In a letter published last month in The Lancet,&nbsp;doctors, scientists, and bioethicists from a wide range of countries – including Guinea, Ghana, Nigeria, and Senegal, as well as Britain, France, Hong Kong, and the United States – argued that a randomized trial is justified only when there is “equipoise,” or balance, between the two options offered. This can happen when doctors do not know whether a proposed treatment will do more harm than good, or when they are in doubt about which of two treatments is more likely to cure the patient.
在治疗问题上，情况有所不同。在《柳叶刀》（The Lancet）上个月刊登的一封信中，来自多个国家和地区的医生、科学家和生物伦理学家&mdash;&mdash;包括圭亚那、加纳、尼日利亚、塞内加尔以及英国、法国、中国香港和美国&mdash;&mdash;指出随机试验只有在两组对象之间存在“均势”（平衡）的情况下才有效。医生不知道备选治疗是否弊大于弊时，或他们不清楚两种治疗哪种更有可能治愈患者时属于这种情况。