Research Glossary

Adverse Reaction

(Adverse Event.) An unwanted effect caused by a drug or treatment. The reaction may occur suddenly or develop over time. (Also called a "Side Effect.")

Appproved Drug

New substances must go through a process with the Food and Drug Administration (FDA) prior to receiving approval for marketing to the public. This process includes pre-clinical laboratory and animal studies, clinical trials for safety and efficacy, filing of a New Drug Application by the manufacturer of the drug, FDA review of the application, and FDA approval/rejection of application.


Term that refers to randomized trials where participants are not told which arm of the trial they are on. In clinical trials, participants are unaware whether they are in the experimental or the "control" arm of the study. The control group does not receive the treatment. (Also called "Masked.")

Clinical Trial

A research study formed to answer specific questions about new therapies or new ways of using known treatments. Clinical trials are used to determine whether new drugs or treatments are both safe and effective and are often conducted in four phases: Phase I tests a new drug or treatment in a small group; Phase II expands the study to a larger group of people; Phase III expands the study to an even larger group of people; and Phase IV takes place after the drug or treatment has been licensed and marketed.

Confidentiality Regarding Trial Participants

Although trial participants' consent to the use of their records for data verification purposes, research staff must maintain and protect the personal and medical information of the participants.

Control Group

In a clinical trial, one group of patients is given an experimental drug or treatment, while the control group is given either a standard treatment for the illness or a placebo (fake treatment or sugar pill). The control group is the standard by which experimental observations are evaluated.

Double-Blind Study

A clinical trial in which neither the participants nor the research staff knows which participants are receiving the experimental treatment and which are not.

Inclusion/Exclusion Criteria

Medical or social standards that determine whether a person may or may not be allowed to enter a clinical trial. Criteria may be based on factors as age, gender, the type and stage of a disease, previous treatment history, and other medical conditions. Inclusion/exclusion criteria are not used to reject people personally, but to identify appropriate participants and ensure their safety.

Informed Consent

Process of learning the key facts about a clinical trial before deciding whether or not to participate. Once an individual agrees to participate, informed consent is a continuing process or providing participants information throughout the study.

Institutional Review Board (IRB)

Every institution that conducts or supports research involving human participants must, by federal regulation, have an IRB that approves and reviews all research protocols. This is to protect the rights of all human participants. The IRB is a committee of physicians, statisticians, researchers, community advocates, and others that ensures that a clinical trial is ethical and that the rights of study participants are protected.

Investigational New Drug

A new medication, such as an antibiotic drug, or any type of biological drug that is used in a clinical investigation. These would also include any type of a biological product used in vitro for diagnostic purposes, such as the type of substances a person would ingest or have injected prior to having a radiologic exam.


An inactive pill, liquid, or powder that has no treatment value. This is sometimes referred to as a "sugar pill." In clinical trials, experimental treatments are often compared with placebos to see whether the treatment is effective. In some studies, the participants in the control group will receive a placebo instead of an active drug or treatment. However, in studies where participants are ill, researchers do not give a placebo if there is a known beneficial treatment available.

Placebo Controlled Study

A research study in which an inactive substance (the placebo) is given to one group of participants, while the drug being tested is given to another group. The results obtained in the two groups are then compared to see if the investigational treatment is more effective in treating the condition.

Standard Treatment

The treatment currently and commonly used by the medical community for the treatment of a specific condition or illness.

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