What is Parallel Structure?

It’s simply the practice of using the same structures or forms multiple times: making sure the parts are parallel to each other. Parallel structure can be applied to a single sentence, a paragraph, or even multiple paragraphs. Compare the two following sentences:

Was the second sentence easier to comprehend than the first? The second sentence uses parallelism—all three verbs are gerunds, whereas in the first sentence, two are gerunds and one is an infinitive. While the first sentence is technically correct, it’s easy to trip up over the mismatching items. The application of parallelism improves writing style and readability and makes sentences easier to process.

Compare the following examples:

Once again, the examples above combine gerunds and infinitives. To make them parallel, the sentences should be rewritten with just gerunds or just infinitives. Note that the first nonparallel example, while inelegantly worded, is grammatically correct: “cooking,” “jogging,” and “to read” are all grammatically valid conclusions to “She likes.”

The nonparallel example above is not grammatically correct: “down the alley sprinted” is not a grammatically valid conclusion to “The dog.” The second example, which does not attempt to employ parallelism in its conclusion, is grammatically valid; “down the alley he sprinted” is an entirely separate clause.

Parallelism can also apply to names. If you’re writing a research paper that includes references to several different authors, you should be consistent in your references. For example, if you talk about Jane Goodall and Henry Harlow, you should say “Goodall and Harlow,” not “Jane and Harlow” or “Goodall and Henry.” This is something that would carry on throughout your entire paper: you should use the same mode of address for every person you mention.

You can also apply parallelism across a passage:

• Manuel painted eight paintings in the last week. Jennifer sculpted five statues in the last month. Zama wrote fifteen songs in the last two months.

Each of the sentences in the preceding paragraph has the same structure: Name + -ed verb + number of things + in the past time period. When using parallelism across multiple sentences, be sure that you’re using it well. If you aren’t careful, you can stray into being repetitive. Unfortunately, really the only way to test this is by re-reading the passage and seeing if it “feels right.” While this test doesn’t have any rules to it, it can often help.

Rhetoric and Parallelism

Parallelism can also involve repeated words or repeated phrases. These uses are part of “rhetoric” (a field that focuses on persuading readers) Here are a few examples of repetition:

When used this way, parallelism makes your writing or speaking much stronger. These repeated phrases seem to bind the work together and make it more powerful—and more inspiring. This use of parallelism can be especially useful in writing conclusions of academic papers or in persuasive writing.

Grammatical Parallelism

Parallel structure means using the same pattern of words to show that two or more ideas have the same level of importance. Parallelism should occur on both a structural and organizational level and on a sentence level.

At a sentence level, parallel structure can happen at the word, phrase, or clause level. Joining two parallel items without the same grammatical structure can be very confusing to a reader. The usual way to join parallel structures is with the use of coordinating conjunctions, such as “and” or “or.”

Parallelism also creates a sense of rhythm and balance within a sentence. As readers, we often correct faulty parallelism—a lack of parallel structure—intuitively because an unbalanced sentence sounds awkward and poorly constructed. Sometimes, however, faulty parallelism can really make the meaning unclear. Read the following sentences aloud:

All of these sentences contain faulty parallelism. Although they are factually correct, the construction is clunky and confusing. In the first example, three different verb forms are used. In the second and third examples, the writer begins each sentence by using a noun (coordination, jeans), but ends with a phrase (to have good eyesight, wearing a suit). Now read the same three sentences that have correct parallelism.

When these sentences are written using a parallel structure, they sound more aesthetically pleasing because they are balanced. Repetition of grammatical construction also minimizes the amount of work the reader has to do to decode the sentence. This enables the reader to focus on the main idea in the sentence and not on how the sentence is put together.

Creating Parallelism

Use Coordinating Conjunctions

When you connect two clauses using a coordinating conjunction (for, and, nor, but, or, yet, so), make sure that the same grammatical structure is used on each side of the conjunction. Take a look at the following example:

The first sentence uses two different verb forms (to listen, talking). In the second sentence, the grammatical construction on each side of the coordinating conjunction (and) is the same, creating a parallel sentence.

The same technique should be used for joining items or lists in a series:

The first sentence contains two items that use the same verb construction (reduce, cut) and a third item that uses a different verb form (lowering). The second sentence uses the same verb construction in all three items, creating a parallel structure.

Use Than or As

When you are making a comparison, the two items being compared should have a parallel structure. Comparing two items without using parallel structure can lead to confusion about what is being compared. Comparisons frequently use the words than or as, and the items on each side of these comparison words should be parallel. Take a look at the following example:

In the first sentence, the elements before the comparison word (than) are not equal to the elements after the comparison word. It appears that the writer is comparing an action (swimming) with a noun (a pool). In the second sentence, the writer uses the same grammatical construction to create a parallel structure. This clarifies that an action is being compared with another action.

To correct some instances of faulty parallelism, it may be necessary to add or delete words in a sentence.

In this example, it is necessary to add the verb phrase going for to the sentence in order to clarify that the act of walking is being compared to the act of running.

Use Correlative Conjunctions

A correlative conjunction is a paired conjunction that connects two equal parts of a sentence and shows the relationship between them. Common correlative conjunctions include the following:

Correlative conjunctions should follow the same grammatical structure to create a parallel sentence. Take a look at the following example:

When using a correlative conjunction, the words, phrases, or clauses following each part should be parallel. In the first sentence, the construction of the second part of the sentence does not match the construction of the first part. In the second sentence, omitting needless words and matching verb constructions create a parallel structure. Sometimes, rearranging a sentence corrects faulty parallelism.

To see examples of parallelism in use, read some of the great historical speeches by rhetoricians, such as Abraham Lincoln and Martin Luther King Jr. Notice how they use parallel structures (and repetition) to emphasize important points and to create a smooth, easily understandable speech. Here is a link to text, audio, video, and the music of Rev. Martin Luther King, Jr.’s speech, “I Have a Dream”: http://www.mlkonline.net/dream.html.

Proofreading Strategies for Parallelism

• Skim your paper, pausing at the words “and,” “or,” and “but.” Check on each side of these words to see whether the items joined are parallel. If not, make them parallel.
• If you have several items in a list, put them in a column to see if they are parallel.

Listen to the sound of the items in a list or the items being compared. Do you hear the same kinds of sounds? For example, is there a series of “-ing” words beginning each item? Or do you hear a repeated rhythm? If something is breaking that rhythm or repetition of sound, check to see if it needs to be made parallel.