Commonly Used Terms - Definitions
A blinded study is one in which the subject and/or investigator
are unaware of what trial product a subject is receiving. In
a "single-blinded" study, the participants do not know whether
they are in an experimental group or a control group. In a "double-blinded" study,
neither the participants nor the researchers know which participants
are in which group.
A clinical trial refers to a carefully designed and controlled research study
in which one or more human subjects receive a drug or device for the purpose
of determining/testing the safety and/or effectiveness of drugs, devices,
treatments, or preventive measures in humans. Clinical trials can usually
be divided into four categories or "phases".
The terms "clinical trial" and "clinical study" are synonymous.
Participants in a control group are used as a standard for
comparison. For example, a particular study may divide participants
into two groups - an "experimental group" and a "control group." The
experimental group is given the experimental treatment under
study, while the control group may be given either the standard
treatment for the illness, a placebo, or no treatment. At the
end of the study, the results of the two groups are compared.
A product's ability to produce beneficial effects on the
course or duration of a disease.
Study participants in the experimental group receive the
drug, device, treatment, or intervention under study. In some
studies, all participants are in the experimental group. In "controlled
studies," participants will be assigned either to an experimental
group or to a control group.
FDA (Food and Drug Administration)
The FDA is the U.S. government agency that enforces laws
on the manufacturing, testing, and use of drugs and medical devices.
The FDA must approve a drug for marketing before it is made commercially
available to the public.
A human subject is a volunteer participant in a research
study, either as a recipient of the test article or as a control.
Informed consent is the participant's written agreement to
be in a study after being fully informed about what participation
will involve. Informed consent begins with a discussion between
the researchers and the prospective participants. The discussion
includes important information about the research study such
- What is the purpose of the study?
- What is involved? What types of procedures will
- What are the risks of participation?
- What are the benefits of participation?
- How long will the study take?
- Will my confidentiality be maintained? How?
- What happens if I get sick or hurt during the
- Why do I have to participate in the study? Is
- Can I quit at any time?
- Do I have to ask all of my questions at one
Institutional Review Board (IRB)
An IRB is a committee, comprised of medical, scientific and
non-scientific members, whose responsibility it is to review
all research projects involving human subjects being considered
by an institution. The primary purpose of the IRB review is to
assure the protection of the safety, rights and welfare of the
human subjects. At the University of Pennsylvania, the IRB is
called the "Committee on Studies Involving Human Beings."
Investigational or experimental device
An investigational or experimental device is a medical device
(such as an artificial heart valve or a screw used to hold bones
together) that has not yet received approval from the U.S. Food
and Drug Administration (FDA) for marketing.
Investigational or experimental drug/device
A drug or device being tested or used in a clinical trial,
including a product being used in a way different from its approved
form, for an unapproved indication/use, or to gain further information
about an approved use.
A placebo is an inactive substance. In blinded studies it
is usually made to look like the active product. It may be considered
a "sugar pill".
The principal investigator is the individual responsible
for the conduct of a clinical trial at a trial site.
The protocol is the formal design or action plan of a research
study that describes what will be done, when, how, and why.
Random allocation is assignment by chance to determine who
is in the experimental group and who is in the control group.
The sponsor is the company, research institution, group,
foundation, or government agency that takes responsibility for
the initiation, management and/or financing of a clinical trial