The activity drivers in an activity-based costing
(ABC) system assign the activity costs to their final cost
objects (such as products, services, channels, customers,
and business sustaining). Ideally, they should be exactly
proportional. That is, if the quantity of an activity driver
increases 20%, its activity cost should also increase 20%.
This isn’t the case in poorly designed ABC systems. Again,
with correlation analysis, the quality of the activity driver
can be validated. If there is low correlation, then a new
activity driver can replace it and thus increase the cost
accuracy of the final cost object. This also provides better
insight as to what’s driving the costs.