MANAGEMENT ACCOUNTING
CONCEPTS AND TECHNIQUES
By Dennis Caplan, University
at Albany (State University of New York)
CHAPTER
11: Activity-Based Costing
Chapter
Contents:
- Background
- Apparel factory example of two-stage ABC allocations
- Cost hierarchy
- Milwood Mills
- ABC in the service sector
- ABC implementation issues
- Exercises and problems
Background:
Activity-based costing (ABC) is a better, more accurate way of allocating overhead.
Recall the steps to product costing:
1. Identify the cost object;
2. Identify the direct costs associated with the cost object;
3. Identify overhead costs;
4. Select the cost allocation base for assigning overhead costs to the cost object;
5. Develop the overhead rate per unit for allocating overhead to the cost object.
Activity-based costing refines steps #3 and #4 by dividing large heterogeneous cost pools into multiple smaller, homogeneous cost pools. ABC then attempts to select, as the cost allocation base for each overhead cost pool, a cost driver that best captures the cause and effect relationship between the cost object and the incurrence of overhead costs. Often, the best cost driver is a nonfinancial variable.
ABC can become quite elaborate. For example, it is often beneficial to employ a two-stage allocation process whereby overhead costs are allocated to intermediate cost pools in the first stage, and then allocated from these intermediate cost pools to products in the second stage. Why is this intermediate step useful? Because it allows the introduction of multiple cost drivers for a single overhead cost item. This two-stage allocation process is illustrated in the example of the apparel factory below.
ABC focuses on activities. A key assumption in activity-based costing is that overhead costs are caused by a variety of activities, and that different products utilize these activities in a non-homogeneous fashion. Usually, costing the activity is an intermediate step in the allocation of overhead costs to products, in order to obtain more accurate product cost information. Sometimes, however, the activity itself is the cost object of interest. For example, managers at Levi Strauss & Co. might want to know how much the company spends to acquire denim fabric, as input in a sourcing decision. The “activity” of acquiring fabric incurs costs associated with negotiating prices with suppliers, issuing purchase orders, receiving fabric, inspecting fabric, and processing payments and returns.
Apparel
Factory Example of Two-Stage ABC Allocations:
Assume that an apparel factory uses forklifts in only two departments:
The first department is Receiving, where large rolls of fabric are unloaded from semi-trailers and moved into storage, and later moved from storage to the cutting room.
The second department is Shipping, where cartons of finished pants are staged and then loaded onto semi-trailers for shipment to the warehouse.
Costs associated with operating these forklifts consist of the following:
|
Forklift costs: Operator salaries Maintenance Depreciation expense Other Total forklift costs All other overhead Total overhead for the factory |
$ 80,000 8,000 7,500 2,500 $ 98,000 1,400,000 $1,498,000 |
The factory operates two production lines. One line is for jeans, which are made from denim fabric. The other production line is for casual slacks, which are made from a cotton-twill fabric. Operational data for the month is as follows:
|
|
Jeans |
Casual Slacks |
Total |
|
Units produced Direct labor hours Rolls of fabric Cartons shipped |
420,000 70,000 1,750 52,500 |
200,000 40,000 640 20,000 |
620,000 110,000 2,390 72,500 |
The factory ships product to the company’s warehouse, not directly to customers. Hence, to facilitate stocking at the warehouse, each carton is packed with jeans or casual slacks, but not both. An examination of the information in the above table reveals that a carton holds more slacks than jeans, and that fewer pants are cut from a roll of denim fabric than from a roll of cotton-twill. These operational statistics are driven by the fact that denim is a heavier-weight fabric than cotton-twill, and hence, it is bulkier. The data also indicate that more direct labor minutes are required for a pair of slacks than for a pair of jeans, which reflects greater automation on the jeans production line.
Traditional costing
Under a traditional costing system, forklift costs are pooled with all other overhead costs for the factory (electricity, property taxes, front office salaries, etc.), and then allocated to product based on direct labor hours (sewing operator time) for each product.
