A buying center brings together "all those members of an organization who become involved in the buying process for a particular product or service". Buying centers are also sometimes known as 'decision-making units' (DMUs). The concept of a buying center (as a focus of business-to-business marketing) represents an attempt to formalise understanding of purchasing decision-making in complex environments.
The key factors influencing a buying center or DMU's activities include:
- Buy class (e.g. straight rebuy, new task or modified rebuy)
- Product type (e.g. materials, components, plant and equipment and MRO (maintenance, repair and operation))
- Importance of the purchase 
When the DMU wants to purchase a certain product or service the following steps are taken inside the buying center:
- Need or problem recognition: the recognition can start for two reasons. The first reason can be to solve a specific problem of the company. The other reason can be to improve a company’s current operations/performance or to pursue new market opportunities.
- Determining product specification: The specification includes the peculiarities that the product/service that is going to be purchased has to contain.
- Supplier and product search: this process contains the search for suppliers that can meet a company’s product or service needs. First a supplier that matches with the specifications of the company has to be found. The second condition is that the supplier can satisfy the organizations financial and supply requirements.
- Evaluation of proposals and selection of suppliers: the different possible suppliers will be evaluated by the different departments of the company.
- Selection of order routine: this stadium starts after the selection of the supplier. It mainly consists of negotiating and agreeing with the supplier about certain details.
- Performance feedback and evaluation: performance and quality of the purchased goods will be evaluated.
In this process of making decisions different roles can be given to certain members of the center of the unit depending on the importance of the part of the organization.
The different roles are:
- Initiator: the initiator(s) make a request to purchase a product or service or recognizes the problem, with this action they start the decision-making process. e.g. maintenance manager
- Decider: the decider makes the actual purchase decision. Typically, they don’t have or need formal authority but have sufficient weight within the buying team to decide if a service/product will be purchased.
- Buyer: the buyer (also called: purchasing manager) selects the suppliers and manages the buying process such that the necessary products are acquired.
- Influencer: the influencer contributes to the formulation and determination of the specifications of the product or service. The influencer evaluates and recommends which potential supplier satisfies the specific needs of the organization.
- User: the user(s) are the persons that actually use the product or service. They are not always involved in the buying process, but have a critical role in the feedback and evaluation process of the performance of the good that has been purchased .
- Gatekeeper: the gatekeeper(s) control(s) the flow of information in to and out of the company and buying center/team.*
In some cases the buying center is an informal ad hoc group, but in other cases, it is a formally sanctioned group with specific mandates, criteria, and procedures.
The formation of the buying centers or decision-making unit (DMU) is considered as an important process and therefore depends on several factors like: the size of the company and skills of the personalities and staff members, the type of product/service that is needed, the type of the organization, the different buying process stages (BPS), the duration of the relationships between the buyer (the organization) and sellers or suppliers, and the technologies that are used in the production.
Buying center size
An American research done by McWilliams in 1992 found out that the mean size of these buying centers mainly consists of four people. The normal range is between three and five people. The main reason for variety in amount of people is the type of purchase that has to be done and the stage of the buying process.
Conceptual and Methodological Issues in Buying Centre Research
There are several issues concerning buying centres, which are always important and need additional research. These issues can be divided into various spheres:
Buying Centre Boundaries and Buying Centre Domain
Distinguishing the buying center from its environment, also defining and delimiting the activities of a particular buying center.
Buying Centre Structure
Understanding how organizational structure may differ from or may shape the structure of the buying center. Examining how a particular buying strategy may serve to mediate the effects of environmental uncertainty on the structure of the buying center.
Process Considerations in Buying Centre
Power and conflict issues within the buying center.
One stream of research focuses on the number of decision phases and their timing and the other emphasizes the type of decision-making model (or choice routine) utilized.
The informal interactions that emerge during the buying process.
- Robinson, P. J., C. W. Farris, and Y. Wind (1967), Industrial Buying and Creative Marketing, Boston, MA: Allyn and Bacon, quoted in Wesley J. Johnston and Thomas V. Bonoma, "The Buying Center: Structure and Interaction Patterns" in Journal of Marketing, Vol. 45, No. 3 (Summer, 1981), pp. 143-156, accessed 6 December 2015
- Jobber, David; Ellis-Chadwick, Fiona (2013). "5". Principles and Practices of Marketing (7th ed.). Maidenhead, UK: McGraw-Hill Higher Education. pp. 162–165. ISBN 9780077140007.
- Conceptual and Methodological Issues in Buying Centre Research by Bobert B. Spekman and Kjell Gronhaug