For example, with the 2-product, 12-activity example of Exhibit 4-16, a reduced
system of two drivers can always be identified that will achieve the same cost assignment
as the larger 12-driver system.5 Thus, once a larger system has been identified, a
smaller system with the same accuracy can be created. To illustrate, consider two activities
from Exhibit 4-16, testing products and purchasing materials. The consumption
ratio vectors for the two activities are (0.6, 0.4) and (0.2, 0.8), respectively. For each
product, the global consumption ratio can be expressed as a weighted combination of
the consumption ratios for the two activities