Causal estimates for external controls. How reasonable are the assumptions?
本文评估了在随机临床试验中使用外部对照的因果模型所依赖的五个关键假设，并以脊髓性肌萎缩症试验为例指出其中四个假设明显不成立，提醒试验者谨慎应用该方法。
Abstract A causal model has been proposed for including external controls in randomized clinical trials that is based on five critical assumptions and has been illustrated using the example of two trials in spinal muscular atrophy. It is argued that four of these assumptions are obviously false in the example used and that this would be a problem for many cases where one sought to use the approach. The claimed superiority to Bayesian methods is debatable, since trial effects have not been allowed for. It is concluded that trialists should be cautious in applying such an approach to using external controls.