Attribution of costs to joint products The previous chapter introduced activity based costing (Section 7.4) and the concept of cost objects (Section 7.5). Although a great deal ofattention has been paid to those institutions that teach only by distance means, historically dual-mode institutions that teach by both traditional and distance means have been far more common than pure distance teaching institutions. Such institutions offer a choice of learning modes to their customers, and in the process have diversified to serve two, often quite distinct, markets - on-campus and off-campus students. Recently; however, faced by increasingly acute pressures to reduce their unit costs, they have seen the utilization ofmaterials originally developed to teach distant students as a way of reducing their costs of teaching traditional campus-based students, by substituting resource-based learning (see Section 1.2) for face-to-face teaching - to the extent that, with the development of open and flexible learning, the distinction between traditional and distance forms of education is increasingly questionable (Rumble, 1994a: 15).