The outcome of randomized controlled trials can vary depending on the eligibility criteria Coaster Set of the patients entering into the trial, as well as the heterogeneity of the eligible population and/or the interventions.If the subject population and/or interventions are heterogeneous, the final outcome of the trial depends on the degree of concordance of effects of the subgroups Crop Tee of interventions on the subgroups of the subject population.The considerations that go into the calculation of sample size and determination of the study stopping rules also would affect the nature of the outcome of the study.
In this paper we try to examine these phenomena with respect to the recent trials on endovascular therapy in acute ischemic stroke.