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Requirement/Functional Specifications

Overview​

In project management, the requirement specification and the functional specification are two key documents that define what a system should do and how it will be implemented.

  • The requirement specification is written by the client and describes what is needed
  • The functional specification is written by the contractor and describes how the requirements will be fulfilled

Requirement Specification​

Contains the requirements of a client to a contractor and a rough idea of the desired system.

  • Description of the project goals
  • Description of the current situation
  • Safety-related requirements
  • Functional requirements (What should the system do?)
  • Non-functional requirements (e.g. performance, security, availability, usability)
  • Time frame
  • Budget

Functional Specification​

Derived from the requirement specification. It is the contractor's response describing how the requirements will be implemented.

  • Technical concept (architecture, technologies)
    • Detailed description of the system components
    • Interface definitions
    • Data models
  • Test criteria and acceptance conditions
  • Project schedule and milestones
  • Cost estimation