he costs of some activities are not always related to a unit of a product, but are
attached to a higher level, such as to a batch of products or to a certain product directly [43].
In such cases, assigning the cost to each unit of product will give erroneous information.
Cooper and Kaplan categorize activities into four levels according to the types of costs
assigned to the products: unit-level activities, batch-level activities, product-sustaining
activities, and facility-sustaining activities (See Appendix G) [13].
The costs of unit-level activities are assigned in proportion to the number of
products produced. Therefore, as the volume of production increases, the costs of this kind
of activities increase [43].
Batch-related activities are performed every time a batch of products is processed. In
this kind of activity, resource consumption is proportional to the number of batches
processed. The cost drivers used in batch-related activities are called “batch drivers.” A
batch driver assigns the cost of an activity to a batch [13].
Product-sustaining activities are performed in order to continue to produce and sell
individual products. The costs of these activities can be traced to each pr