Item 1 failed to load on the hypothesized subscale but loaded on all six other subscales. This may indicate that changes in appetite or interest in food may have been a sign of general psychological distress in this sample of treatment-seeking smokers rather than a reflection STI 571 of the loss of the appetite-suppressant side effect of nicotine. Although item 7 loaded on the sadness subscale, it also loaded on the anxiety, anger, and craving subscales. Given the wording of the item and the fact that it is reverse scored, this item may better tap positive affect in general, which might be expected to relate to a number of negative emotions and craving. Multiple-group analysis of the modified 26-item WSWS displayed total measurement invariance across African American, White, and Latino smokers in treatment, suggesting several conclusions.
First, it supports configural invariance. That is, the same factors and same pattern of factor loadings exist across racial/ethnic groups. This finding suggests that the WSWS taps the same constructs for all three racial/ethnic groups. Second, results indicate that the factor loadings of each item are equal across racial/ethnic groups (i.e., metric invariance), indicating that each item is equally representative of the factor on which it loads across groups, and thus, the items are interpreted similarly across groups. Third, results support the presence of scalar invariance, in which item intercepts are equal across racial/ethnic groups. This finding indicates that not only do the items share the same metric across groups but also share the same start point or origin.
Thus, a given factor score represents the same level of symptom severity across the three racial/ethnic groups. The presence of metric and scalar invariance indicates that factor variances, covariances, and means can be compared across groups. Finally, results suggest that the item residual variances of the WSWS are equal across racial/ethnic groups. This indicates that items are equally precise across groups, and thus, observed scale scores can be compared across groups. Observed scale scores of the WSWS were also examined for predictive equivalence using short-term (week 1 and week 2) relapse as the criterion. Results demonstrated predictive equivalence of the total WSWS scale and all subscales across racial/ethnic groups with the exception of the sleep subscale. The sleep subscale was predictive of relapse for Whites, but not for African Americans or Latinos. Thus, the current study provides the first evidence that the WSWS sleep subscale predicts relapse differentially across racial/ethnic groups. However, evidence of predictive bias was found only Entinostat at week 1.