title: Detecting and Explaining Aberrant Responding to the Outcome Questionnaire-45.
abstract: We applied item response theory based person-fit analysis (PFA) to data of the Outcome Questionnaire-45 (OQ-45) to investigate the prevalence and causes of aberrant responding in a sample of Dutch clinical outpatients. The [Formula: see text] person-fit statistic was used to detect misfitting item-score patterns and the standardized residual statistic for identifying the source of the misfit in the item-score patterns identified as misfitting. Logistic regression analysis was used to predict person misfit from clinical diagnosis, OQ-45 total score, and Global Assessment of Functioning code. The [Formula: see text] statistic classified 12.6% of the item-score patterns as misfitting. Person misfit was positively related to the severity of psychological distress. Furthermore, patients with psychotic disorders, somatoform disorders, or substance-related disorders more likely showed misfit than the baseline group of patients with mood and anxiety disorders. The results suggest that general outcome measures such as the OQ-45 are not equally appropriate for patients with different disorders. Our study emphasizes the importance of person-misfit detection in clinical practice.
authors.affiliation: School of Social and Behavioral Sciences, Tilburg University, Tilburg, Netherlands j.m.conijn@fsw.leidenuniv.nl.
authors.forename: Judith M
authors.initials: JM
authors.lastname: Conijn
authors.affiliation: School of Social and Behavioral Sciences, Tilburg University, Tilburg, Netherlands.
authors.forename: Wilco H M
authors.initials: WH
authors.lastname: Emons
authors.affiliation: Institute of Psychology, Leiden University, Leiden, Netherlands Research department, GGZ Noord-Holland-Noord.
authors.forename: Kim
authors.initials: K
authors.lastname: De Jong
authors.affiliation: School of Social and Behavioral Sciences, Tilburg University, Tilburg, Netherlands.
authors.forename: Klaas
authors.initials: K
authors.lastname: Sijtsma
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015982:Bias; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010043:Outcome and Process Assessment, Health Care; D011795:Surveys and Questionnaires
keywords: Outcome Questionnaire–45; aberrant responding; item response theory; outcome measurement; person-fit analysis