Using the number needed to treat in clinical practice

Arch Phys Med Rehabil. 2004 Oct;85(10):1729-31. doi: 10.1016/j.apmr.2004.03.025.


The number needed to treat (NNT) is gaining attention as a method of reporting the results of clinical trails with dichotomous outcome measures. The NNT is defined as the number of patients who would need to be treated, on average, with a specific intervention to prevent 1 additional bad outcome or to achieve 1 desirable outcome in a given time period. Because it reports outcomes in terms of patient numbers, it is extremely useful to clinicians for making decisions about the effort expended with a particular intervention to achieve a single positive outcome. This special communication describes the NNT statistic and its utility for choosing clinical interventions.

MeSH terms

  • Clinical Trials as Topic / methods
  • Confidence Intervals*
  • Data Interpretation, Statistical
  • Humans
  • Research Design
  • Risk Assessment
  • Sample Size*