An issue I see come up in manuscripts as submitted as well as occasionally after editing concerns restrictive versus nonrestrictive clauses, commonly referred to as the “that versus which” issue. It can be especially confusing because usage differs in the United States versus the United Kingdom.

Let’s start with two definitions. (From The Chicago Manual of Style, 17e; edited.) The end of the quoted material is marked by the box (■).

Section 6.27: Commas with Relative Clauses—“That” versus “Which” 

A clause is said to be restrictive (or defining) if it provides information that is essential to the meaning of the sentence. Restrictive relative clauses are usually introduced by that (or who/whom/whose) and are never set off by commas from the rest of the sentence. 

The manuscript that the editors submitted to the publisher was well formatted.

I prefer to share the road with drivers who focus on the road rather than on what they happen to be reading.

A clause is said to be nonrestrictive (or nondefining or parenthetical) if it could be omitted without obscuring the identity of the noun to which it refers or otherwise changing the intended meaning of the rest of the sentence. Nonrestrictive relative clauses are usually introduced by which (or who/whom/whose) and are set off from the rest of the sentence by commas. 

The final manuscript, which was well formatted, was submitted to the publisher on time.

Ulysses, which I finished early this morning, is due back on June 16. 

I prefer to share the road with illiterate drivers, who are unlikely to read books while driving.

■

For nonrestrictive clauses, there’s a standard for usage:

The final manuscript, which was well formatted, was submitted to the publisher on time.

It’s really important to understand that in a case like this the clause (“which was well formatted”) must be preceded and followed by a comma.

The way I recommend determining whether a clause is nonrestrictive is to read the sentence without the clause. If the sentence still makes sense, it’s a nonrestrictive clause. If we omit that clause in the example given above, what remains is this:

The final manuscript was submitted to the publisher on time.

It makes perfect sense and is grammatically correct. This means that the clause we omitted is providing additional information. That makes it nonrestrictive and commas are needed.

Restrictive clauses are trickier because the conventions with US and UK authors are different.

A restrictive clause is a case where the information in the clause is essential to the sentence. Without it, the sentence would be incomplete. No commas are needed before or after restrictive clauses.

Here’s the US convention. The restrictive clause is shown in bold:

The version of the manuscript that the editors submitted to the publisher was well formatted.

Here’s the UK convention. The restrictive clause is shown in bold:

The version of the manuscript which the editors submitted to the publisher was well formatted.

Note the difference: US authors use “that” while UK authors use “which.”

Applying the same technique described above, let’s again read the sentence without the clause:

The version of the manuscript was well formatted.

The sentence is incomplete (because we haven’t defined which manuscript we’re talking about). So in this case, the clause is needed, but no commas are used:

The version of the manuscript which the editors submitted to the publisher was well formatted.

The restrictive versus nonrestrictive clause is one of the many tricky areas that are easily handled by the editorial staff at Virtus, who can provide solid advice regarding issues such as these. 

Like this post? Follow Virtus Publishing on LinkedIn!