Double-Blind, Placebo-Controlled Clinical Trial

Updated November 06, 2016

Definition:

To fully understand this term, we need to break it down into its components:

A clinical trial is one that involves human participants and seeks to answer specific questions about a type of medical intervention. This can be a drug or other type of treatment, such as nutritional changes or massage.

Because patients don't know what they're getting, their belief about what will happen doesn't taint the results. Because the researchers don't know either, they can't hint to patients about what they're getting, and they also won't taint results through their own biased expectations about what the results will be.

If researchers do know who's getting the treatment but the participants do not, it's called a single-blind trial.

A placebo is an inactive substance (often a sugar pill) given to a patient in place of medication.

In drug trials, a control group is given a placebo while another group is given the drug (or other treatment) being studied. That way, researchers can compare the drug's effectiveness against the placebo's effectiveness.

Placebo-controlled refers to a control group receiving a placebo. This sets it apart from studies that simply give participants a treatment and record the results.

Thus, a double-blind, placebo-controlled clinical trial is a medical study involving human participants in which neither side knows who's getting what treatment and a placebo is given to a control group.

Before getting to this stage, researchers often perform animal studies, clinical trials not involving a control group, and single-blind studies.