Randomization is used in all phase III and some phase II trials. These trials are called randomized clinical trials. A clinical trial consists of at least two groups depending upon the study protocol. A study protocol is a plan that describes the schedule of tests, procedures, medications and dosages, and the length of the study.
One group of patients will receive the experimental drug or treatment, this is the investigational group. One group of patients will receive either the standard of care or a placebo which has no therapeutic value, this is the control group.
Placebos are almost never used in cancer treatment trials.
Comparing these groups to each other often clearly shows which treatment is more effective or has fewer side effects. If you are thinking about joining a randomized clinical trial, you need to understand that there is an equal chance you will be assigned to either group. Neither you nor your doctor chooses which group you will be in.
If you participate in such a randomized clinical trial, you will be assigned by chance to either an investigational group or a control group. Your assignment will be determined at random and no one will know which group you are in.
Regardless of which group they are in, all patients receive the same level of medical attention and care. In most clinical trials, the health of the participants is monitored both during and after the study period. Clinical trials are highly controlled and regulated by the government.