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Table 1 Simulated scenarios for sample size determination in the design of a hypothetical study

From: Delta inflation: a bias in the design of randomized controlled trials in critical care medicine

  Standard Scenario Relaxed significance level Relaxed Power Baseline Mortality shifted away from 50% Inflated delta
Significance level (two-sided) 0.05 0.1 0.05 0.05 0.05
Power 90% 90% 80% 90% 90%
Baseline (placebo) mortality rate 50% 50% 50% 40% 50%
Delta (ARR) 10% 10% 10% 10% 15%
Required sample size 1076 884 816 992 480
  1. Inflation of delta has a substantially larger impact on required sample size than changes in the other variables. ARR, absolute risk reduction.