Activity-based Costing (ABC) entstand in den USA vor allem aufgrund der Unzulänglichkeiten der amerikanischen Kostenrechnung im Fertigungsbereich. Die Overhead wurden auf Basis der direkten Lohnstunden, Maschinenstunden oder der Materialkosten auf die Produkte verrechnet. Mit Hilfe dieser volumenorientierten Bezugsgrößen konnten den Produkten jedoch nicht alle Kosten verursachungsgerecht zugeordnet werden. Im Mittelpunkt der ersten Ansätze des ABC standen deshalb die Gemeinkosten der Fertigung und deren Verrechnung auf die Produkte.
The 1985 essay "The hidden factory" by Miller and Vollmann provided the decisive impetus for the development of the ABC. They presented the results of an empirical study according to which in the period from 1855 to 1975 the share of overhead costs in the value added in American industry had steadily increased, while the share of direct wage costs continued to decline. Because of this development, Miller and Vollmann felt it was necessary to turn away from the focus on “visible operations”, ie direct production, and to take a closer look at the indirect areas, the so-called “hidden factory”.
Die treibende Kraft der Gemeinkosten seien „transacions, not physical products“. Eine erste konzeptionelle Umsetzung der Vorschläge von Miller und Vollmann vollzogen Johnson und Kaplan 1987 in ihrem Buch „Relevance Lost: The Rise and Fall of Management Accounting“. Sie kritisierten dabei insb. die aus der Verwendung ungeeigneter Bezugsgrößen in der Full cost accounting resultierende Quersubvention zwischen den Produkten. Johnson und Kaplan entwickelten daraufhin ein Konzept zur verursachungsgerechteren Verrechnung der Gemeinkosten der fertigungsnahen Bereiche auf die Produkte. Im Anschluss an ihr Buch konkretisierten und erweiterten Johnson und Kaplan zusammen mit Cooper das Konzept der prozessorientierten Gemeinkostenverrechnung und prägten die Bezeichnung „Activity-based Costing“, die sich heute in der anglo-amerikanischen Literatur und Praxis durchgesetzt hat.
All of the ABC's approaches assume that a company's resources are used to carry out activities that in turn serve to generate services. The cost of the resources is allocated to the activities that have used them. The sum of the resource costs of an activity form the activity costs, which are assigned to the cost objects (products, divisions, sales channels, customer groups, etc.) with the help of so-called "cost drivers". Cost drivers are measures of the resource consumption of the activities and therefore determine the level of the activity costs. These should be distributed to the cost objects.
In the case of ABC, product costs are the sum of the costs of all activities that are required to manufacture and deliver a product. The costs are therefore not charged on the basis of resource consumption, as was previously the case, but on the activity consumption of individual products. The ABC refers to all cost components that cannot be offset as direct costs (such as material costs and wages), in particular to production overheads. The area of application of the ABC is not limited to the indirect areas, but also expressly includes production. The costs are offset as shown in the figure in two stages with a total of five steps:
⦁ Identification of activities and summary of activities
⦁ Decision about showing the activity costs
⦁ Determination of the reference values on the 1st level and the activity costs
⦁ Delimitation of activity centers
⦁ Determination of the reference values of the 2nd level and allocation to cost objects
In the first stage the costs are allocated to the activities and in the second stage to the cost objects (products etc.).
The ABC takes two different perspectives: On the one hand, the cost flow from the resources to the activities to the cost objects is considered (“cost view”). On the other hand, the company process is in the foreground, ie which factors determine the execution of the activities, how the execution of the activities takes place and which results are achieved with it ("Process View"). The cost view provides information about operational resources, activities and cost objects.
The link between these elements takes place via cost drivers of the first and second level. It is assumed that operational resources are required to carry out activities that are in turn required for various cost objects (such as the creation of a product). This characterizes the flow of costs within the company. However, this view can also be reversed by assuming that the creation of a product requires activities that require resources to carry out. This flow of resources required, which runs in the opposite direction to the flow of costs, characterizes the demand of the cost objects for resources exerted by the activities.
It should be noted that ABC and process costing must not be equated, because their areas of application and methodology differ considerably. Process cost accounting was developed primarily to control overhead costs in non-production areas. On the other hand, the main focus of the ABC is on manufacturing overheads. There are only overlaps in the indirect overhead areas. While the ABC was basically designed for use throughout the company, the use of process costing is limited to cost centers in indirect areas with predominantly repetitive activities.
Because of this, the ABC can be seen as an independent alternative to traditional cost accounting systems; Process cost accounting, on the other hand, is only a supplement or partial alternative to the existing cost accounting, especially marginal cost accounting. Process cost accounting also relativizes the ABC's claim to plan and measure practically all of the company's activities and to allocate their costs to the products based on the cause.