Once the costs of primary activities are determined, these costs can then be assigned to
products or other cost objects in proportion to their usage of the activity, as measured
by activity drivers. However, before any assignment is made, the cost objects must be
identified and the demands these objects place on the activities must be measured. Many
different cost objects are possible: products, materials, customers, distribution channels,
suppliers, and geographical regions are some examples. For our example, the cost objects
are products (services): intensive cardiology care, intermediate cardiology care, and
normal cardiology care. How to deal with cost assignment for other cost objects is discussed
in a later section. Activity drivers measure the demands that cost objects place
on activities. Most ABC system designs choose between one of two types of activity
drivers: transaction drivers and duration drivers. Transaction drivers measure the number
of times an activity is performed, such as the number of treatments and the number
of requests. Duration drivers measure the demands in terms of the time it takes
to perform an activity, such as hours of hygienic care and monitoring hours. Duration
drivers should be used when the time required to perform an activity varies from transaction
to transaction. If, for example, treatments for normal care patients average 10
minutes but for intensive care patients average 45 minutes, then treatment hours may
be a much better measure of the demands placed on the activity of treating patients
than the number of treatments