هزینه یابی بر مبنای فعالیت و مدل سازی برای طراحی محصول هزینه-آگاه : یک مطالعه موردی در یک شرکت تولیدی

The most effective way to control costs is to design them out of the products. However, cost data is rarely available for product designers in a usable form. The aim of this study was to investigate the possibilities of activity-based costing and the modeling of design, purchasing and manufacturing processes in providing useful cost information for product designers. The hypothesis was that activity-based costing and process modeling might provide an effective tool for the evaluation of different design options. The study was conducted in a large Finnish manufacturing company. First, the most costly items of one product's sub-assembly were studied in order to identify the activities needed to produce the items and to calculate their activity-based costs. Second, the processes, in other words the activity chains, were modeled with graphic flowcharts from product design, purchasing, and manufacturing departments. Finally, the applicability of activity-based cost information and process models to product designing practices was tested. The results of the study suggested that activity-based costing and process modeling provide a good starting point in heading toward more cost-conscious design. This way the designers learn the relationships between the activities performed in the organization and their associated costs. The development of a parametric cost estimation model based on activity-based costing and process modeling provides a challenge for future research.

1.1. Product design and cost accounting The important role of product development in cost management is undeniable. However, the need for cost information in product development has not been sufficiently met. Problems include both the content as well as the form of information. Uusi-Rauva and Paranko [1] examined the present state of cost accounting from a designer's point of view in four Finnish manufacturing companies. During the study both accounting professionals (information producers) and managers of designers (users of information) were interviewed. As a result 11 improvement opportunities were presented, of which two are presented here. First, cost information should be better combined with product structure and business process activities. Second, designers need reliable information on a product's total costs. It is common for designers to get information only on a product's direct costs. However, the decisions made on product design also affect indirect costs [2]. Cost accounting should help product development to design products that carry the lowest possible total costs while also taking into consideration other important design criteria. Cooper and Turney [3] have argued that activity-based costing provides cost information on each of the company's production processes so that the costs of different designs can be compared. According to them, activity-based costing (ABC) puts product costs “on the backs” of the engineers [3]. Consequently, companies develop ABC systems to provide more relevant economic information for product designers [4]. 1.2. Definitions A number of writers [5], [6], [7], [8] and [9], have provided definitions for a business process. According to Laakso a business process is a structured, measured set of activities and flows that use necessary resources of the organization to provide a specified output for a particular customer [10]. Smart et al. [11] offer a general process classification framework. The framework is helpful in specifying the business processes as well as in determining the process boundaries. In this classification, the main process classes are the operating, support, and managing processes. The operating processes are defined as the cross-functional and value-adding chains having a direct customer interface. The four main operating processes are product development, sales and marketing, order fulfillment, and customer service. Furthermore, parts of the main operating processes can be divided into sub-processes. For example, a production process can be seen as a part of the order fulfillment process. In addition to production, the order fulfillment process includes several other activities, such as customer inquiry, proposal, contract, assembly, delivery, installation and invoicing [10]. The objective of process modeling is to help companies to improve their business process understanding. A qualitative model that provides a graphical interpretation of the process captures the structure of a business process. The objective of qualitative process modeling is to visualize the process and to achieve a commonly agreed view of the process structure. Graphical process presentation facilitates communication between people and helps in developing a common conceptual model of what goes on in the studied process [10]. The graphical process models (Fig. 1) are formatted into horizontal bands to illustrate where an activity is performed and by whom. This way the involvement of various constituents of the overall process can be isolated. The process goes simultaneously from left to right and from the top down. The activities are presented with a rectangle and the branches of the process are presented with a diamond. A shadow under a rectangle indicates that an activity consists of several sub-processes. In this way the process model becomes a hierarchical entity. A quantitative analysis of quality, cost or time may be done after the process structure is visualized. The quantitative process modeling is a vital part of the in-depth process understanding. It identifies problem areas and helps to make improvement decisions based on more solid information [10]. In fact, quantitative process modeling may in our case be seen as equivalent to activity-based costing. This results from the fact that the activities of an ABC model and the process steps of a qualitative process model may be defined as identical. In summary, qualitative process modeling is the visual presentation of the process, while quantitative process modeling/ABC is the analysis of quality, cost or time of that process. It should be noticed that qualitative process modeling is not a precondition for activity-based costing. However, if this is done simultaneously with activity-based costing, important information about the procedures of the organization can be obtained quite easily. 1.3. Aim of the study The aim of this study was to investigate the possibilities of activity-based costing and process modeling in providing useful cost information for product designers. The hypothesis was that activity-based costing and process modeling might provide an effective tool for the evaluation of different design options (Fig. 2).The focus of the study is on cost accounting. The purpose was to examine the changing role of cost accounting in providing useful information for decision making by product designers. Though many of the current trends in product designing practices, such as concurrent engineering and design for manufacturing and assembly (DFMA), emphasize the role of costs, these methods are not studied here. Rather than searching directly for the improvement of product designing practices, the purpose was to investigate the usefulness of activity-based cost information and information about the company's processes for product designers. The customer of this study is product design. As majority of the total product costs incurs from decisions made in product design, product designers should be seen as the key customers of cost information. This is why the usefulness of activity-based cost calculations and process models was tested on product designers. However, even though the causes for most of the product costs can be traced back to the decisions made in product design, the costs mainly emerge in other parts of the organization. Consequently, in order to receive as much information about the product's total costs as possible, activity-based costing and process modeling were carried out in addition to product design also in the purchasing and manufacturing functions of the company.

The results of this study lend support to the results of Uusi-Rauva and Paranko [2] regarding the need in product development for cost information. The differences which emerged between these two studies concerning needs result mainly from the different interviewee groups: the previous study concentrated on the needs of managers of designers (and accounting professionals), while in this study the focus was on the needs of product designers themselves. Consequently, the needs found in this study accentuated the daily work of the designer, that is, for example, cost information by product structure, by activities and also by product parameters. On the basis of this study, it can be argued that process modeling and activity-based costing can provide useful cost information for product designers. This derives basically from the following facts. First, the cost information is presented by product structure, which is the form in which designers normally receive other important information in their daily work. Second, the process models and cost calculations reveal the effects of different design options on the whole order-to-delivery process, i.e. the total product costs. The calculations and process models created so far, however, are too complicated and too slow for daily use. The categorization of activities into larger groups and the attachment of cost information to the graphic process models provide a basis for solving this problem. Furthermore, on the basis of this information it is possible to estimate only the costs of a particular sub-assembly. Thus, feature-based costing, parametric cost estimation, etc., provide a challenge for future research. The critical role of product design in cost management is being recognized. Product design should be considered as one of the clients for a company's cost accounting; perhaps as one of the most important clients of this function. This demands a new perspective toward cost information: the content and form should vary according to who is the target of the information. Activity-based costing and process modeling provide one possible solution for providing product designers with the kind of cost information they desire and need.