What is the definition of Discriminant Validity?

Discriminant validity is a critical concept in psychological testing and measurement that refers to the extent to which a test or measurement does not correlate with other measures that it should theoretically be unrelated to. This form of validity ensures that the instrument is indeed measuring the intended construct and not capturing aspects of other constructs.

The correct choice relates to the idea that a measurement shouldn't assess constructs it is not intended to measure. Essentially, high discriminant validity indicates that a particular measure does not show a significant correlation with other measures that are conceptually distinct, thus affirming that it possesses the specificity needed for accurate measurement.

The other options either address concepts related to different aspects of validity or measurement. For example, measuring the same construct simultaneously pertains to convergent validity, which deals with how closely related different measures of the same construct are. A strong negative relationship refers to the type of correlation, while correlation with relevant standards relates to criterion-related validity, focusing on how well one measure predicts an outcome based on another relevant measure. These distinctions highlight the specific focus of discriminant validity on ensuring that a measurement is distinct from unrelated constructs.