Thu. Feb 25th, 2021

the concept of validity is one which is basic to the consideration of quality of a test instrument. Along with those of reliability, adequate applicability (see for coverage, and instance Oller, 1979, Valette, 1977, the concept of validity determines whether or not we are being fair to the testees. Specifically, the concept of validity touches on the degree to which the test instrument measures what it is designed to measure and not something else.