An information processing apparatus (2000) acquires a plurality of data (10). The information processing apparatus (2000) generates a first matrix (20) representing groups, to which each data (10) belongs, in a classification according to a first reference. The information processing apparatus (2000) generates a second matrix (30) representing groups, to which each data (10) belongs, in a classification according to a second reference. The information processing apparatus (2000) computes a scalar product of the first matrix (20) and the second matrix (30), and, for each combination of the groups of the first reference and the groups of the second reference, computes the number of data (10) included in the combination.