A clinical study involves research using human volunteers (also called participants) that is intended to add to medical knowledge. There are two main types of clinical studies: clinical trials (also called interventional studies) and observational studies.

The process of enrolling in clinical trials is carefully regulated in order to protect the participants and maintain the clinical trial’s internal validity.

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People volunteer for clinical studies for many reasons. They may have a:

• Desire to improve medical care for future generations

• Connection to a certain disease or illness, whether through personal experience or through friends or family

• Personal interest in science