A Multidimensional IRT approach to analyze learning achievement of Italian students

In the field of educational measurement, it often happens that tests consist of different subscales involving explicitly several dimensions. With the aim of estimating the test item psychometric properties and the candidate ability, item response theory (IRT) models are often used with multidimensional structure. In this work, a comparison among multidimensional models with different ability structures is conducted in a case study. In particular, data from Italian student assessments conducted at the end of the lower secondary school by INVALSI are taken into account.