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Table 1 Different ways to describe 'risk'

From: Clinical review: How is risk defined in high-risk surgical patient management?

Placebo arm (n = 1000) Treatment arm (n = 1000) Relative risk reduction Absolute risk reduction Number needed to treat
200 100 50 10 10
20 10 50 1 100
2 1 50 0.1 1000
  1. In this example, a treatment trial involving 2000 patients, 'relative risk reduction' remains the same while 'absolute risk reduction' and 'number needed to treat' show differences in the appreciation of risk as the success of the treatment is modelled to change.