Concurrent Validity refers to the extent to which test scores correlate with scores on other relevant measures administered at the same time.
Concurrent Validity is the type of Validity demonstrated when scores obtained from a new measure are directly related to scores obtained from a more established measure of the same variable.
Other definition:
Concurrent validity refers to a form of criterion validity that correlates test scores with measures of job performance for employees currently working for an organization.
Other definition:
Concurrent validity refers to an assessment of whether a test is measuring what it claims to be measuring by correlating scores with some currently available relevant criterion (e.g., school performance).
Other /More definition:
Concurrent validity is the extent to which a test yields the same results as other measures of the same phenomenon