Costruzione di una banca di item per la stima dell’abilità in matematica con prove adattative multilivello

The article describes the process of constructing an item bank aimed at implementing a computer-based MultiStage adaptive Test (MST) for the estimation of the mathematical ability of second-grade secondary school students. The multilevel adaptive tests are briefly introduced and the main steps of the bank construction process are described: the definition of the object of the test, the selection of the items downstream of the pretest operations, assuming that the data are adapted to a IRT model with one parameter, and the verification of the uni-dimensionality of the bank as a whole. The article also highlights some of the difficulties that can be encountered, such as being able to obtain adequate coverage of the test’s object or the range of the ability. The process described was overall successful and sufficiently general to be able to adapt to different needs, such as the construction of parallel linear tests or traditional adaptive tests (CAT – Computer-based Adaptive Test), aimed not only at summative or system assessment, but also, if the dimensions of the bank allow it, to formative evaluation.