Methods for detecting differential item functioning (DIF) and scale (or construct) equivalence typically are used in developing new measures, adapting existing measures, or validating test score inferences. DIF methods allow the judgment of whether items (and ultimately the test they constitute) function in the same manner for various groups of examinees, essentially flagging problematic items or tasks. In broad terms, this is a matter of measurement invariance; that is, does the test perform in the same manner for each group of examinees? You will be introduced to a variety of DIF methods, some developed by the presenter, for investigating item-level and scale-level (i.e., test-level) measurement invariance. The objective is to impart psychometric knowledge that will help enhance the fairness and equity of the inferences made from tests. Topics include: (a) What is measurement invariance, DIF, and scale-level invariance? (b) Construct versus item or scale equivalence (c) Description of DIF methods (d) Description of scale-level invariance, (e) Examples, and (f) Recommendations.