Background: Ecological momentary assessment (EMA) captures naturalistic experience in real time and holds promise to improve our understanding and treatment of youth psychopathology. While psychometric evaluation of EMA methods is crucial, particularly for use as a tool in clinical trials, research examining the reliability and validity of EMA items in youth is lacking. Method: This study evaluates EMA responses from 204 child and adolescent participants (M age = 12.54, 60.8% female), including 131 participants with an anxiety disorder and 73 participants with no psychiatric diagnosis. We assessed the within- and between-person variability, internal consistency, test-retest reliability, and convergent and discriminant validity of two EMA items probing anxiety symptoms; one positive affect item served as a comparison. Results: All psychometric properties of the anxiety items were at least satisfactory in youth with anxiety disorders. However, there was restricted variability and poor test-retest reliability in youth with no diagnosis. Discussion: These results might facilitate future clinical trials using EMA to investigate pediatric anxiety. Results also suggest that unique EMA items might be needed to reliably track anxiety in healthy youth. Future work should continue to examine the psychometric properties of EMA protocols before implementation in clinical trials. ClinicalTrials.gov identifier: NCT00018057.
Keywords: anxiety; ecological momentary assessment; psychometrics; youth.