Parallel Structure

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Parallel structure (also called parallelism) is when two or more items (for example, nouns or clauses) are balanced within a sentence or between sentences; that is, they are treated equally grammatically and logically. Parallel structure helps ensure your reader correctly interprets your ideas because if you don’t show how two or more items clearly connect, your reader could get confused. For example, the first sentence below illustrates a lack of parallelism with one list item, “racial,” being an adjective and the rest nouns. The second sentence is revised to be grammatically parallel (all nouns):

Example: Not only do racial, gender, class, and sexuality affect a student’s academic success, but their sense of belonging also plays a big role.
Revision: Not only do race, gender, class, and sexuality affect a student’s academic success, but their sense of belonging also plays a big role.

This parallelism signals to the reader that each of these nouns equally affects a student’s academic success. Your sentences should be grammatically parallel, as well as logically parallel, meaning your ideas must be logically ordered.

Click on each topic below to learn more about forming grammatically and logically parallel sentences.

Grammatical Parallel Structure

Parallel structure is required when you write a list of two or more items joined with a coordinating conjunction. Those items can be any part of speech, including phrases or clauses, as long as each item has the same grammatical form and fits grammatically and logically in the sentence. Check the Commas and Semicolons chapter to see how to punctuate lists.

Example (adjective phrases): Many students are afraid of the future, worried about family troubles, or tired of adults giving up on them.
Example (nouns): I know that if I’m not feeling my best about something, there are always people to talk to whether professors, peer counselors, or roommates.
Example (gerund phrases): As human beings, we all tend to trust reliable sources for our important decisions, such as buying a house, going to college, or choosing a job.
Example (adjectives): This is ridiculous and pathetic.
Example (verb phrases): I sat at a table, took out my homework, and placed it on my right side. Then I turned to face the board, opened my notebook, and started to write notes.
Example (adverbs): If an educator has knowledge of dealing with conflicts, then they will know how to solve problems effectively and justly.

Similarly, in a list with a correlative conjunction (phrases like either…or, neither…nor, or both…and), parallel structure is required.

Example (“either…or” with gerund phrases): The idea of either staying in your hometown or leaving it for college can sometimes seem uncomfortable.
Example (“neither…nor” with adjectives): My culture is neither the same as Salvadorian nor Guatemalan.
Example (“both…and” with prepositional phrases): Support from rock climbing friends is crucial, both on the rock and in daily life.

Sometimes you can reduce grammatically parallel forms, especially phrases or clauses. Often the first part of the phrase or clause can modify the elements that follow it. Below is an example with verb phrases. The first sentence shows two full verb phrases and the second shows a reduced form, with the “will be” modifying the second verb.

Example (unreduced): If this is done at every level such as middle school, high school, and college and to every student, there will be a higher chance that people will be going to college and will be getting a degree.
Example (reduced): If this is done at every level such as middle school, high school, and college and to every student, there will be a higher chance that people will be going to college and getting a degree.

Here is an example with parallel clauses:

Example (unreduced): He valued education, and he questioned the United States’ education system.
Example (reduced): He valued education and questioned the United States’ education system. (Note: The comma is no longer necessary in the reduced form because the second subject was deleted. See the Commas and Semicolons chapter for more information.)

Logical Parallel Structure

In parallel structure, logic is important to guide your reader through your writing and to ensure cohesion, or connections, between your ideas. In the example below, the items in the list are all the same form (nouns), but are not logically linked; “cross country” and “track and field” are sports but “class” is not.

Example of a grammatical but illogical parallel sentence: The sports that I enjoyed the most in high school were cross country, track and field, and class.

Here’s how we can revise that sentence to make it more logically parallel and to make each of the nouns logically linked, that is, make them all sports.

Revision: The sports that I enjoyed the most in high school were cross country, track and field, and badminton.

Parallel structure is also useful when you need to list things in order of importance, in order of size, or in some other way that’s important to convey your message. Here are two more examples of grammatically and logically parallel sentences:

Example: If a climber falls from the rock, another person needs to crouch, catch the one falling, and push the climber onto the mat to assure her/his/their safety. (This structure demonstrates step-by-step instructions.)
Example: The journal report focuses on analyzing many aspects of the magazine — background, visual layout and context—in order to better understand the writing and layout techniques of a professional publication. (This structure tells the reader in what order these topics will occur in the report.)