Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 1998 Nov 7;317(7168):1309-12.
doi: 10.1136/bmj.317.7168.1309.

Confidence intervals for the number needed to treat

D G Altman  1
Affiliations
Review

Confidence intervals for the number needed to treat

D G Altman. BMJ. .
No abstract available

PubMed Disclaimer

Figures

Figure 1
Figure 1
95% confidence interval for NNT=10
Figure 2
Figure 2
Relation between the absolute risk reduction (ARR) and number needed to treat and their confidence intervals (NNTB=number needed to treat (benefit); NNTH=number needed to treat (harm)) for the same example as in figure 1
Figure 3
Figure 3
Forest plot for meta-analysis of data from eight randomised trials comparing bypass surgery with coronary angioplasty in relation to angina in one year. A number needed to treat (benefit) (NNTB) for coronary artery bypass grafting and its 95% confidence interval for each trial and for the overall estimate is shown
Figure 4
Figure 4
Summaries of meta-analyses of trials of prophylactic antiemetics in surgery for strabismus in children, showing the number needed to treat (benefit) (NNTB) value (95% confidence interval, NNTB to ∞ to number needed to harm (NNTH)) for each drug. (From Tramèr et al 11)
See this image and copyright information in PMC

Comment in

References

    1. Cook RJ, Sackett DL. The number needed to treat: a clinically useful measure of treatment effect. BMJ. 1995;310:452–454. - PMC - PubMed
    1. Daly LE. Confidence limits made easy: interval estimation using a substitution method. Am J Epidemiol. 1998;147:783–790. - PubMed
    1. McQuay HJ, Moore RA. Using numerical results from systematic reviews in clinical practice. Ann Intern Med. 1997;126:712–720. - PubMed
    1. Sackett DL, Richardson WS, Rosenberg W, Haynes RB. Evidence-based medicine. How to practice and teach EBM. London: Churchill-Livingstone; 1997. p. 208.
    1. Altman DG, Gore SM, Gardner MJ, Pocock SJ. Statistical guidelines for contributors to medical journals. In: Gardner MJ, Altman DG, editors. Statistics with confidence. London: BMJ; 1989. pp. 83–100. - PMC - PubMed