Dimensionality and Item-Level Analysis of the DAST-10 in a Sample of HIV Patients with a History of Problematic Substance Use

Objectives This study sought to evaluate the dimensionality of the DAST-10 scores and to investigate how well the items identify a respondent’s substance use severity.Method This work uses data provided by 810 participants from Project HOPE. Participants were recruited while in a hospital and had to have a recent history of problematic substance or alcohol use. Parallel and ordinal confirmatory factor analysis were used to evaluate dimensionality and a two-parameter logistic model was used to study how well the items identify a respondent’s use severity.Results Analyses suggested that one factor may underly the associations among the items. The two-parameter logistic model yielded location estimates ranging from −1.78 to 1.06 and discrimination estimates from 0.84 to 2.71.Conclusion Users are encouraged to treat the DAST-10 as a unidimensional scale and using the measure with respondents of increasingly low or severe levels of problematic substance use may yield imprecise measurements.