title: Two strategies for fitting real data to Rasch polytomous models.
abstract: A comparative study of the results provided by two strategies for fitting data to Latent Trait Theory Models has been performed. The first, called Total-Persons-Items (TPI), is structured in three phases: 1) assessment of item fit, 2) assessment of person fit; and finally, 3) overall fit of data to the models (items and persons). The second strategy, the Total-Items-Persons (TIP), changes the order of the phases: 1) assessment of person fit, 2) assessment of item fit and, 3) overall fit of data to the models. To verify the results of these two strategies, a set of 30 items, designed to measure religious attitude, was administered to a sample of 821 persons. The Latent Trait Theory Models used were the Partial Credit Model and the Rating Scale Model. The results underline an important difference between the two procedures: the TPI maximizes the number of persons with good fit and the TIP maximizes the number of items with good fit. Moreover, a procedure for controlling the sensitivity of fit to sample size is proposed.
authors: Area de Metodología de las Ciencias del Comportamiento, University of Almería, 04120 Almería, Spain. arojas@ual.es
authors: Antonio J
authors: AJ
authors: Rojas Tejada
authors: Andres
authors: A
authors: Gonzalez Gomez
authors: Jose L
authors: JL
authors: Padilla Garcia
authors: Cristino
authors: C
authors: Perez Melendez
mesh_terms: D000293:Adolescent; D000328:Adult; D001290:Attitude; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D010555:Personality Inventory / Q000706:statistics & numerical data*; D011594:Psychometrics / Q000706:statistics & numerical data; D012069:Religion and Psychology; D015203:Reproducibility of Results