Flexible resources are resources that generate cost in proportion to the amount used. Flexible resources are supplied as used and needed. The flexible resources are acquired from outside resources. The terms of acquisition for the flexible resource do not require the any long-term commitment for any given amount of the resource. The organization is free to buy what it needs and when it needs it. Therefore the quantity of the resource supplied equals the quantity demanded. There is no unused capacity for this category of resources.
Direct material is a flexible resource. Direct materials are materials that are directly assigned to each unit of production, cost center or work order. The direct materials are taken directly from the direct materials inventory. Direct materials are defined as the cost of the material that can be specifically identified with the product. Direct materials include items like raw materials, standard and specialized parts, and sub-assemblies required to assemble or manufacture a complete product
The cost of flexible resources is equal to the cost of resources used and thus the total cost of the resources increases as the demand for the resources increase. The cost of flexible resources is generally treated as a variable cost. For example, in a just-in-time manufacturing environment the materials are purchased when needed.
Using the units produced as an output measure, or a driver, it shows that the units produced increase, the usage and cost of direct materials would increase proportionately. Power is also a flexible resource. Some of the examples of flexible resources are materials, energy, telecommunications services, temporary hired workers on a daily basis, employees paid on a piece-work basis and overtime that is authorized.