IMPORTANT: This topic is about which vs. that. However, all of the following examples contain discussions of multiple subjects—not just which vs. that. Therefore, in addition to which vs. that, you are going to learn a lot of different things about good writing and rewriting.

Example 1

REWRITE THIS SENTENCE

PROBLEM

Two problems:

The word which is for a non-restrictive clause. The word that is for a restrictive clause. The example sentence has a restrictive clause. We need to change which to that.
The sentence would sound better if we change the passive voice to active voice.

As a usage preference, I prefer to use the verb form to show rather than to display. The language is simpler and it says the same thing.

DISCUSSION

Which vs. That

The sentence has two clauses:

Main clause—There are some client configuration options
Restrictive clause—which control how the user data is displayed during account creation or profile updates

If you remove the restrictive clause—which control how the user data is displayed during account creation or profile updates—do you change the meaning of the sentence? Compare:

There are some client configuration options which control how the user data is displayed during account creation or profile updates
There are some client configuration options

The two sentences are much different. Don’t you agree? The second sentence is just a bald statement that there are some options. What does that tell you that you did not know already? The first sentence actually has some useful and interesting content.

A restrictive clause points to a part of a sentence that you cannot remove from the sentence because it restricts some other part of the sentence. Specifically, you cannot take it out of the sentence without changing the meaning of the sentence.

So, what is a good example of a non-restrictive clause? Which of the following sentences sounds right to you?

My sister lives in Cambria that is five miles from the Hearst Castle.

Or this:

My sister lives in Cambria, which is five miles from the Hearst Castle.

Active Voice

Who or what is the actor that controls the display of user data during account creation of profile updates? You could say the system does that. You could also say the user interface does that. Either one would work as the subject. We’ll show both in the revised version.

REVISION

Before

There are some client configuration options which control how the user data is displayed during account creation or profile updates.

After

There are some client configuration options that control how the system shows user data during account creation or profile updates.

There are some client configuration options that control how the user interface shows user data during account creation or profile updates.

Example 2

REWRITE THIS SENTENCE

PROBLEM

In technical documentation, the word which is frequently used incorrectly in place of the word that. Our problem sentence is a good example of this incorrect usage.

Copy editors spend a lot of time replacing which with that. This activity is called which hunting.

DISCUSSION

Let’s take a look at the sentence. The sentence has two clauses:

Main clause—An affiliate is a FakeCorp-affiliated organization
Restrictive clause—which can sell products through the FakeCorp network

If you remove the restrictive clause—which can sell products through the FakeCorp network—do you change the meaning of the sentence? Compare:

An affiliate is a FakeCorp-affiliated organization which can sell products through the FakeCorp network.
An affiliate is a FakeCorp-affiliated organization.

Do you see the difference?

When is it OK to use the word which in a sentence? The following is an example of how we can make the restrictive clause into a non-restrictive clause:

A FakeCorp-affiliated organization, which can sell products through the FakeCorp network, must comply with the terms and conditions of the contract.

See how the meaning of the main clause—A FakeCorp-affiliated organization must comply with the terms and conditions of the contract—remains intact when you remove the non-restrictive clause—which can sell products through the FakeCorp network.

REVISION

Before

An affiliate is a FakeCorp-affiliated organization which can sell products through the FakeCorp network.

After

An affiliate is a FakeCorp-affiliated organization that can sell products through the FakeCorp network.

Example 3

REWRITE THESE SENTENCES

PROBLEM

The authors use the word which incorrectly in place of the word that.

DISCUSSION

Sentence 1

Let’s take a look at the sentence. The sentence has two clauses:

Main clause—The fastest way is to port from a project
Restrictive clause—which uses the validation filter already

If you remove the restrictive clause—which uses the validation filter already—do you change the meaning of the sentence? Compare:

The fastest way is to port from a project which uses the validation filter already.
The fastest way is to port from a project.

As you can see, the two sentences are completely different in meaning. The set of words which uses the validation filter already is a restrictive clause. A restrictive clause points to a part of a sentence that you cannot remove from the sentence because it restricts some other part of the sentence.

Sentences 2 and 3

Apply the same logic to the second and third sentences. Take the restrictive clause out and see what you have left.

Nonrestrictive vs. Restrictive Clauses Explained

See the Remarks section at the end of this post for a detailed explanation of the difference between nonrestrictive and restrictive clauses.

Rule

Whenever you have restrictive clauses, use the word that or some other word or phrase—without punctuation—instead of which.

REVISIONS

Before

The fastest way is to port from a project which uses the validation filter already.

