indirect and support costs, which cannot directly reflect variation from final cost objects, and there are also cost object–to–cost object assignments. An example of the latter assignment type is the cost to process a special order (versus a stan- dard order), traced to a specific customer or a group of customers consuming a unique quantity and mix of products, services, or outputs.
The model in Figure 12.2 is analogous to Charles Darwin’s model for the evo- lution of the species. The left graphic is like a single-celled paramecium or amoeba. The middle graphic is analogous to reptiles, amphibians, and snakes.
The right graphic is like humans beginning to walk upright.
In Figure 12.2 the left graphic is primitive. It represents traditional account- ing’s cost allocationmethod, which simply and arbitrarily redistributes the source costs into destinations such as product costs, without regard to logical causality.
Many financial controllers still allocate costs this way.1But without any causal re- lationship, there is an expected, undesirable error in calculating the costs of cost objects. The results are inaccurate costs. The financial controllers who continue to allocate costs this way are misleading their end-users with flawed data.
The middle graphic in Figure 12.2 represents the ABM two-stage cost alloca- tion model, in which the expenditures for resources are assigned at the work ac- tivity level, not at a department level (i.e., using verb-adjective-noun grammar to define activities). But this method is too simplistic to be adequate.
The right-hand side of Figure 12.2 symbolizes the activity-based costing verti- cal cost assignment as a multistage cost assignment network with an expanded 106 LEVERAGING FINANCIAL ANALYTICAL FACTS AND TRUTHS
Traditional Costing Resources
Cost Objects
ABC (Simple, Minimal) Resources
Activities
Cost Objects
ABC (Multidimensional,
Arterial) Resources
Activities
Products Orders/
Shipments Customers Cost
Objects
Attributes
Traditional Costing
Simple
ABC Expanded ABC
Consumed by
Consumed Consumed by
by
Consumed by Allocated
to
Figure 12.2 Darwin’s Evolution of Cost Accounting Methods ccc_cokins_12_98-109.qxd 1/14/04 10:28 AM Page 106
ACTIVITY-BASED MANAGEMENT MODEL DESIGN AND PRINCIPLES 107
Two Alternative Equations for Costing Activities and Cost Objects There are two alternative approaches for computing activity costs and the costs of cost objects, such as products. The two approaches differ based on which data one prefers to collect or calculate, and on how an organization prefers to use feedback data to control its costs. The two approaches are as follows:
1. Activity driver equations.First, activity costs are derived (via surveys, timesheets, estimates, etc.). Then the quantity, frequency, or intensity of the activity driver is collected per each activity. A unit cost rate per each activity driver is computed and then applied to all of the cost ob- jects, based on their unique quantity of the activity driver events (e.g., number of invoices processed). This is recalculated for each time pe- riod for each work activity.
2. Cost object equations. This approach begins with an in-depth time measurement study of work tasks and processes. In the study, the per- unit time elements for various (and optional) processing steps for each product (or product group) and each type of order are surveyed with deep time studies. Then each product and type of order is profiled with an equation specifying the sum of the number of transactions (e.g., events) for each product or type of order. Finally, the quantity of the products and order types is counted for the period and back-flushed against each product’s or order’s standard minutes-per-event to calcu- late an activity cost. This activity cost assumes the standard rate and is not the actual activity cost. The premise that this assumption is accept- able is that micromeasured activities do not vary much over time.
What drives requirements for expenses is the varying mix and volume of products and type of orders.
Figure 12C displays where these two approaches are located with respect to the ABM cost assignment network and how they differ. The activity driver equation approachsolves for cost of the cost objects by measuring or estimat- ing activity costs and tracing them per events (i.e., activity driver quantities).
In contrast, the cost object equation approachbegins with product and order type profiles, collects volume and mix data, and then solves for the activity costs, assuming the standard times are correct and incurred. It starts with a low level of characteristics of the cost object. This approach appears to reverse- calculate to determine the activity costs.
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108 LEVERAGING FINANCIAL ANALYTICAL FACTS AND TRUTHS
Two Alternative Equations for Costing Activities and Cost Objects (Continued)
Theactivity driver equation approachsolves for the activity driver rate by assuming that data for the other two factors can be collected or reasonably es- timated. The cost object equation approachsolves for the activity cost, at a standard cost, by presuming that processing times for each product’s (i.e., out- put) characteristics have been measured, profiles for each product config- ured, and then the product mix volumes reported. The superior ABM software can compute costs in both directions.
Regardless of which equation-based approach is used, be cautious to first recognize the primary reasons you may be pursuing ABM data. Then, pre- suming there will be some interest in using the ABM for operational cost con- trol and feedback, be clear what type of feedback costs you will be more interested in.
Resources
Activities
Activity Drivers
Event-Based Costing:
(qty x rate) = cost or
rate = (cost / qty)
?
?
Two knowns solve for the unknown dependent variable.
ActivityEquations Cost Objects Equations
Cost Objects
Resource Drivers
Figure 12C Two Cost Equation Approaches ccc_cokins_12_98-109.qxd 1/14/04 10:28 AM Page 108
multistage structure that allows for intermediate activities and activity drivers, and cost objects being traced into other cost objects (i.e., the predator food chain).
This graphic is labeled as the arterial ABM model to distinguish it from the obso- lete two-stage ABM model. Thus, the three modules of the ABM model have now matured to become a multistage network of activities and objects. This cost as- signment network has the flexibility to link resources to their cost objects—and the tracing relies on cause-and-effect relationships. Hence, the complete cost as- signment network leads to much greater accuracy of cost object costs.
In summary, the evolution of the vertical activity-based costing cost reassign- ment network starts with the simplistic and arbitrary allocations of the traditional accounting system, and it ends with a multistage network of costs flowing through activity-based costing’s three cost modules. This multistage arterial costing net- work is capable of detecting greater diversity and variation not only in product costs but also in all final cost objects, including different types of customers.
NOTE
1. “The State of Management Accounting: The Ernst & Young and IMA Sur- vey (2003),” at www.imanet.org.
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