The purpose of Requirements Development is to produce and analyze customer, product, and product-component requirements.
This process area describes three types of requirements:
customer requirements, product requirements, and product-component requirements. Taken together, these requirements address the needs of relevant stakeholders, including those pertinent to various product lifecycle phases (e.g., acceptance testing criteria) and product attributes (e.g., safety, reliability, maintainability). Requirements also address constraints caused by the selection of design solutions (e.g., integration of commercial off-the-shelf products).
Requirements are the basis for design. The development of requirements includes the following activities:
· Elicitation, analysis, validation, and communication of customer needs, expectations, and constraints to obtain customer requirements that constitute an understanding of what will satisfy stakeholders
· Collection and coordination of stakeholder needs
· Development of the life-cycle requirements of the product
· Establishment of the customer requirements
· Establishment of initial product and product-component requirements consistent with customer requirements
This process area addresses all customer requirements rather than only product-level requirements because the customer may also provide specific design requirements.
Customer requirements are further refined into product and product component requirements. In addition to customer requirements, product and product-component requirements are derived from the selected
design solutions.
Requirements are identified and refined throughout the phases of the product life cycle. Design decisions, subsequent corrective actions, and feedback during each phase of the product’s life cycle are analyzed for
impact on derived and allocated requirements.
The Requirements Development process area includes three specific goals. The Develop Customer Requirements specific goal addresses defining a set of customer requirements to use in the development of
product requirements. The Develop Product Requirements specific goal addresses defining a set of product or product-component requirements to use in the design of products and product components. The Analyze
and Validate Requirements specific goal addresses the necessary analysis of customer, product, and product-component requirements to define, derive, and understand the requirements. The specific practices
of the third specific goal are intended to assist the specific practices in the first two specific goals. The processes associated with the Requirements Development process area and those associated with
the Technical Solution process area may interact recursively with one another.
Analyses are used to understand, define, and select the requirements at all levels from competing alternatives. These analyses include the following:
· Analysis of needs and requirements for each product life-cycle phase, including needs of relevant stakeholders, the operational environment, and factors that reflect overall customer and end-user
expectations and satisfaction, such as safety, security, and affordability
· Development of an operational concept
· Definition of the required functionality
The definition of functionality, also referred to as "functional analysis," is not the same as structured analysis in software development and does not presume a functionally oriented software design. In object-oriented
software design, it relates to defining the services. The definition of functions, their logical groupings, and their association with requirements is referred to as a "functional architecture."
Analyses occur recursively at successively more detailed layers of a product’s architecture until sufficient detail is available to enable detailed design, acquisition, and testing of the product to proceed. As a
result of the analysis of requirements and the operational concept (including functionality, support, maintenance, and disposal), the manufacturing or production concept produces more derived
requirements, including consideration of the following:
· Constraints of various types
· Technological limitations
· Cost and cost drivers
· Time constraints and schedule drivers
· Risks
· Consideration of issues implied but not explicitly stated by the customer or end user
· Factors introduced by the developer’s unique business considerations, regulations, and laws
A hierarchy of logical entities (functions and subfunctions, object classes and subclasses) is established through iteration with the evolving operational concept. Requirements are refined, derived, and
allocated to these logical entities. Requirements and logical entities are allocated to products, product components, people, associated processes, or services.
Involvement of relevant stakeholders in both requirements development and analysis gives them visibility into the evolution of requirements.
This activity continually assures them that the requirements are being properly defined.
Specific and Generic Goals
SG 1 Develop Customer Requirements
Stakeholder needs, expectations, constraints, and interfaces are collected and translated into customer requirements.
SG 2 Develop Product Requirements
Customer requirements are refined and elaborated to develop product and product-component requirements.
SG 3 Analyze and Validate Requirements
The requirements are analyzed and validated, and a definition of required functionality is developed.
GG 3 Institutionalize a Defined Process
The process is institutionalized as a defined process.
Practice-to-Goal Relationship Table
SG 1 Develop Customer Requirements
SP 1.1 Elicit Needs
SP 1.2 Develop the Customer Requirements
SG 2 Develop Product Requirements
SP 2.1 Establish Product and Product-Component Requirements
SP 2.2 Allocate Product-Component Requirements
SP 2.3 Identify Interface Requirements
SG 3 Analyze and Validate Requirements
SP 3.1 Establish Operational Concepts and Scenarios
SP 3.2 Establish a Definition of Required Functionality
SP 3.3 Analyze Requirements
SP 3.4 Analyze Requirements to Achieve Balance
SP 3.5 Validate Requirements with Comprehensive Methods
GG 3 Institutionalize a Defined Process
GP 2.1 (CO 1) Establish an Organizational Policy
GP 3.1 (AB 1) Establish a Defined Process
GP 2.2 (AB 2) Plan the Process
GP 2.3 (AB 3) Provide Resources
GP 2.4 (AB 4) Assign Responsibility
GP 2.5 (AB 5) Train People
GP 2.6 (DI 1) Manage Configurations
GP 2.7 (DI 2) Identify and Involve Relevant Stakeholders
GP 2.8 (DI 3) Monitor and Control the Process
GP 3.2 (DI 4) Collect Improvement Information
GP 2.9 (VE 1) Objectively Evaluate Adherence
GP 2.10 (VE 2) Review Status with Higher Level Management
