MANAGEMENT
AND COST
ACCOUNTING
SIXTH EDITION
COLIN DRURY
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
Part Three:
Information for decision-making
Chapter Ten:
Activity based costing
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.1a
Generating relevant cost information
• There are 3 main reasons why a cost accumulation system is required to
generate relevant cost information:
1. Many indirect costs are relevant for decision-making:
• The cost of many joint resources (e.g.support function costs)fluctuate
according to the demand for them.
• Product introduction, discontinuation, redesign decisions determine the
demand for support function resources and thus future costs.
• Costs of support functions are difficult to trace directly to cost objects.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.1b
2. An attention directing system is required to identify potentially
unprofitable products that require more detailed special studies:
• It is not feasible to periodically undertake special studies for all products
or combination of product mixes.
3. Many product-related decisions are not independent:
• Focusing only on individual products ignores impact that the culmination
of many decisions will have on those joint resources that fluctuate
according to the demand for them.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.2
Types of cost systems
• Direct costing systems:
1 .Indirect costs are not assigned to cost objects so that only
contributions to indirect costs are reported.
2. Appropriate where the majority of costs are direct.
3. Require that indirect costs are incorporated at the special study stage.
• Traditional costing systems:
1. Use unsophisticated methods to allocate indirect costs to cost objects.
• ABC systems:
1. Use sophisticated methods to allocate indirect costs to cost objects.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.3
A comparison of traditional and ABC systems
• Both systems use the two-stage allocation process.
• In the first stage traditional systems tend to allocate costs to departments whereas
ABC systems allocate costs to activities: (ABC systems tend to have more cost
centres/cost pools)
• In the second stage traditional systems rely on a small number of volume-based
cost drivers (typically direct labour or machine hours) whereas ABC systems use
many second stage cost drivers.
• ABC systems seek to use only cause-and-effect cost drivers whereas traditional
systems often rely on arbitrary allocation bases.
• ABC systems tend to establish separate cost driver rates for support departments
whereas traditional systems merge support and production centre costs.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.4
A two-stage allocation process (traditional costing system)
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.5
The two-stage allocation process (ABC System)
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.6
The emergence of ABC systems
• Traditional systems were appropriate when:
1. Direct costs were the dominant costs
2. Indirect costs were relatively small
3. Information costs were high
4. There was a lack of intense global competition
5. A limited range of products was produced.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.7a
Errors from relying on misleading product costs
• Traditional costing systems use volume-based (e.g.direct labour and machine
hours) second stage drivers but if volume bases are not the cause of indirect costs
reported costs will be misleading.
Example
Products HV (a high volume product)and LV (a low volume product)are two of
several products produced by a company. HV is made in large batches and LV is
made in small batches. HV consumes 30%of DLH ’s and LV consumes 5% but
each product consumes 15%of the batch-related indirect costs.The traditional
system uses DLH ’s as the cost driver and the ABC system uses the number of
batches processed. All overheads (total =£1m)are batch-related .
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.7b
• Reported product costs:
• Traditional system reports misleading information —In the longer term overheads
will not decline by £300 000 if HV is discontinued.
• ABC allocates on a cause-and-effect basis and shows high level of resources
consumed by LV —The 2 costing systems report different messages (Traditional
=Drop HV ABC =Drop LV).
•Traditional system motivates the wrong strategy.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.8
Designing ABC systems
1. Identify the major activities that take place in an organization:
• The activities chosen should be at a reasonable level of aggregation
based on cost/benefit criteria.
• Choice of activities influenced by the total cost of theactivity centre and
the ability of a single cost driver to provide a satisfactory determinant of
the cost of the activity.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.8b
Designing ABC systems (contd.)
2. Assign costs to cost pools /cost centre for each activity:
• Costs assigned to activity cost pools will include direct and indirect costs.
• Resource cost drivers used to assign indirect costs.
• Reliability of cost information will be reduced if arbitrary allocations are
used to assign a significant proportion of costs to activities.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.8c
Designing ABC systems (contd.)
3. Determine the cost driver for each major activity:
• Drivers at this stage called activity drivers.They should:
(a) provide a good explanation of costs of each
activity pool.
(b) be easily measurable
(c) the data should be easy to obtain and identifiable with
the product.
• Activity cost drivers consist of three types (Transaction, duration and intensity
drivers).
4. Assign the cost of activities to products:
• The cost driver must be measurable so that it can be identified with individual
products.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.9a
Classification of activities
• Unit-level activities:
1.