Overhead rate under traditional costing:
|
Total overhead costs Quantity of allocation base (direct labor hours) Overhead rate per direct labor hour of which the following is due to forklift costs: Forklift overhead Quantity of allocation base (direct labor hours) Overhead rate for forklift costs per direct labor hour |
$ 1,498,000 ÷ 110,000 $ 13.62 $ 98,000 ÷ 110,000 $ 0.8909 |
Forklift overhead applied to product using traditional costing:
|
|
Jeans |
Slacks |
|
Overhead rate Quantity of allocation base (direct labor hours) Forklift costs allocated Units produced Approximate cost per unit |
$ 0.8909 x 70,000 $ 62,363 420,000 $0.15 |
$ 0.8909 x 40,000 $ 35,636 200,000 $0.18 |
Note that all forklift overhead is allocated: $62,363 + $35,636 = $97,999 (the difference due to rounding of the overhead rate).
If the casual slacks product manager asks why her product incurs more forklift costs on a per-unit basis than jeans, even though casual slacks use a lighter-weight fabric, the answer is that her product uses more direct labor per unit, which perhaps is not a very satisfying explanation from her perspective.
Activity-based costing
An ABC system might first allocate forklift costs into two cost pools: one for the Receiving Department and one for the Shipping Department. Then costs from each of these two departments would be allocated to the two product lines.
ABC first-stage allocation
The first-stage allocation might use an estimate of the amount of time the forklifts spend in each department. A one-time study indicates that forklifts spend approximately 70% of their time in the Shipping Department and 30% of their time in the Receiving Department. An additional benefit of ABC is that if this information were collected periodically, the managers of these two departments might be more willing to share the forklifts with each other, since the reported costs of each department would then depend on the time the forklifts spend in that department. In any case, the 70/30 allocation results in the following first-stage allocation:
30% of $98,000 = $29,400 is allocated to the Receiving Department
70% of $98,000 = $68,600 is allocated to the Shipping Department
ABC second-stage allocation
|
|
Receiving |
Shipping |
|
Total costs Quantity of allocation base Overhead rate Allocation to Jeans Overhead rate Quantity of allocation base Allocation to Slacks Overhead rate Quantity of allocation base |
$29,400 ÷ 2,390 rolls $12.30 per roll $12.30 per roll x 1,750 rolls $21,525 $12.30 per roll x 640 rolls $7,872 |
$68,600 ÷ 72,500 cartons $0.946 per carton $0.946 per carton x 52,500 cartons $49,665 $0.946 per carton x 20,000 cartons $18,920 |
Total forklift costs allocated to each product:
|
|
Jeans |
Slacks |
Total |
|
From Receiving |
$21,525 |
$ 7,872 |
$29,397 |
|
From Shipping |
49,665 |
18,920 |
68,585 |
|
Total |
$71,190 |
$26,792 |
$97,982 |
|
Units Produced |
420,000 |
200,000 |
|
|
Approximate Cost per unit |
$0.17 |
$0.13 |
|
The $18 difference between total costs allocated of $97,982 and the original costs of $98,000 is due to rounding.
The first-stage allocation allows the second-stage to allocate forklift costs to product using rolls of fabric as the allocation base in Receiving, and cartons of pants as the allocation base in Shipping. Since there are no rolls of fabric in the shipping department, and no cartons in the Receiving Department, without the first stage allocation, there would be no obvious choice of an allocation base that would capture the cause-and-effect relationship between the costs of operating the forklifts, and the utilization of forklift resources by each product in the two departments.
Conclusion
The traditional costing method allocates more forklift costs to slacks than to jeans on a per-unit basis because casual slacks require more sewing effort. ABC allocates more forklift costs to jeans than to casual slacks, on a per-unit basis, which is intuitive because denim is a heavier-weight fabric than cotton twill.
