Binomial Mixture Modeling of University Credits

What is it about?

The paper reviews finite mixture models for binomial counts with concomitant variables. These models are well known in theory, but they are rarely applied. We use a binomial finite mixture to model the number of credits gained by freshmen during the first year at the School of Economics of the University of Florence. The finite mixture approach allows us to appropriately account for the large number of zeroes and the multi-modality of the observed distribution. Moreover, we rely on a concomitant variable specification to investigate the role of student background characteristics and of a compulsory pre-enrolment test in predicting gained credits. In the paper we deal with model selection, including the choice of the number of components, and we devise numerical and graphical summaries of the model results in order to exploit the information content of the concomitant variable specification. The main finding is that the introduction of the pre-enrolment test gives additional information for student tutoring, even if the predictive power is modest.

Featured Image

Why is it important?

We show that binomial mixture modelling is a flexible, helpful tool in situations where it is hard to specify a parametric distribution for counts with a fixed maximum.