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Requirements Analysis

About

The Requirements Analysis process results in the decomposition of end-user needs (usually identified in operational terms at the system level during implementation of the Stakeholder Requirements Definition process; see DAG CH 3–4.2.1. Stakeholder Requirements Definition Process) into clear, achievable and verifiable requirements.

image of three people looking at sticky notes on a wall and moving them around

As the system design evolves, Requirements Analysis activities support allocation and derivation of requirements down to the system elements representing the lowest level of the design. The allocated requirements form the basis of contracting language and the system performance specification. The resultant system requirements are addressed at technical reviews and audits throughout the acquisition life cycle and captured in applicable program and systems engineering (SE) technical documentation.

Scope

The Requirements Analysis process objectives includes:

  • Linking the needs of the end users to the system, system elements and enabling system elements to be designed and developed.
  • Defining a system that meets end-users' operational mission requirements within specified cost and schedule constraints.
  • Providing insight into the interactions among various functions to achieve a set of balanced requirements based on user objectives.

Process

The process of defining, deriving and refining requirements proceeds as follows:

  1. Analyze user requirements.
  2. Translate end-user needs into basic functions.
  3. Develop a quantifiable set of performance requirements by defining the functional boundaries of the system in terms of the behavior and properties to be provided.
  4. Define each function that the system is required to perform.
  5. Define implementation constraints (stakeholder requirements or solution limitations).
  6. Translate performance requirements into specific system technical design requirements and functions.

End Products

The Requirements Analysis process provides:

  • Translation of end-user needs (usually stated in operational terms) to unambiguous, verifiable and feasible system performance specification requirements.
  • Incorporation of design considerations, including statutory and regulatory constraints (see CH 3–4.3. Design Considerations).
  • Allocation of requirements from the system-level specification to the lowest-level system elements and enabling system elements.
  • Rationale for specification requirements and their decomposition/allocation.
  • A mechanism to support trade-off analyses between related requirements to provide maximized mission assurance within cost and schedule constraints.
  • A framework for accurate assessment of system performance throughout the life cycle.

Requirements Analysis encompasses the definition and refinement of the system, system elements, enabling system elements and associated functional and performance requirements. The development of the functional baseline is largely a product of the Requirements Analysis process. All requirements are placed under configuration control, tracked and managed as described in the Requirements Management process and Configuration Management process (see DAG CH 3–4.1.4. Requirements Management Process and CH 3–4.1.6. Configuration Management Process, respectively).

Writing Well-crafted Requirements

Importance

The Requirements Analysis process is an iterative activity whereby system requirements are identified, refined, analyzed and traded to remove deficiencies and minimize the impacts of potential cost drivers to establish an agreed-to set of requirements coordinated with the appropriate stakeholders. Poorly written requirements can lead to significant problems in the areas of schedule, cost or performance, and can thus increase program risk.

A well-crafted set of functional/performance requirements can then be translated into design requirements for the total system over its life cycle and can allow stakeholders to assess system performance during execution of the Verification and Validation processes (see DAG CH 3–4.2.6. Verification Process and DAG CH 3–4.2.7. Validation Process, respectively).

Attributes

Good requirements have the following attributes:

  • Necessary
  • Unique
  • Unambiguous - clear and concise
  • Complete
  • Consistent
  • Technically feasible/achievable/obtainable
  • Traceable
  • Measurable/quantifiable
  • Verifiable (e.g., Testable)
  • Able to be validated
  • Operationally effective
  • Singular

The Requirements Analysis process ensures that requirements derived from user-specified capability needs are analyzed, decomposed, and functionally detailed across the system design. Early development and definition of requirements using the attributes listed above reduces development time, enables achievement of cost and schedule objectives and increases the quality of the final system.


Resources

Key Terms

Requirement
Requirements Analysis
Requirements Creep
Requirements Manager
Requirements Scrub

Source: DAU Glossary

Statutes, Regulations, Guidance

DAU Training Courses

Products and Tasks

Product Tasks
AWQI 3-1-1: Document functional baseline
  1. Identify user needs from joint capability integration and development system (JCIDS) documents and other sources.
  2. Translate user needs into system performance specification technical requirements.
  3. Identify and incorporate design considerations into system performance specification.
  4. Document allocation of system requirements in the system requirements traceability matrix.
  5. Document the rationale for system specification requirements and their decomposition/allocation in the requirements traceability verification matrix.
  6. Determine relationships of system requirements with other system requirements, and categorize into related domains.
  7. Conduct trade-off analyses between related system requirements.
  8. Document system requirements into a system functional baseline.

Source: AWQI eWorkbook