Factor Structure, Reliability, and Convergent Validity of an Ecological Momentary Assessment Binge-Eating Symptoms Scale.

Ecological momentary assessment (EMA) of binge-eating symptoms has deepened our understanding of eating disorders. However, there has been a lack of attention on the psychometrics of EMA binge-eating symptom measures. This paper focused on evaluating the psychometric properties of a four-item binge-eating symptom measure, including multilevel factor structure, reliability, and convergent validity. Forty-nine adults with binge-eating disorder and/or food addiction completed baseline questionnaires and a 10-day EMA protocol. During EMA, participants completed assessments of eating episodes, including four binge-eating symptom items. Analyses included multilevel exploratory factor analysis, computation of omega and intraclass correlation coefficients, and multilevel structural equation models of associations between contextual factors and binge-eating symptoms. A one within-subject factor solution fit the data and showed good multilevel reliability and adequate within-subjects variability. EMA binge-eating symptoms were associated with baseline binge-eating measures as well as relevant EMA eating characteristics: including greater unhealthful food and drink intake; higher perceived taste of food; lower likelihood to be planned eating; and lower likelihood of eating to occur at work/school and other locations and greater likelihood to occur at restaurants compared to home. In conclusion, the study findings support the psychometrics of a 4-item one-factor EMA measure of binge-eating symptoms.