The time spent on each activity is the driver used to assign the labor costs to the
activity. If the time spent is 100 percent, then labor is exclusive to the activity, and direct
tracing is the cost assignment method (such as the labor cost of supervision). On
the other hand, the nursing resource is shared by several activities, and driver tracing
is used for the cost assignment. These drivers are called resource drivers. Resource drivers
are factors that measure the consumption of resources by activities. To illustrate,
assume the general ledger reveals that the supervisor’s salary is $50,000 and that the
salaries of the nurses total $300,000. The amount of nursing cost assigned to each activity
is as follows