Cost
Hierarchy:
In ABC, cost pools are often established for each level in a hierarchy of costs. For manufacturing firms, the following cost hierarchy is commonly identified:
Unit-level costs: For any given product, these costs change in a more-or-less linear fashion with the number of units produced. For example, fabric and thread are unit-level costs for an apparel manufacturer: if the company wants to double production, it will need twice as much fabric and thread.
Batch-level costs: These costs change in a more-or-less linear fashion with the number of batches run. Machine setup costs are often batch-level costs. The time required to prepare a machine to run one batch of product is usually independent of the number of units in the batch: the same time is required to prepare the machine to run a batch of 100 units as a batch of 50 units. Hence, batch-level costs do not necessarily vary in a linear fashion with the number of units produced.
Product-level costs: These costs are usually fixed and direct with respect to a given product. An example is the salary of a product manager with responsibility for only one product. The product manager’s salary is a fixed cost to the company for a wide range of production volume levels. However, if the company drops the product entirely, the product manager is no longer needed.
Facility-level costs: These costs are usually fixed and direct with respect to the facility. An example is property taxes on the facility, or the salaries of front office personnel such as the receptionist and office manager.
One reason why ABC provides more accurate product cost information is that traditional costing systems frequently allocate all overhead, including batch-level, product-level, and facility-level overhead, using an allocation base that is appropriate only for unit-level costs. The better information obtained from explicitly incorporating the cost hierarchy is illustrated in the following example:
Milwood Mills:
Milwood
Mills makes decorative woodcut prints for sale to restaurants. Its
|
|
Bull |
Dogs |
Total |
|
Number of woodcuts produced Direct materials costs Direct labor costs Number of batches Total overhead Batch setup costs (included in total overhead) |
500 $2,500 $1,400 10 |
1,500 $3,300 $1,600 30 |
2,000 $5,800 $3,000 40 $42,000 $12,000 |
The traditional costing system allocates all overhead based on number of units produced. This method allocates overhead of $21 ($42,000 ÷ 2,000 units) to each Bull and Matador woodcut and to each Dogs Playing Poker woodcut, of which $6 ($12,000 ÷ 2,000 units) represents batch setup costs.
The manager of the Bull and Matador production line develops a technique for doubling the batch size on her line without incurring any additional costs. Hence, she can now make 500 woodcuts per month using only 5 setups. She thinks this should cut her batch setup costs in half. She reasons as follows:
What “drives” batch setup costs? It is the number of batches. The cost per batch is $300. ($300 per batch x 40 batches = $12,000, which agrees to the monthly information provided above.) Using the new batch size, the batch setup cost is still $300, but instead of spreading this $300 over 50 units, the $300 will be spread over 100 units, lowering my per-unit batch setup cost from $6 to $3, and lowering my total unit cost by $3.
However, the following month, after implementation of the manager’s increased batch size, reported costs are as follows: Total overhead drops by $1,500, which represents the cost savings from eliminating five batch setups for the Bull and Matador production line. Hence, total overhead drops from $42,000 to $40,500. The traditional costing system allocates this $40,500 to 2,000 units as $20.25 per unit. This new overhead rate represents a savings of $0.75 per unit for every woodcut: every Bull and Matador woodcut, and every Dogs Playing Poker woodcut. The manager of the Bull and Matador production line is disappointed. Her reported costs did not decrease by as much as she had anticipated, because most of the benefit from the reduction in batch setups has been allocated to the Dogs Playing Poker production line.
An ABC system that explicitly recognizes the cost hierarchy would correct this problem. Under the old production process, ABC would have allocated costs as follows: The cost pool for batch setup costs was previously $12,000, which would have been allocated to the two product lines based on the number of batches run by each line:
Overhead rate = total batch setup costs ÷ total number of batches
= $12,000 ÷ 40 batches = $300 per batch
Batch setup costs of $300 per batch
x 10 batches = $3,000 would have been allocated to Bull,
x 30 batches = $9,000 would have been allocated to Dogs.
