Which versus that: identify the group.
By Adam Frick · Illustrated draftWhich reports must you restrict?
You receive an instruction to restrict access to reports containing personal data. Does the instruction cover every report on your desk, or only the reports with that information? The difference matters before you change anyone’s access. I recommend a consistent way to distinguish the selected group from an extra comment about a group already identified. Watch the scope change between the first two examples.
See the supporting references.Watch the boundary move.
Select the relevant reports.
Constructed teaching exampleThe reports that contain personal data require restricted access.
Report A: personal data ✓ · Report B: personal data ✓ · Report C: no personal data
Describe the whole identified group.
Constructed teaching exampleThe reports, which contain personal data, require restricted access.
Report A ✓ · Report B ✓ · Report C ✓
Do not use deletion as the only test.
Constructed teaching exampleThe reports that contain personal data require restricted access.
The reports require restricted access.
See the published wording.
Dual-use items are goods, software and technology which can be used for both civil and military applications.
Do not replace every “which”.
I prefer defining “that” as a repeatable teaching convention, but British English also permits defining “which”. That accepted alternative is not a mistake merely because my preferred pattern is narrower. A construction such as “the method by which” needs its preposition and cannot accept a mechanical swap. What matters in the report example is the group the instruction covers, not winning a contest between two words.
References and evidence
- UK Government, National Security and Investment Act guidance, “Military and Dual-Use” ↩
- British Council’s grammar guidance ↩
Read the evidence and its limits.
The British Council’s grammar guidance[2] allows “which” as well as “that” in defining clauses about things. My narrower recommendation gives writers one repeatable way to mark the distinction. A reader should not need to guess whether a clause selects a group or comments on an established group. Consistency can support that aim without turning a permitted alternative into an error.