Randomization in Clinical Trials

In some phase 2 and all phase 3 clinical trials, patients are assigned to groups that receive different treatments. The process of assigning patients to these groups by chance is called randomization. Learn how researchers randomly assign clinical trial participants to different treatment groups in order to prevent bias in the results.
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Randomization in Clinical Trials. Certain cancer treatment trials test whether a new treatment works better or worse than the usual treatment. If you join such a trial, a computer may be used to randomly assign you to either the usual treatment group or the new treatment group. This is called randomization. While at first it may seem unfair that you can’t choose which treatment you’ll receive, there is an important reason why. Randomization helps ensure that the trial’s results will be trustworthy. That’s because randomization helps prevent false results due to bias. Bias occurs when a trial’s results are affected by factors not related to the treatment being tested. For example, without realizing it, a doctor might assign healthier patients to the new treatment group and sicker patients to the usual treatment group. This could make the new treatment seem more effective or safer than it really is. When you join a clinical trial, you can trust that the doctors and nurses will take great care of you no matter which group you’re assigned to. Randomization helps researchers make real progress against cancer. And so do you. Thank you for your participation. For more information, go to www.cancer.gov/clinicaltrials