Figure 2.

Number needed to treat: how many patients do we have to treat to prevent respiratory distress syndrome in one baby?

• Baseline risk or control event rate = 24%
• RR × Baseline risk = experimental event rate = 0.6 × 24 = 14%
• Absolute risk difference = 24 – 14 = 10%
• NNT = (1/10) × 100 = 10