Glossary
A practical glossary of common clinical research terms used in listings, screening, and consent documents.
Last updated: February 27, 2026
Core terminology
Simplified definitions for practical understanding. Terms may vary by protocol and context.
Adverse Event (AE)
An unwanted medical event that occurs during a study. An AE may or may not be caused by the study intervention.
Blinding / Masking
A study design method where participants and/or staff do not know which group a participant is assigned to, to reduce bias.
Completion Bonus
Additional compensation provided for completing a defined set of study activities, such as all required visits.
Consent (Informed Consent)
A process and document describing procedures, risks, potential benefits, alternatives, and participant rights.
Eligibility (Inclusion/Exclusion Criteria)
Rules that determine who can and cannot participate, often based on age, medical history, medications, and labs.
Endpoint / Outcome
A measurement used to determine whether the intervention or observation produced an effect.
Institutional Review Board (IRB)
An ethics committee that reviews studies to help protect participants and ensure appropriate safeguards.
Interventional Study
A study where participants receive a study intervention and outcomes are measured.
Observational Study
A study that observes outcomes without assigning an intervention; may include surveys, monitoring, or records review.
Placebo
An inactive comparison used in some trials to assess the effect of the study intervention.
Protocol
The written study plan that defines procedures, schedule, eligibility, and outcomes.
Randomization
Assignment of participants to study groups by chance rather than choice, often to reduce bias.
Reimbursement
Repayment for costs related to participation that may be separate from compensation.
Screening Visit
An initial visit where consent is reviewed and assessments are performed to determine eligibility.
Serious Adverse Event (SAE)
A more severe adverse event, often defined by outcomes such as hospitalization; definitions are protocol-based.
Study Coordinator
A staff member who manages participant scheduling, communication, and protocol procedures at the site.
Visit Window
A time range during which a visit or task must occur to remain protocol-compliant.
Note: Ask the site to define terms in writing for the specific protocol you are considering.