true negative rate
The specificity of a test is its ability to identify correctly people without the target condition. A test with high specificity will be negative for most of the people who do not have the condition, and have few false positive results.
For example, if 90 out of 100 patients in a study do not have cancer (based on the reference standard test), the specificity of that test for ruling out cancer is 90/100 or 90%.
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