Activity-based costing

Traditionally, cost accountants had arbitrarily added a broad percentage of analysis into the indirect cost. In addition, activities include actions that are performed both by people and machine.

However, as the percentages of indirect or overhead costs rose, this technique became increasingly inaccurate, because indirect costs were not caused equally by all products. For example, one product might take more time in one expensive machine than another product—but since the amount of direct labor and materials might be the same, additional cost for use of the machine is not being recognized when the same broad 'on-cost' percentage is added to all products. Consequently, when multiple products share common costs, there is a danger of one product subsidizing another.

ABC is based on George Staubus' Activity Costing and Input-Output Accounting.[6] The concepts of ABC were developed in the manufacturing sector of the United States during the 1970s and 1980s. During this time, the Consortium for Advanced Management-International, now known simply as CAM-I, provided a formative role for studying and formalizing the principles that have become more formally known as Activity-Based Costing.[7]

Robin Cooper and Robert S. Kaplan, proponents of the Balanced Scorecard, brought notice to these concepts in a number of articles published in Harvard Business Review beginning in 1988. Cooper and Kaplan described ABC as an approach to solve the problems of traditional cost management systems. These traditional costing systems are often unable to determine accurately the actual costs of production and of the costs of related services. Consequently, managers were making decisions based on inaccurate data especially where there are multiple products.

Instead of using broad arbitrary percentages to allocate costs, ABC seeks to identify cause and effect relationships to objectively assign costs. Once costs of the activities have been identified, the cost of each activity is attributed to each product to the extent that the product uses the activity. In this way, ABC often identifies areas of high overhead costs per unit and so directs attention to finding ways to reduce the costs or to charge more for more costly products.

Activity-based costing was first clearly defined in 1987 by Robert S. Kaplan and W. Bruns as a chapter in their book Accounting and Management: A Field Study Perspective.[8] They initially focused on manufacturing industry where increasing technology and productivity improvements have reduced the relative proportion of the direct costs of labor and materials, but have increased relative proportion of indirect costs. For example, increased automation has reduced labor, which is a direct cost, but has increased depreciation, which is an indirect cost.

Like manufacturing industries, financial institutions have diverse products and customers, which can cause cross-product, cross-customer subsidies. Since personnel expenses represent the largest single component of non-interest expense in financial institutions, these costs must also be attributed more accurately to products and customers. Activity based costing, even though originally developed for manufacturing, may even be a more useful tool for doing this.[9][10]

Activity-based costing was later explained in 1999 by Peter F. Drucker in the book Management Challenges of the 21st Century.[11] He states that traditional cost accounting focuses on what it costs to do something, for example, to cut a screw thread; activity-based costing also records the cost of not doing, such as the cost of waiting for a needed part. Activity-based costing records the costs that traditional cost accounting does not do.

The overhead costs assigned to each activity comprise an activity cost pool.

Lean accounting methods have been developed in recent years to provide relevant and thorough accounting, control, and measurement systems without the complex and costly methods of manually driven ABC.

Lean accounting is primarily used within lean manufacturing. The approach has proven useful in many service industry areas including healthcare, construction, financial services, governments, and other industries.

Application of Theory of constraints (TOC) is analysed in a study[12] showing interesting aspects of productive coexistence of TOC and ABC application. Identifying cost drivers in ABC is described as somewhat equivalent to identifying bottlenecks in TOC. However the more thorough insight into cost composition for the inspected processes justifies the study result: ABC may deliver a better structured analysis in respect to complex processes, and this is no surprise regarding the necessarily spent effort for detailed ABC reporting.

When ABC is reportedly used in the public administration sector, the reported studies do not provide evidence about the success of methodology beyond justification of budgeting practise and existing service management and strategies.

Usage in the US Marine Corps started in 1999.[15][16][17][18]

Use of ABC by the UK Police has been mandated since the 2003-04 UK tax year as part of England and Wales' National Policing Plan, specifically the Policing Performance Assessment Framework.[19]

The potential problem with ABC, like other cost allocation approaches, is that it essentially treats fixed costs as if they were variable. This can, without proper understanding, give some people an inaccurate understanding which can then lead to poor decision making. For example, allocating PPE to individual products, may lead to discontinuation of products that seem unprofitable after the allocation, even if in fact their discontinuation will negatively affect the bottom line.

Even in ABC, some overhead costs are difficult to assign to products and customers, such as the chief executive's salary. These costs are termed 'business sustaining' and are not assigned to products and customers because there is no meaningful method. This lump of unallocated overhead costs must nevertheless be met by contributions from each of the products, but it is not as large as the overhead costs before ABC is employed.

Although some may argue that costs untraceable to activities should be "arbitrarily allocated" to products, it is important to realize that the only purpose of ABC is to provide information to management. Therefore, there is no reason to assign any cost in an arbitrary manner.

The prerequisite for lesser cost in performing ABC is automating the data capture with an accounting extension that leads to the desired ABC model. Known approaches for event based accounting simply show the method for automation. Any transition of a current process from one stage to the next may be detected as a relevant event. Paired events easily form the respective activity.

The state of the art approach with authentication and authorization in IETF standard RADIUS gives an easy solution for accounting all workposition based activities. That simply defines the extension of the Authentication and Authorization (AA) concept to a more advanced AA and Accounting (AAA) concept. Respective approaches for AAA get defined and staffed in the context of mobile services, when using smart phones as e.a. intelligent agents or smart agents for automated capture of accounting data .