The field trialling of inventory scales reflecting variation in students' mathematics study and learning processes is described. These scales predict learning outcomes (final marks), but with differentiated patterns of relationship to those outcomes. In combination, the scales also detect cohorts of students at risk of study failure. The work reported is in the broader context of developing an individual-differences-based model of student learning. Although this model is sited specifically within mathematics learning, the methodology of its development is transferable to other discipline contexts. The trialled scales complement others already developed that reflect affective variation in students' mathematics study.