Psychometric evaluation of a caregiver-report adaptation of the Overall Anxiety Severity and Impairment Scale (OASIS) for use with youth populations.

Background Despite progress in youth anxiety assessment, there is need for a measure that is simultaneously (a) free, (b) brief, (c) focused broadly on anxiety and avoidance severity, frequency, and interference, and (d) concerned with the past week. The adult overall anxiety severity and impairment scale (OASIS) was adapted to yield a caregiver-report of past week youth anxiety and interference (OASIS-Y). Methods In a sample of diverse youth seeking anxiety services (N = 132; 67% racial/ethnic minority) and their caregivers, analyses examined the OASIS-Y factor structure, internal consistency, and convergent and divergent validity. Hierarchical linear modeling in a participant subset examined OASIS-Y sensitivity to treatment-related change. Results OASIS-Y internal consistency was high and confirmatory factor analysis supported a single-factor structure similar to that found in adults. OASIS-Y convergent validity was supported by a medium-sized association with an established, commercially available measure of youth anxiety, and divergent validity was supported by the absence of unique associations with measures of youth attention and externalizing problems. In a sample subset, session-by-session OASIS-Y scores significantly declined across treatment, and declined at a steeper rate among treatment "responders" versus "non-responders," providing evidence of OASIS-Y sensitivity to treatment-related change. Limitations This study focused on a clinical sample and cannot speak to OASIS-Y performance in community settings. Shared method-variance may have also influenced findings. Conclusions This study offers the first psychometric evaluation of the OASIS-Y, and underscores the promising clinical utility of the measure for assessing past week youth anxiety and impairment and for supporting routine outcome monitoring.