Atomic Concise Testable


I want to write clear, understandable requirement statements.


Write requirement statements which can be understood on their own (atomic), only describe one thing (concise), and are written in a clear, understandable style:

  1. Aim to write a structured series of short statements; the use of more than three sentences may indicate the statement is too long and should be sub-divided.Think of this as the equivalent idea of ensuring code methods are maximum a screen page long, to ensure readability and keeping a check on tendency to write overlong / complex functions which should be refactored into multiple, simpler methods.
  2. Avoid “chatty” styles, such as the use of personal pronouns “I”, “we”.
  3. Start each requirement statement with “The system shall…”, or “The screen must …”. This helps to ensure the author writes in a clear third-party style, focusing on what “the system” must do.
  4. The written statement should point to how the requirement could be observed and tested in the system; this helps to focus on the underlying requirement not on alternative designs.



It is natural to write blocks of text in a prose style, using paragraphs and connected sentences. It may appear at first to make the requirements more readable. However, this style is not optimal for the specific case of requirement statements, which should be considered an engineering artifact. The aim of requirements to be provide clear, concise and atomic information to the system's designers, testers and sponsors as to the precise nature and function of the desired behaviour of the system.

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