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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.

 

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

Internal Validity

Definition: The extent to which the results of a clinical research study are not biased. Several characteristics of a study affect its internal validity. Are the two groups of people being compared similar in all the important characteristics that may affect the measurements of data? Are the data collected being measured using accurate methods?

Example: For example, a study was performed comparing people receiving a new type of surgical treatment to people who had received a different treatment in an earlier year. The researchers concluded that the people who received the new treatment had less pain. However, the method used to measure how much pain they had was different for the earlier year than for the new treatment. This study was felt to have poor internal validity because of the difference in the method of measuring pain.

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