Choosing inclusion criteria that minimize the time and cost of clinical trials

Figure 4 Numbers of patients screened and enrolled in a model study of heterogeneous responders having a statistically significant positive result. For this model the proportion of type 1, good responders q = 0.2, the response probability for type 1 patients, π₁ = 1.0, the response probability for type 2, poor responders, π₂ = 0. The response probabilities for both phenotypes to the control treatment, π₃ and π₄ both equal 0.2. The mean value of the z statistic for the alternative hypothesis is 2.96 (84% power for the trial). The proportion of patients, α, assigned to the experimental group is 0.5.