Validity

Validity is how much accuracy, utility, and meaningfulness the interpretation of a measure's scores have for a particular purpose. There are multiple aspects of validity. Validity is not a characteristic that resides in a test. The validity of a measure's scores reflects an interaction of the properties of the test with the population for whom it is designed and the sample and context in which it is administered. Thus, when reporting validity in papers, it is important to adequately describe the aspects of validity that have been considered and the population, sample, and context in which the measure is assessed.

There are many types of measurement validity, but the central psychometric aspect of measurement validity is construct validity. That is, whether the measure accurately assesses the target construct is the most important consideration of measurement validity. Construct validity includes the nomological network of the construct and subsumes other key types of measurement validity, including convergent, discriminant (divergent), criterion-related, concurrent, predictive, and content validity.

A measure can be no more valid than it is reliable.