In a second-stage allocation, the $3,000 allocated to the Bull and Matador production line would have been allocated to 500 units for a cost of $6 per woodcut. This allocation is the same as under the traditional costing system only because the batch size of 50 woodcuts per batch was originally the same on both production lines.
After the batch size is increased for Bull and Matador, production information is as follows:
|
|
Bull |
Dogs |
Total |
|
Number of woodcuts produced Direct materials costs Direct labor costs Number of batches Total overhead Batch setup costs (included in total overhead) |
500 $2,500 $1,400 5 |
1,500 $3,300 $1,600 30 |
2,000 $5,800 $3,000 35 $40,500 $10,500 |
Now ABC would allocate costs as follows:
In the first stage: $10,500 ÷ 35 batches = $300 per batch (same as before).
$300 per batch x 5 batches = $1,500 to Bull and Matador (50% less than before),
$300 per batch x 30 batches = $9,000 to Dogs Playing Poker (same as before).
In the second stage, the $1,500 is allocated to the 500 Bull and Matador woodcuts, for $3 per woodcut. This $3 per woodcut reflects the cost savings originally anticipated by the manager of the Bull and Matador production line. The cost per woodcut for Dogs Playing Poker remains unchanged ($9,000 ÷ 1,500 units = $6), which is appropriate because nothing has changed on the Dogs Playing Poker production line.
ABC
in the Service Sector:
ABC is as important to companies in the merchandising and service sectors as to manufacturing companies. In fact, although the origination of ABC is generally ascribed to manufacturing companies in the 1980s, by then hospitals were already allocating overhead costs to departments and then to patient services using methods similar to ABC. Hospitals were required to implement relatively sophisticated allocation processes in order to comply with Medicare reimbursement rules. After its inception in the 1960s, Medicare established detailed rules regarding how overhead costs should be grouped into cost pools, and the choice of appropriate allocation bases for allocating overhead costs to departments and then to patients. Within these rules, hospitals were able to maximize revenues by shifting costs from areas such as pediatrics, labor and delivery, and maternity (which have low rates of Medicare utilization) to the intensive care unit, the critical care unit, and surgery (which have higher rates of Medicare utilization). Other non-manufacturing industries that have benefited from ABC include financial services firms and retailers.
ABC
Implementation Issues:
Another refinement in product costing that often accompanies implementation of ABC focuses on step #2 of the five-step product costing sequence: “identify the direct costs associated with the cost object.” The refinement involves the following. For a given cost object, the company attempts to identify costs currently treated as overhead that have not been—but can be—traced directly to the cost object. In other words, costs are moved from the overhead cost pool to the direct cost category. For example, an accounting firm might take certain office-support expenses formerly treated as overhead, such as printing and copying, and start tracking and assigning these costs to specific jobs (audits, tax engagements, etc.) for internal reporting and profitability analysis (but not necessarily for client billing purposes).
The successful implementation of ABC usually requires participation by managers from non-accounting functions, such as production and marketing. Because ABC focuses on activities, and activities often cut across departments and functional areas, implementing ABC can improve lines of communication and cooperation within the company. On the other hand, more accurate cost allocation does not, by itself, reduce costs. The initial move from a traditional costing system to ABC usually shifts overhead costs from some products to other products, with some managers “winning” and some “losing.” Some companies have found that hiring an outside consulting firm to assist with the ABC adoption facilitates obtaining “buy-in” by managers and employees throughout the company. Perhaps partly for this reason, ABC implementation has become an important consulting product for accounting firms and for many consulting firms.
Although ABC should provide the company more accurate information, it is not a panacea; some companies that invested time and money implementing ABC did not realize the benefits they expected. Some of these companies have reverted to simpler, more traditional costing systems.
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Management
Accounting Concepts and Techniques; copyright 2006; most recent update: November
2010
For a printer-friendly version, contact Dennis Caplan at dcaplan@uamail.albany.edu