Concurrent Validity:
The concurrent validity of survey instruments, like the tests used in psychometrics , is a measure of agreement between the results obtained by the given survey instrument and the results obtained for the same population by another instrument acknowledged as the "gold standard".
The concurrent validity is often quantified by the correlation coefficient between the two sets of measurements obtained for the same target population - the measurements performed by the evaluating instrument and by the standard instrument.
For example, a researcher has developed a new fast IQ-test that requires only 5 minutes per subject, as compared to 90 min for the test acknowledged as the gold standard. The researcher administers both tests for each person in a group of, say, 50. The outcome is 50 pairs of IQ-scores - one pair for each person: the score obtained by the new test and the score obtained by the gold standard test. The value of the correlation between the two sets of scores is a quantitative measure of the concurrent validity of the new IQ-test.
The concurrent validity is a form of the criterion validity .