Convergent validity
Convergent validity, is the degree to which an operation is similar to (converges on) other operations that it theoretically should also be similar to. For instance, to show the convergent validity of a test of mathematics skills, the scores on the test can be correlated with scores on other tests that are also designed to measure basic mathematics ability. High correlations between the test scores would be evidence of a convergent validity.

Convergent validity shows that the assessment is related to what it should theoretically be related to.

It is ideal that scales rate high in discriminant validity as well, which unlike convergent validity is designed to measure the extent to which a given scale differs from other scales designed to measure a different conceptual variable. Discriminant validity and convergent validity are the two good ways to measure construct validity.

The validity of a measure ought to be gauged by comparing it to measures of the same concept developed through other methods.
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