This is the descriptive name which identifies attributes for a specific database attributes.

Others may return a token object which represents an access token.

After

The fastest way is to port from a project that uses the validation filter already.

This is the descriptive name that identifies attributes for a specific database attributes.

Others may return a token object that represents an access token.

REMARKS

Cal State Long Beach Department of English has a website called the Writer’s Resource Lab. The website has a good explanation of the difference between nonrestrictive and restrictive clauses. Here is the full quotation:

Nonrestrictive vs. Restrictive

Nonrestrictive (also called “nonessential”) elements of a sentence are not necessary to the meaning of the sentence. If you were to remove the nonrestrictive word, phrase or clause, the sentence would still have the same meaning. Nonrestrictive words, phrases and clauses serve to add extra detail to a sentence without changing its meaning, and are marked by commas.

You may have guessed, then, that restrictive (also called “essential”) elements of a sentence are necessary to the meaning of the sentence; as the name suggests, they restrict the sentence to a particular meaning. If you were to remove the restrictive word, phrase or clause, the sentence would have a different meaning. Restrictive words, phrases and clauses do not require commas.

The following examples show the nonrestrictive word, phrase or clause is in italics:

Francesca’s husband, Nathan, accompanied her to the poetry reading.

Here, Nathan is nonrestrictive because, while it offers an extra detail about Francesca’s husband, it is not necessary to the meaning of the sentence. If you were to remove Nathan, the sentence would still be about Francesca’s husband. Because Francesca can only have one husband, it is not essential to know his name for the sentence to make sense.

Reusable shopping bags, relatively unknown two years ago, have exploded in popularity since the “green” movement became fashionable.

In this sentence, relatively unknown two years ago is a nonrestrictive phrase. While it adds a detail about reusable shopping bags, if it were removed it would still be clear that reusable bags have become more popular with the rise of the “green” movement. The sentence would have the same meaning if the phrase were removed, so the phrase is nonrestrictive.

The beach picnic was a success on that beautiful day, which was the first sunny day of the summer.

In this case, which was the first sunny day of the summer is a nonrestrictive clause because, while it adds detail about the beautiful day, it does not affect the meaning of the sentence. The sentence would still have the same meaning—that the beach picnic was a success—without that clause.

Consider the following examples where the restrictive word, phrase or clause is in italics:

My cousin Allison just graduated from high school.

Allison is a restrictive word because it makes the sentence about that one particular cousin; it indicates that the author has several cousins and/or several cousins who just graduated from high school. If Allison were removed, the sentence would imply that the writer has only one cousin and that cousin just graduated from high school. Because removing the word Allison would change the meaning of the sentence, it is restrictive.

The dog with the white spot on his nose belongs to my neighbor.

Here, with the white spot on his nose is a restrictive phrase because it makes the sentence about that one particular dog. Without the phrase, the sentence would no longer be referring to that specific dog, so the meaning of the sentence would change; therefore; with the white spot is a restrictive phrase.

The man who delivers the mail is always very friendly.

In this case, who delivers the mail is a restrictive clause that specifies one particular man. If the clause were removed, the sentence would be too general and it would be unclear who, exactly, is very friendly. Because removing the clause would alter the meaning of the sentence, the clause is restrictive.

Example 4

REWRITE THIS SENTENCE

PROBLEM

The main problem with this sentence is its use of the word which instead of that.

The sentence has some readability issues because seven of the 24 words have three or more syllables. Take a look at the vocabulary and see if you can find some short but accurate replacement words.

Finally, you could rewrite the sentence as two shorter sentences and, thus, improve the readability even more.

DISCUSSION

Which vs. That

After all these years, I still have a problem with the distinction between a restrictive clause and a nonrestrictive clause. It always gives me pause. Usually, I make the right decision, but not always.

If you find it confusing, you are not alone!

Usage

These words have three or more syllables:

subarea
policies
encourage
integration
development
natural
techniques

Can you identify more readable—but accurate—synonyms?

Simple Sentences

The draft subarea plan includes two things:

Policies that encourage integration of development with natural systems
The use of LID techniques to manage storm water

See the Revision section for a two-sentence suggestion.

NOTE: By converting the example sentence to two sentences, you reduce the fog index by five years of education.

REVISION

Before

The draft subarea plan includes policies which encourage integration of development with natural systems and the use of LID techniques to manage storm water.

After

The draft subarea plan includes policies that encourage integration of development with natural systems and the use of LID techniques to manage storm water.

The draft subarea plan includes policies that encourage integration of development with natural systems. Also, it describes the use of LID techniques to manage storm water.