Writing Requirements

Characteristics of Requirement Statements

  • Necessary

  • Appropriate

  • Umambiguous

  • Complete

  • Singular

    • Cannot be combination

  • Feasible

  • Verifiable

  • Correct

  • Conforming

    Standards of organisation

Characteristics of Requirement Set

  • Complete

  • Consistent

  • Feasible

  • Comperehensible

  • Able to be validated

INCOSE

40 rules for writing good textual requirements

Guidelines for Writing Requirements

Writing well-formed requirements can be achieved by using the following guidelines:

  • Use a style guide (R41, R43, R44).

  • Use a standard template for a single sentence (R3, R19).

  • Use a glossary to define terms (R4, R39, R40).

  • Use correct English expression (R13, R14, R15).

  • Use a subject appropriate to the level (R33).

  • Use explicit lists (R24, R29, R30).

  • Use the active rather than the passive voice (R2).

  • Use the definite article (R1).

  • Use the same term to mean the same thing (R38)

  • Avoid vague words (R7, R34).

  • Avoid superfluous words (R11, R22, R23).

  • Avoid unbounded statements (R10, R27).

  • Avoid escape clauses (R9).

  • Avoid the use of conjunctions (R18, R20).

  • Use of logical conjunctions (R18, R20).

  • Avoid unecessary precision (R28).

  • Be precise when necessary

  • Use units, ranges and