Psychometric properties of the English version of the Anorectic Behavior Observation Scale: A collateral measure of symptoms in a sample of adolescents with anorexia nervosa and their parents

The Anorectic Behavior Observation Scale (ABOS) is a 30-item parent-reported measure of behaviors commonly observed in individuals with anorexia nervosa and other eating disorders. Anorexia nervosa is often accompanied by low insight into the severity of one’s own illness, thus, collateral information (e.g., parent or carer report) is useful to augment self-report measures in diagnostic settings. The factor structure of the ABOS has not been examined in an English-speaking sample. We evaluated the psychometric properties in a sample of 373 youth with anorexia nervosa and their parents (323 mothers and 235 fathers). Youth (13% male, 87% female) were aged between 10 and 22 years. We identified three Mokken scales via the maternal report of the ABOS, which we then replicated in the paternal report sample. The three identified scales (Mealtime Behaviors, Hyperactivity, Binge/Purge Behaviors) demonstrated acceptable internal consistency across both maternal and paternal report; however, we identified several concerns with the validity of the Hyperactivity scale. We found acceptable-good support for the utility of the ABOS (Factors 1 and 3) in correctly differentiating youth with anorexia nervosa from healthy controls, highlighting its potential benefit when diagnosing children or adolescents with anorexia nervosa. Our findings support the psychometric validity and reliability of a revised 2-factor ABOS in assessing anorexia nervosa symptomatology via parent report.