What is a Randomized Clinical Trial?

Randomized Clinical Trials – Overview

New medications and therapeutic agents are approved for use by the Food and Drug Administration or FDA. FDA approval is based on the results of the clinical trials and studies that have been performed to test the safety profiles and efficacy of the target drug.

One of the most well-founded methods for testing the efficacy of new treatment modalities and options is a randomized clinical trial (RCT).

What is a Randomized Clinical Trial?

An RCT is an interventional study that is performed on two distinct groups of study participants to test the effectiveness of a specific medical treatment.

This study type was formed in the 1930s by researchers in an attempt to reduce bias often seen, in the past, with clinical studies.

For a TCY, participants in the study are divided into two groups; the interventional group and the control group.

As the name describes, the interventional group receives the drug or therapy that is being studied and the control group receives either a placebo drug, fake treatment, or no treatment at all.

The presence of a control group allows researchers and pharmaceutical companies to assess the overall benefits of the drug and see if the treatment is equally effective in all patients.

Moreover, if a control group that hasn’t been given any treatment, when compared to an interventional group taking the experimental drug, has the same disease progression or regression, then it can be easily understood that the drug is not beneficial and the change in health may be the result of other factors.

It is important to note that an RCT can have more than one control group and more than one treatment can be assessed at a time. An RCT can also be performed for different reasons such as to test the effectiveness, inefficacy, and neutrality of treatment.

How is a Randomized Clinical Trial Performed?

An RCT is the gold standard of all clinical trials and is the preferred method of experimental study by the FDA. For an RCT to be performed, three important factors need to be present:

  • Two groups of study participants need to be selected, both of which must have the same illnesses.
  • The study participants are randomly assigned to either the control group or the interventional group.
  • There must be blinding as in neither the doctor nor the patient is aware of the grouping. This is to reduce biased results as doctors or patients may have personal factors resulting in skewing of data. However, RCTs can be unblinded or open in cases where blinding is not possible. For example, if the treatment is a form of physical therapy that requires patients to be aware of their therapy.

The results of the study are analyzed such that the statistical results of the RCT are interpreted to check the probability of false positive and false negative results is determined. After that, the results are subjected to peer review and eventually, review by the journal before they can be published.

Why Randomized?

The main reason behind randomization is so to prevent selection bias in the study. The presence of selection bias is grounds for disqualification of the clinical trial and should be avoided at all costs.

If randomization is not performed, there is a possibility that doctors or patients may report biased results.

For example, in a study to determine the inefficacy of a drug, a doctor or researcher may assign a patient with low chances of recovery to the interventional group.

This would prove the study’s hypothesis but the results would be completely skewed and biased. To prevent this from happening, RCTs are preferred.

Advantages of Randomized Clinical Trials

RCTs are the backbone of scientific studies and the main advantage of these, apart from those mentioned above, is that they conduct thorough research and can change clinical practices for the better.

Many RCTs have scientifically proven and concluded that certain clinical practices were wrong and that changing them would be more beneficial for the patients.

Disadvantages of Randomized Clinical Trials

RCTs are the gold standard of scientific studies however, certain disadvantages explain why they are not performed and completed more frequently:

  • RCTs are extremely costly and time-consuming. On average, RCTs cost approximately 12 million dollars, and although the results produce more than the spending cost, it often takes up to 10-12 years. This means that the financial reimbursement is delayed and finding funding for that long may be difficult.
  • A larger sample size is required. This is because RCTs are performed for long periods and have a high risk of participants either dropping out or losing contact.
  • Possible conflict of interest. Depending on the funding for the study, there has been a significant link between pharmaceutical companies funding an RCT and positive results being reported. This is a conflict of interest and there are now rules preventing doctors from taking funding from the company that manufactures the drug they are studying.


    • Chalmers TC, Smith H Jr, Blackburn B, Silverman B, Schroeder B, Reitman D, Ambroz A (1981). “A method for assessing the quality of a randomized control trial”. Controlled Clinical Trials. 2 (1): 31–49.
    • Bhandari M, Busse JW, Jackowski D, Montori VM, Schünemann H, Sprague S, Mears D, Schemitsch EH, Heels-Ansdell D, Devereaux PJ (2004). “Association between industry funding and statistically significant pro-industry findings in medical and surgical randomized trials”. Can Med Assoc J. 170 (4): 477–80.
  • Johnston SC, Rootenberg JD, Katrak S, Smith WS, Elkins JS (2006). (PDF). Lancet. 367 (9519): 1319–27.

See Also

Medical Innovation Grant Opportunities

Most Recent Weight Loss Clinical Trials

Follow us