In order to determine cost efficiencies, fixed costs must be distinguished from variable costs, and the balance between the two understood. If the fixed costs of a technology project are high and its variable costs are low, then there will be cost advantages to scaling up. This is the case with general educational radio and television broadcasting. Programs such as Sesame Street and Discovery are more cost-efficient the larger their audience since the high cost of production is distributed over a larger viewer base while no staff expenditures are made for learner support.
On the other hand, the case of Telesecundaria in Mexico demonstrates that the impact of higher variable costs related to learner support may be offset if the scale of the project is sufficiently large to the point where per student costs compare favorably with those of traditional schools. Similarly, with the Interactive Radio Instruction project annual cost per student is estimated to fall from US$8.25 with 100,000 students to US$3.12 with 1,000,000. [58] Obviously, these economies of scale may be achieved only in countries with large populations.
Open and distance learning institutions have also achieved cost-effectiveness through economies of scale. Per student costs of the 11 mega-universities range from only 5% to 50% of the average of the traditional universities in their respective countries.