Randomized clinical trial

Randomized clinical trial (RCT) is a type of scientific experiment or observational study in medicine that aims to reduce bias when testing a new treatment. The people participating in the trial are randomly allocated to either the group receiving the treatment under investigation or to a group receiving standard treatment (or placebo treatment) as the control.

Overview

RCTs are considered the gold standard in a clinical trial. They are often used to test the efficacy or effectiveness of various types of medical intervention and may provide information about adverse effects, such as drug reactions. Random assignment of intervention is done after subjects have been assessed for eligibility and recruited, but before the intervention to be studied begins.

Methodology

In a randomized clinical trial, the method of selection is the key factor, not the randomness per se. The random assignment in real-world practice can be complex; for instance, it can involve stratified randomization, for several reasons including (1) to ensure balanced groups in small trials (2) to incorporate prognostic factors and (3) to reduce bias and increase the precision of the estimate of the treatment effect.

Types of RCTs

There are several types of RCTs, including:

• Parallel-group trial: This is the simplest kind of RCT. Participants are randomly assigned to a treatment group and the outcomes are compared with those of a control group.
• Crossover trial: Participants receive one treatment, and then switch to another. This type of trial is often used when the treatments are not expected to have lasting effects.
• Factorial trial: Participants are randomly assigned to a combination of treatments. This type of trial can test the effect of more than one intervention.

Limitations

While RCTs are considered the gold standard in clinical trials, they do have limitations. These include the potential for lack of applicability to general practice, ethical concerns, and the fact that they can be expensive and time-consuming to conduct.

See also

• Clinical study design
• Evidence-based medicine
• Medical research

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