Heuristic
Give each requirement one behavior to prove
One sentence can hide three different definitions of done.
When it fits
- A sentence contains several actions, exceptions and outcomes joined by 'and' so partial completion is hard to see.
When to avoid it
- Do not fragment a single coherent condition into tiny statements that lose necessary context; the unit is one independently meaningful behavior.
Why it matters
Split independently verifiable behaviors into separate requirement or acceptance statements. Keep shared rationale outside the statements. If two behaviors must always be verified together, explain why rather than joining them for convenience.
An example
'The service validates the file, rejects invalid rows and emails a report' becomes three checkable outcomes with their own error cases.
Check your result
Each statement can be marked pass or fail without the answer depending on another clause in the same sentence.
Keep this limit in mind
- Do not fragment a single coherent condition into tiny statements that lose necessary context; the unit is one independently meaningful behavior.
Connected ideas
Useful withWrite acceptance evidence before implementation starts
Evidence and sources
NASA's requirements checklist emphasizes clarity, one thought per requirement, completeness, explicit assumptions, consistency, traceability, feasibility and verifiability.
The checklist is for systems engineering; smaller tasks can apply the principles proportionally.
Appendix C: How to Write a Good Requirement · Requirements validation checklist
NASA recommends identifying a verification approach for requirements and keeping each requirement uniquely identifiable with a definitive source.
The appropriate verification method and documentation depth depend on risk and project scale.
Appendix D: Requirements Verification Matrix · Requirements Verification Matrix