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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.

 

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Masking

Definition: A way of making sure that the people involved in a research study — participants, clinicians, or researchers — do not know which participants are assigned to each study group. Masking usually is used in research studies that compare two or more types of treatment for an illness. Masking is used to make sure that knowing the type of treatment does not affect a participant's response to the treatment, a health care provider's behavior, or assessment of the treatment effects.

Example: For example, masking is usually done in a type of study known as a randomized controlled trial. The participants are considered "blinded" if they do not know whether they are taking the drug being researched or a placebo. When neither the participants nor the researchers know who is taking the drug, the study is called "double-blinded."

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