation Oncology Biol Phys. 1981;7:1741-2. CrossrefMedlineGoogle Scholar4. Simon R. Confidence intervals for reporting results of clinical trials. Ann Intern Med. 1986;105:429-35. LinkGoogle Scholar5. Rothman K. Significance questing. Ann Intern Med. 1986;105:445-7. LinkGoogle Scholar6. Braitman L. 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