What does "discriminant validity" assess?

Discriminant validity assesses the uniqueness of a test by ensuring that it does not correlate with other constructs that it should theoretically be different from. This type of validity is crucial in confirming that a measure is capturing one specific construct without being unduly influenced by other similar constructs. For example, if a depression scale is being evaluated for discriminant validity, it should show low correlations with measures of unrelated constructs, such as physical health or intelligence. This supports the view that the test is measuring what it was intended to measure without being confounded by other variables.

The other options do not accurately capture the essence of discriminant validity. Assessing a test's accuracy in measuring a specific construct relates more to construct validity as a whole, rather than just discriminant validity. The correlation between two similar constructs reflects convergent validity, which examines whether measures that are theoretically related are indeed correlated. Overall reliability of a measurement tool deals with the consistency of the results over time or across items, which is a separate aspect of psychometric evaluation. Thus, the focus of discriminant validity is strictly on ensuring low correlation with distinct constructs.