At this point in time, the most widely used instrument is the MacCAT-T (Grisso, Appelbaum, & Hill-Fotouhi 1997). It reflects the most widely influential theory of competence to date, that of Grisso and Appelbaum (1998). At the core of this theory are the same four abilities mentioned in §4 of this entry: the ability to communicate a choice, the ability to understand, the ability to appreciate, and the ability to reason. However, Grisso and Appelbaum (1998) develop detailed specifications f