Validity
Lead Author(s): Jeff Martin, MD
Types of Validity
There are two types of validity:
- External : Inference from the study sample to other external populations.
Measures of Validity
Validity is measured in terms of sensitivity (ability to measure who HAS the characteristic: disease or exposure) and specificity (ability to measure who DOES NOT HAVE the characteristic: disease or exposure).
Importance of Validity
In terms of study validity, though, the key question is not when is the study being carried out, but:
- when were the measurements made and