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Use must not shall to impose requirements. [S2] Besides being outdated, shall is imprecise. [S1] It can indicate either an obligation or a prediction. [S1] Dropping shall is a major step in making your writing more user-friendly. [S1] Many agencies already use the word must to convey obligations. [S1]

Checklist

1. [ ] Use must to convey obligations. [S1]
2. [ ] Do not use shall to impose requirements. [S2]
3. [ ] Remember that shall can indicate either an obligation or a prediction. [S1]
4. [ ] Nobody uses shall in common speech. [S2]
5. [ ] Dropping shall makes your writing more user-friendly. [S1]

Done when: must conveys obligations. [S1] Dropping shall makes your writing more user-friendly. [S1]

Claims

• id: C1 claim: Use must rather than shall for requirements. source: S2 evidence: "Use \"must\" not \"shall\" to impose requirements."
• id: C2 claim: Shall is imprecise as well as outdated. source: S1 evidence: "Besides being outdated, \"shall\" is imprecise."
• id: C3 claim: Shall can mean obligation or prediction. source: S1 evidence: "It can indicate either an obligation or a prediction."
• id: C4 claim: Many agencies already use must for obligations. source: S1 evidence: "Many agencies already use the word \"must\" to convey obligations."
• id: C5 claim: Nobody uses shall in common speech. source: S2 evidence: "Third, nobody uses \"shall\" in common speech."

Sources

• [S1] Use “must” to indicate requirements. GSA / PlainLanguage.gov archive. https://raw.githubusercontent.com/GSA/plainlanguage.gov/main/_pages/guidelines/conversational/use-must-to-indicate-requirements.md . License: US government work, public domain. Accessed 2026-11-05.
• [S2] Shall and must. GSA / PlainLanguage.gov archive. https://raw.githubusercontent.com/GSA/plainlanguage.gov/main/_pages/guidelines/conversational/shall-and-must.md . License: US government work, public domain. Accessed 2026-11-05.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).

@misc{iil_note_prt8jhfx,
  author = {{iinventedlight}},
  title = {{Use must for requirements instead of shall}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-05},
  url = {https://iinventedlight.com/library/notes/plain-language-must-not-shall/},
  note = {Permanent ID iil:note:prt8jhfx. License: CC-BY-4.0.},
}

Markdown

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