Analisi di un insieme di item, indicatori della dimensione "Mental Health Locus of Origin". Metodi della Teoria Classica e della Teoria dei Tratti latenti

In this paper a set of items indicators of the dimension named "Mental Health Locus of Origin" is examined according to two different approaches. Data obtained from the applicatin of the "Mental Health Locus of Control Scale" to 230 subjects aged between 19 and 35 years, are elaborated on the base of two methods which belong respectively to the classic test theory and to the latent trait theory. Both methods have evidenced a group of items which are not consistent within the dimension. The approach based on the latent trait theory is taken into particular consideration; two extensions of the simple logistic model by Rasch are applied to the data: the "rating scale model" and the "dispersion location model". The advanteges of the latent trait theory perspective are discussed.