the terms fixed cost and variable cost only have meaning when related to some output measure or driver.Therefore, we must first determine the underlying activities and the associated drivers that measure the capacity of an activity and its output.For example, materials handling may be measured by the number of moves; shipping goods may be measured by the units sold; and laundering hospital linen may be measured by the pounds of laundry. The choice of driver is tailored not only to the particular firm but also to the particular activity or cost being measured.