Final answer:
The purchasing system in which department heads or designated employees make most purchases is called decentralized procurement, allowing for department-specific flexibility and response to needs with necessary coordination for organizational efficiency.
Step-by-step explanation:
The term that refers to the purchasing system wherein all or most purchases are made by department heads or designated employees within the department is known as a decentralized procurement system. In this system, the authority to make purchase decisions is distributed among various departments within an organization, rather than being centralized in a single purchasing department. This can be seen, for example, in how the government might empower the heads of different departments, such as the Department of the Interior or the Department of Transportation, to make their own procurement decisions for their specific needs. Similarly, in corporate scenarios, after mergers or acquisitions, each unit may retain some level of autonomy in procurement to cater to their unique requirements until a unified system is established. A decentralized system might allow for greater flexibility and quicker response times to departmental needs, but could also require effective coordination to ensure organizational efficiency and cost-effectiveness.