Trial glossary
Research terms in plain language
Quick definitions for words you will see in study listings and consent documents.
- Arm
- A group within a study that follows a specific plan, such as receiving a study product or a comparison.
- Blinding
- When volunteers, researchers, or both do not know which group a person is in, to reduce bias.
- Control group
- The group that receives a standard option or placebo so results can be compared.
- Eligibility criteria
- The rules a study team uses to decide who can join. Each independent study sets its own.
- Endpoint
- The result a study measures to answer its main question.
- Informed consent
- The process where the study team explains a study and a volunteer agrees to join, with the right to leave anytime.
- Institutional Review Board (IRB)
- An independent committee that reviews research plans to protect volunteers.
- Observational study
- Research that records information without assigning a study product.
- Placebo
- An inactive substance that looks like the study product, used for comparison.
- Protocol
- The detailed written plan that describes how a study will be run.
- Randomization
- Assigning volunteers to groups by chance so groups are comparable.
- Sponsor
- The organization that funds or oversees a study.
- Study visit
- A scheduled appointment with the study team, in person or remote.