for opioid abuse and dependence criteria that included legal problems was suggested (Shand et al., 2011), although a well-fitting unidimensional model from these data with only half the parameters appeared more parsimonious (Hasin, 2011). These two studies offered important information on unidimensionality. However, neither study addressed craving, differential item functioning (also known as measurement invariance, i.e., whether the criteria function differently according to characteristics of respondents such as gender or age), or whether abuse criteria and craving added significant information to the existing dependence criteria, which have extensive reliability and validity evidence (Hasin et al., 2006a).
