Standardized factor loadings for all dependence criteria (0.80–0.92) and for craving (0.89) were high in the full sample (Table 2). When factor loadings and thresholds (estimates of prevalence) for craving were allowed to vary across COGA, COGEND and FSCD, factor loadings remained consistently high while thresholds varied modestly across samples. A 4 degree of freedom test resulted in a significant chi-square difference (Δχ2= 27.8) although this difference was entirely attributed to the threshold differences. Furthermore, excluding craving from the factor analysis did not perturb the factor loadings for the DSM-IV dependence criteria.
