Activity based costing
is a costing system based on a number of activities (cost drivers) that affect the product rather than the use of plantwide or department overhead rates.
Traditional costing systems (normal absorption costing) are
primarily for external users (e.g., the financial statements and tax returns).
For external reporting,
ALL manufacturing costs must be assigned to a product and non-manufacturing costs (S&A exp.) are not assigned to products even if caused by a product.
There are five major differences between a traditional and an activity-based costing system.
Non-manufacturing costs may be assigned to products. Ex.: sales commissions are not included in product costs in a traditional environment whereas they could be in an ABC system.
Overhead costs are assigned in a 2 step process.
An ABC system will typically shift costs away from
from high volume products that are produced in large batches to low volume products that are produced in small batches.
Benefits of ABC systems
are that they provide more accurate cost information. It helps to focus the managers on the costs that they can control.
Limitations
include the high cost of measurement. Companies that do not have diverse products may not benefit as much from ABC. (Diverse products consume resources differently). It requires a long-term commitment by all areas of the business.
ABC does not conform to GAAP
. As a result, companies will need 2 cost systems. It may be used for internal decision making and pricing purposes.