Establish and maintain product and product component requirements, which are based on the customer requirements.

The customer functional and quality attribute requirements can be expressed in the customer’s terms and can be nontechnical descriptions. The product requirements are the expression of these requirements in technical terms that can be used for design decisions. An example of this translation is found in the first House of Quality Function Deployment, which maps customer desires into technical parameters. For instance, “solid sounding door” may be mapped to size, weight, fit, dampening, and resonant frequencies.

Product and product component requirements address the satisfaction of customer, business, and project objectives and associated attributes, such as effectiveness and affordability.

Derived requirements also address the needs of other lifecycle phases (e.g., production, operations, disposal) to the extent compatible with business objectives.

The modification of requirements due to approved requirement changes is covered by the “maintain” aspect of this specific practice; whereas, the administration of requirement changes is covered by the Requirements Management process area.

Refer to the Requirements Management process area for more information about managing requirements.

Example Work Products

1.    Derived requirements

2.    Product requirements

3.    Product component requirements

4.    Architectural requirements, which specify or constrain the relationships among product components

Subpractices

1.    Develop requirements in technical terms necessary for product and product component design.

2.    Derive requirements that result from design decisions.

Refer to the Technical Solution process area for more information about selecting product component solutions and developing the design.

Selection of a technology brings with it additional requirements. For instance, use of electronics requires additional technology specific requirements such as electromagnetic interference limits.

Architectural decisions, such as selection of architecture patterns, introduce additional derived requirements for product components. For example, the Layers Pattern will constrain dependencies between certain product components.

3.    Develop architectural requirements capturing critical quality attributes and quality attribute measures necessary for establishing the product architecture and design.

4.    Establish and maintain relationships between requirements for consideration during change management and requirements allocation.

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

Relationships between requirements can aid in evaluating the impact of changes.