title: Detection and validation of unscalable item score patterns using item response theory: an illustration with Harter's Self-Perception Profile for Children.
abstract: We illustrate the usefulness of person-fit methodology for personality assessment. For this purpose, we use person-fit methods from item response theory. First, we give a nontechnical introduction to existing person-fit statistics. Second, we analyze data from Harter's (1985) Self-Perception Profile for Children (Harter, 1985) in a sample of children ranging from 8 to 12 years of age (N = 611) and argue that for some children, the scale scores should be interpreted with care and caution. Combined information from person-fit indexes and from observation, interviews, and self-concept theory showed that similar score profiles may have a different interpretation. For some children in the sample, item scores did not adequately reflect their trait level. Based on teacher interviews, this was found to be due most likely to a less developed self-concept and/or problems understanding the meaning of the questions. We recommend investigating the scalability of score patterns when using self-report inventories to help the researcher interpret respondents' behavior correctly.
authors.affiliation: Department of Research Methodology, Measurement, and Data Analysis, University of Twente, Enschede, The Netherlands. r.r.meijer@gw.utwente.nl
authors.forename: Rob R
authors.initials: RR
authors.lastname: Meijer
authors.forename: Iris J L
authors.initials: IJ
authors.lastname: Egberink
authors.forename: Wilco H M
authors.initials: WH
authors.lastname: Emons
authors.forename: Klaas
authors.initials: K
authors.lastname: Sijtsma
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D015233:Models, Statistical; D009426:Netherlands; D010552:Personality Assessment / Q000706:statistics & numerical data*; D010555:Personality Inventory; D011594:Psychometrics / Q000379:methods; D015203:Reproducibility of Results; D012649:Self Concept