| pubmed-article:12011498 | pubmed:abstractText | 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. | lld:pubmed |
