What does “validity” mean, when used to describe a test?
Test validity is the accuracy with which a test measures the trait it claims to measure. The test must first have adequate reliability, as described above. To be valid, content of the test questions should look right; a test claiming to measure arithmetic addition skills should consist of addition problems, not subtraction or division problems. A test of the personality trait of Extroversion should contain items about social interactions with people, not feelings of depression or anxiety. Another way to document validity is to see if scores on the test are concurrently related as expected to other information, such as scores on other tests that are trusted to measure the same thing and other information to which the trait is related. For example, verbal intelligence is known to be positively related to school grades; persons with higher intelligence tend to get higher grades. Therefore, any test of verbal intelligence should show such a positive relationship.
