Adverse event: any unexpected change in health or any side effect that occurs in a person while they are still under the effect of a treatment in a clinical trial.  All adverse events must be reported to an institutional review board, whether they are serious or minor.

Assent: a child’s consent to participate in a clinical trial.

Blinded study: a study done in such a way that the study participants do not know whether they are getting a placebo (an inactive substance) or a drug, but the study team does know.  If the study is comparing two different doses or two different medications, then the human participants do not know which they are getting.  In a “double-blinded study”, neither the study participant nor the investigator know which treatment any one study participant is getting. That information is revealed only once the treatment is over.

Clinical investigation or ‘clinical research’ or ‘clinical study’ or ‘clinical trial’: research that either directly involves human participants or uses materials of human origin (for example, blood) to test the safety and/or effectiveness of drugs, medical devices, procedures, or preventions.

Confidentiality: the assurance that a participant’s information will be kept secret and that access to that information is limited to authorized persons.

Control group: the group of participants who resemble the experimental group, (for example, they are in the same age range) but who do not receive the experimental treatment.  Changes are measured in both the treatment group and this group, to compare the effect of the new drug, medical device, procedure, or prevention.

Data: series of recorded observations, measurements, or facts (about the participant).

Effectiveness/efficacy: whether a new drug or treatment works. An effective drug or prevention will improve health or successfully prevent a disease.

Experimental drug or device:  see Investigational drug or device.

Experimental group: the group of subjects exposed to the new, researched treatment.  This group is often compared to a ‘control group’, the subjects who are are not exposed to that treatment.

FDA (Food and Drug Administration): an agency of the United States federal government that approves or disapproves new drugs and devices.

Human subject: a participant who volunteers to be in a clinical study.

Informed consent: a patient’s written consent to participate in a clinical study after fully discussing with the researchers all the relevant health-related facts and the risks involved.

Institutional Review Board, “IRB”: a committee that has been formally designated to protect the people involved in research.  This board must review and approve each clinical study that involves humans subjects, with the aim to protect each person’s safety, rights, privacy and welfare.

Investigation: see Clinical investigation

Investigational drug/device: a new medical drug and/or device that has been tested in a laboratory but has not yet been approved by the Food and Drug Administration (FDA) to be legally sold and used by health care providers and/or patients.

Investigators: These are researchers.  They are scientists who manage clinical studies. The lead investigator of a study is also called the “Principal Investigator.”

Participant: also known as a "human subject", a person who volunteers to be in a research experiment.

Placebo: a substance that has no therapeutic effect but is given merely to satisfy a patient who supposes it could be a medicine. Other names for placebos include ‘dummy pill’ or ‘sugar pill’.

Procedure:  In health care, this can be a test (such as taking blood to measure cholesterol) or a treatment (like surgery or an injection of a drug). In research, a trial's protocol describes the procedures (tests and/or treatments) carried out on or by the participants and/or investigators.

Protected health information (PHI): any information about a participant’s health history or status. By law, this is required to be kept confidential.

Protocol: a written plan for carrying out a clinical study. A protocol includes what will be done, when, and how.

Randomization: Mixing up the types of participants in enrolled into an experimental group or a control group, so that it will be fair to compare the two groups. For example, if the experimental group had a lot more elderly people than the control group, and the test drug didn't work in the experimental group, it wouldn't be fair to conclude that the drug didn't work, because there might be something in elderly people's metabolism to prevent the drug from working well. So a mix of people should go into the group that gets the drug, and a mix of people should go into the control group.

Randomized controlled trial (RCT):  a scientific experiment that tests a new treatment or device by randomly dividing participants to receive either the treatment under investigation, or a control condition that does not receive the investigated treatment.

Research: gathering of information to help increase our knowledge. Clinical research involves human volunteers. Sometimes clinical research tests drugs or devices or procedures in human participants; but research always involves measuring something--for example, whether blood pressure went down in participants receiving a new drug, and whether it stayed the same in the participants (controls) who didn't receive the drug.

Researcher: a person who carries out an investigation (another word that can be used for “investigator”).

Sponsor: a person, organization, company, institution, or government agency that provides funds (money) or other resources for a clinical study.

Study: see Clinical investigation

Study Coordinator: a key member of the research team who works for the principal investigator, or lead researcher. He/she is the person who is usually responsible for the daily activities of the clinical study.

Subject:  subject or ‘human subject’ is a term describing the person who volunteers to be in a research experiment.  Also called a research participant.

Trial: see ‘clinical investigation’

Volunteer: a person who willingly participates in a clinical study.