OBJECTIVES:  The DAS-A is an 8-item patient-reported instrument designed to detect daily changes of anxiety symptoms in patients with Generalized Anxiety Disorder (GAD) during the first week of treatment. This study compared the psychometric and measurement properties of an IVR version of the DAS-A with the original paper version. METHODS:  Adult patients with GAD were enrolled at the screening visit of a clinical trial. Treatment randomization occurred at day 0. Patients were scheduled to complete the IVR DAS-A from day -6 through day 7.  Paper-and-pencil DAS-A forms were completed by selected patients during clinic visits on days 0, 4 and 7.  Psychometric properties of both DAS-A forms were compared with respect to internal scale consistency (Chronbach’s alpha), item reliability (intraclass correlation coefficient; ICC), and mean score equivalence when both formats were administered within 24 hours of each other (paired t-tests).  RESULTS:  A total of 2804 IVR DAS-A assessments and 119 paper DAS-A forms were completed.  In 62 instances both formats were completed within 24 hours of one another.  Cronbach’s alpha across all IVR DAS-A administrations was 0.85; the mean ICC was 0.84 (95% CI = 0.83-0.85).  Cronbach’s alpha across all paper DAS-A administrations was 0.90; the mean ICC was 0.89 (95% CI = 0.86-0.92).  The mean (+ SD) IVR and paper DAS-A total scores were 58.97 (±20.09) and 60.91 (±21.00), respectively; this difference was not statistically significant, t = 1.89, p.=0.06. The correlation between the DAS-A total scores was 0.90, p.<0.001.  Comparisons between DAS-A formats at an item-by-item level found significant inter-method correlations (range 0.59 to 0.79); one item identified a potentially significant difference in mean score, t= 2.05, p.=0.04, but likely reflects Type I error inflation. CONCLUSIONS:  This analysis supports the equivalence of the IVR and paper DAS-A formats for measuring daily changes of anxiety symptoms in patients with GAD.