The Fronell-Larcker criterion is one of the most popular techniques used to check the discriminant validity of measurements models.
Your main reason for conducting discriminant validity for your study will be to show how distinct an item or set of items is from others.
According to Gefen and Straub (2005), “discriminant validity is shown when each measurement item correlates weakly with another construct excepts for the ones to which it is theoretically associated”.