Clinical Trial Randomization & Clinical Trial Statistics

This article explains clinical trial randomization and clinical trial statistics. It answers the question: What is randomization in clinical trials?
Back January 26, 2023

There are many statistical factors involved in any new treatment or drug in clinical trial research. Therefore, a certain practice called randomization is typically factored into clinical trial studies at a certain point. Randomization, according to the National Institutes of Health, U.S. Department of Health, is “the process by which treatments are assigned to participants by chance rather than by choice.” This is done to avoid bias when assigning volunteers to receive one treatment over another. This article will explain clinical trial randomization and some details of clinical trial statistics.

Many of these statistical factors also involve having a wide range of diversity in the study subjects for clinical trials. According to the National Institute on Aging (NIA), it is: “…important for clinical trials to have participants of different ages, sexes, races, and ethnicities. When research involves a group of people who are similar, the findings may not apply to or benefit anyone.” Therefore, many trials require a wide range of participants from different backgrounds, especially in the later phases. Diverse ages can affect the outcome of a study when it comes to developing a new medicine, because when the body ages, it reacts to medicines differently. Thus, age must be accounted for and is a key factor in clinical trial studies.

Researchers also want to observe if a new product, drug or therapy is actually better than an existing one in practice. These trials that are comparing one vs. another will involve a group of participants that will be assigned a placebo rather than the new experimental treatment. A placebo is an inactive product that resembles the one that has been developed and is now being tested; however, it does not have treatment value like the actual drug. Making the comparison of the new product tests to the placebo trials is one of the fastest and most reliable ways to determine the new product’s effectiveness. Placebo trials are not for everyone, as they are not an effective therapy. People needing real treatment may not get the one they need in placebo studies and should consult their doctor before joining.

In addition to randomization and placebo trials, there are also studies that are referred to as “blind” or “masked” studies. There are two types of blind studies:

  • Single-blinded: This type of study does not inform the participant what they are being given, but the research team is informed.
  • Double-blinded: Neither the participant nor research team is informed on what the participant is being given; only the pharmacist is aware.

The reason that double-blinded studies are conducted is so that research teams and the study applicants are prevented from manipulating any of the results. A double-blinded study eliminates any kind of bias from the research team; this allows for a more accurate collection of the scientific data. Unless medically necessary, the study participant remains unaware of what they are being administered in both types of these studies.

It is crucial to note that just because one is participating in a clinical trial, that does not always guarantee that the drug or treatment that is being tested in the trial will be given to the participant.

Works Cited

“Deciding to Take Part in Cancer Clinical Trials.”, US National Cancer Institute, 12 Feb. 2020,
Office of the Commissioner. “Informed Consent for Clinical Trials.” U.S. Food and Drug Administration, FDA, 4 Jan. 2018,
Office of the Commissioner. “What Are the Different Types of Clinical Research?” U.S. Food and Drug Administration, FDA, 4 Jan. 2018,
The American Cancer Society medical and editorial content team. “Types and Phases of Clinical Trials: What Are Clinical Trial Phases?”, American Cancer Society, Inc., 18 Aug. 2020,
“The Basics.” National Institutes of Health, U.S. Department of Health and Human Services, 20 Oct. 2017,

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