The IRT analysis indicated that the thresholds for the 11 symptom criteria do not align with the DSM-IV conceptualization of AUD, a finding consistent with other FA (Harford and Muthén, 2001) and IRT analyses (Langenbucher et al., 2004; Martin et al., 2006; Saha et al., 2006). Dependence criteria for tolerance and time spent had low item thresholds and discrimination, whereas abuse criteria for legal problems and role obligation failure had higher thresholds and discrimination. Tolerance, time spent, and hazardous use (males only) had lower item thresholds (i.e., higher endorsement) and low item discrimination. They tapped lower levels of AUD severity in the IRCs and were well separated from the other symptoms, especially in the two younger age groups. As reported in the MIMIC analysis, these items also exhibited significant item bias among the younger age groups when compared with adults ages 26 and older.
