Order of factors in multiplying decimal numbers and gender differences: a comparison of tasks

Differential Item Functioning (DIF) analysis carried out within the framework of the Rasch model has been used to compare scholastic performance in sub-groups of students matched on ability and clustered by some features (such as, for example, gender). In this paper, we use DIF to understand if misconceptions about multiplication with decimal numbers act on boys and girls differently, i.e. if this can lead boys and girls to approach a mathematics item differently and, in some cases, to encounter it not successfully. We present empirical evidences revealed on a sample of 1647 students attending grade 8 of lower intermediate school. Results highlighted that misconception about multiplication of decimal numbers strongly disadvantages girls relative to boys and pose new research questions about mechanisms causing these results.