that vs. which

Linguistic Reminder

(This reminder is available in English only.)

Problem

Canadian author and playwright Robertson Davies once confessed that he wasn't quite sure when to use that and when to use which. Many of us can empathize.

Solution

Choose the pronoun that when the clause contains essential (identifying) information. If the clause gives non-essential (additional) information, choose which.

Examples of the use of that and which
Use that	Use which
for information that is essential, or identifying: The dog that was lost has come home. [that was lost identifies the dog] The parcel that arrived today is for Sharon. [that arrived today identifies the parcel] Note: Although that is preferred, you may also use which with essential clauses: The dog which was lost… The parcel which arrived… Punctuation Tip: No commas are used with an essential clause.	for information that is non-essential, or additional: The neighbours' dog, which was lost, has come home. [The neighbours' identifies the dog; the clause which was lost is additional information] Please pick up our November order, which arrived today. [November identifies the order; the clause which arrived today is additional information] Punctuation Tip: A non-essential clause is set off with one or two commas.

References

In preparing this linguistic reminder, we consulted the following sources:

Canadian Writer's Handbook (2008)
Editing Canadian English (2000)
Gregg Reference Manual (2006)
Guide to Canadian English Usage (2007)
Pocket Fowler's Modern English Usage (2008)
Practical English Usage (2005)
"That and Which: Which Is Which?" (Frances Peck, Language Update, Vol. 34, No. 4, 2001)

Linguistic Recommendation reference number

REM-29/2011-02

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