Figure 2.

Treatment for gastric cancer. Hypothetical results are shown for A = radical gastrectomy / splenectomy, B = "simple" gastrectomy, and C = radiation. In the sequential study, results for B and C differ in the first trial (when 30% of the subjects receive effective supportive care), and results for A and B are similar in the second trial (when 70% of the subjects receive effective supportive care). However, as shown with three-arm trial, it is incorrect to make the transitive inference that, when 70% of the subjects receive effective supportive care, the results for A and C would differ.

Baker and Kramer BMC Medical Research Methodology 2002 2:13   doi:10.1186/1471-2288-2-13
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