Clinical Trial Terminology

Protocol: A document that outlines the set of rules and directions for conducting a clinical trial.

Masked/Double-Masked: Some studies have different treatment regimens within them, and patients are assigned to one regimen. In order to eliminate bias, some study staff and the patient may not know the treatment regimen to which they are assigned; they are said to be “masked” to the treatment assignment. When both the doctor and patient do not know which treatment regiment the patient is receiving, the study is said to be “double-masked.”

Sponsor: The institution providing funding for a trial; most trials are sponsored by pharmaceutical companies.

Principal Investigator: The lead physician on a trial; this person is ultimately responsible for the conduct of the trial at their site.

Randomization: The process by which a patient is assigned to a study treatment; this process is random, like flipping a coin.