Customer requirements are refined and elaborated to develop product and product component requirements.

Customer requirements are analyzed in conjunction with the development of the operational concept to derive more detailed and precise sets of requirements called “product and product component requirements.” Product and product component requirements address the needs associated with each product lifecycle phase. Derived requirements arise from constraints; consideration of issues implied but not explicitly stated in the customer requirements baseline; factors introduced by the selected architecture, product lifecycle, and design; and the developer’s unique business considerations. The requirements are reexamined with each successive, lower level set of requirements and architecture, and the preferred product concept is refined.

The requirements are allocated to product functions and product components including objects, people, and processes. In the case of iterative or incremental development, the requirements are also allocated to iterations or increments based on customer priorities, technology issues, and project objectives. The traceability of requirements to functions, objects, tests, issues, or other entities is documented. The allocated requirements and functions (or other logical entities) are the basis for the synthesis of the technical solution; however, as the architecture is defined or emerges, it serves as the ultimate basis for directing the allocation of requirements to the solution. As internal components are developed, additional interfaces are defined and interface requirements are established.

Refer to the Requirements Management process area for more information about maintaining bidirectional traceability of requirements.