The process of assigning trial subjects to treatment or control groups is not done by the investigator or the patient. Each participant is randomly assigned to a treatment group. For example, a new investigational medicinal product is compared with a drug already approved on the market, the subjects are assigned randomly to one of two groups of studies that are as identical as possible. While one group receives the already approved drug, the other group receives the investigational product. Randomization should ensure the most equal distribution of participants with particular characteristics and possible influencing factors, thereby avoiding the influence of the deliberate allocation by the investigator.