在上一讲中,已谈到临床试验必须有对照组,而且这个对照组应该和试验组同时观察。但仅仅如此,仍然不够,这里还有一个怎样分组的问题。也就是说如何决定谁应被分入试验组,谁应被分入对照组。由研究者来决定也许是最省事的办法,可是由于人们的主观决定经常受许多社会、心理因素影响,自觉或不自觉地会产生偏向,使对照组与试验组之间产生不均衡,失去可比性。一个极典型的例子是1930年英国曾进行过一次关于给小学生补一餐牛奶对生长发育影 In the last lecture, it has been mentioned that clinical trials must have a control group, and this control group should be observed simultaneously with the experimental group. But that’s not enough, and there’s a question of how to group it. That is to say, how to decide who should be assigned to the test group, who should be assigned to the control group. It may be the most easy way for the researchers to decide. However, because people’s subjective decisions are often influenced by many social and psychological factors, they are consciously or unconsciously biased, resulting in an imbalance between the control group and the experimental group. Sex. A very typical example is the United Kingdom in 1930 once conducted a study on primary school students to fill a meal of milk on the growth and development