Glossary of Terms

We know that many of the concepts used on this site can be difficult to understand. For that reason, we have provided you with a glossary to help you make sense of the terms used in Comparative Effectiveness Research. Every word that is defined in this glossary should appear highlighted throughout the Web site. When you come upon a highlighted term and would like to read the full definition, you can either click on the word to visit the glossary or roll your mouse over the word for a pop-up definition.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Absolute Risk

The probability or chance that a person will have a medical event. Absolute risk is expressed as a percentage. It is the ratio of the number of people who have a medical event divided by all of the people who could have the event because of their medical condition. detail

Adverse Drug Reaction

A bad or harmful reaction to a drug that is used to treat or prevent a disease. detail

Adverse Effect

Anything that a person might feel is a negative or harmful result of a treatment or test. detail

Adverse Event

Any negative or unwanted effect from any drug, device, or medical test. detail

Adverse Reaction

Any negative or unwanted effect from a drug, device, or medical test. detail

Analysis

The process of preparing the results or conclusions of a study. An analysis usually is performed by doing mathematical calculations known as statistics. detail

Association

A relationship. In research studies, association means that two characteristics (sometimes also called variables or factors) are related so that if one changes, the other changes in a predictable way. An association does not necessarily mean that one variable causes the other. detail