Arm

One of the groups in a study, each receiving something different.

Learning 

What it means

An arm is a group of participants who all receive the same thing. A two-arm study might have one arm receiving the new treatment and another receiving a placebo.

Why it matters if you take part

The number of arms tells you how many different things are being compared, and how many possible groups you could be assigned to.

Related terms

This explains how clinical research works. It is not medical advice and does not describe any specific condition or treatment. Only a trial site can determine whether someone can take part in a study.