Clinical Trial Terminology
Reviewed by: HU Medical Review Board | Last Reviewed: January 2016. | Last updated: January 2022
There are several terms that are commonly used when discussing clinical trials. Here are some that come up often:1,2
Adverse event: an undesirable experience associated with the use of a medical product in a participant.
Arm: a grouping of study participants who receive a specific intervention, or no intervention, according to the study protocol.
Baseline characteristics: data collected at the beginning of the study for each participant, including demographics like age, gender, and race. Data for study-specific characteristics like prior treatment, weight, etc., will also be collected.
ClinicalTrials.gov identifier (NCT number): the unique identification code assigned to each clinical trial that is registered on ClinicalTrials.gov.
Controlled Trial: A type of clinical trial that examines an intervention compared with a standard (called the control).
Double Blind Trial: A clinical trial where at least 2 parties involved, usually the patient and the investigator, do not know what intervention the patient is receiving. This is to avoid potential bias.
Exclusion Criteria: Factors that would prevent a person from participating in a study.
FDA: Food and Drug Administration.
Inclusion Criteria: Factors that allow a person to participate in a study.
Intervention: The focus of the clinical study. This could be a drug, a medical device, a medical procedure, other investigational products, as well as surveys, education, or interviews.
Investigator: A person who is conducting research of a clinical study.
Open Label: A term describing a clinical trial where blinding is not used. All parties involved know which study participants have been assigned to which interventions.
Outcome Measure: A measurement that is outlined in the study protocol that is used to determine the effect of the intervention.
Placebo: A substance that does not contain active ingredients and is designed to appear the same as the intervention being examined.
Primary Outcome Measure: The main outcome measure that is evaluating the effect of the study intervention.