对照的意义在于使处理因素和非处理因素的差异有一个科学对比。处理因素的效应大小，重要的不是其本身，而是通过对比所得出的结论才有意义。医学上有许多疾病是可以自愈的，至于能自行减轻和缓解的疾病则更为多见，所以设立对照组是必不可少的。对照的形式包括空白对照、实验 The significance of the control is that there is a scientific comparison of the difference between the treatment and the non-treatment. The size of the effect of the treatment factors, the important thing is not itself, but through the comparison of the conclusions made sense. Many diseases in medicine are self-healing, but diseases that can relieve and relieve themselves are even more common, so setting up a control group is indispensable. Controlled forms include blank controls, experiments