2.
3.
Performed each time a unit of the product or service is produced.
Resources are consumed in proportion to the number of units produced or sold.
Examples —Direct materials and labour,energy costs and expenses consumed
in proportion to machine processing time.
• Batch-related activities:
1.
2.
3.
Performed each time a batch of goods is produced.
Costs vary with the number of batches made.
Examples include set-ups, purchase ordering and first-item inspection
activities.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.9b
Classification of activities contd.
• Product/service sustaining activities:
1.
2.
Performed to enable the production of individual products or services.
Examples include activities related to maintaining an accurate bill of materials,
preparing engineering change notices.
• Facility-sustaining (or business-sustaining) activities:
1.
2.
3.
Performed to support the organization as a whole.
Examples include plant management,property costs and salaries of general
administrative staff.
Common to all products and services –.not allocated to products/services.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.10
Activity-based profitability analysis
• Applies ABC hierarchical activity classification to profitability analysis.
• Used for attention directing —claimed provides more accurate information.
• Hierarchical approach can be applied to different cost objects (e.g.
products/services, customers, locations.)
• See sheet 11 for an illustration of the ABC hierarchical profitability analysis.
• Aim is to assign all organizational expenses to a particular hierarchical level
where cause-and-effect cost assignments can be established.
• The approach helps to identify the impact of resource consumption of adding or
dropping items at each level of the hierarchy.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.11
(Fig 10.2) An illustration of hierarchical profitability analysis)
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.12a
Resource consumption models
• ABC systems measure the cost of using resources and not the cost of supplying
resources:
Cost of resources
=
Cost of resources +
Cost of unused
Supplied
used
capacity
• Periodic financial statements measure the cost of resources supplied (i.e.15 000
orders at a cost of £300 000 in Example10.2).
• ABC systems measure the cost of resources used (i.e.13 000 orders at a cost of
£20 per order in Example 10.2).
• The difference between the cost of resources supplied and the cost of resources
used represents the cost of unused capacity (i.e.2 000 orders at £20 per order
=£40 000)
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.12b
• Unused capacity arises with committed resources because they must be
acquired in discrete amounts in advance of usage.
• With flexible resources supply can be continually adjusted to match exactly the
usage of resources.
• Managers make decisions that will result in a change of activity usage
(e.g.discontinuation decisions reduce cost of resources used and increase the
cost of unused capacity).
• Cash flow consequences will only arise if action is taken to remove unused
capacity by reducing spending on the supply of resources.
• The periodic reporting of unused capacity signals the need for a change in the
spending on the supply of resources.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.13
Example 10.2
(1) Resources supplied
10 staff at £30 000 per year
Cost driver
Annual quantity of cost driver
supplied:
(1 500 orders per employee)
Estimated cost driver rate
(2) Resources used
Estimated annual number of
orders to be processed
Estimated cost of resources
used assigned to parts/
materials
(3) Cost of unused capacity
Resources supplied (15 000)
–Resources used (13 000)
at £20 per order
= £300 000 annual activity cost
= Number of orders processed
= 15 000 purchase orders
= £20 per purchase order
(£300 000/15 000 orders)
= 13 000
= £260 000 (13 000*£20)
= £40 000 (2 000*£20)
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.14
Selecting the cost driver denominator level
• The correct denominator activity level to use is the level of capacity supplied
(practical capacity)and not the anticipated usage.
• Using anticipated usage in Example 10.2 would result in a cost driver rate of
£23.08 (£300 000/13 000)so that the cost of unused capacity will be hidden in the
cost driver rate rather than being separately reported.
• Using anticipated usage would result in high cost driver rates in periods of low
sales demand.
The ABC data base
• Ideally maintained at estimated standard costs and periodically reviewed.
• In addition a cost and profitability audit of a firm’s products,customers and sales
outlets should be periodically undertaken.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.15a
ABC cost management applications
• ABC can be used for a range of cost management applications besides
product costing.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury
10.15b
Criticisms of ABC
• ABC unit costs must be used with care —They can suggest an
inappropriate degree of variability.
• The concept of unused capacity within the resource consumption model
is questionable for physical resources.
• Reported costs may not significantly differ from a less costly traditional
system if indirect costs are a low proportion of total costs.
Management and Cost Accounting, 6th edition, ISBN 1-84480-028-8
© 2000 Colin Drury
© 2004 Colin Drury