What exactly 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:
- Yara loves running, to swim, and biking.
- Yara loves running, swimming, and biking.
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 it makes sentences easier to process.
Compare the following examples:
- Lacking parallelism: “She likes cooking, jogging, and to read.”
- Parallel: “She likes cooking, jogging, and reading.”
- Parallel: “She likes to cook, jog, and read.”
- Lacking parallelism: “He likes to swim and running.”
- Parallel: “He likes to swim and to run.”
- Parallel: “He likes swimming and running.”
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.”
- Lacking parallelism: “The dog ran across the yard, jumped over the fence, and down the alley sprinted.”
- Grammatical but not employing parallelism: “The dog ran across the yard and jumped over the fence, and down the alley he sprinted.”
- Parallel: “The dog ran across the yard, jumped over the fence, and sprinted down the alley.”
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.”
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.
Read the following passage. Correct any errors in parallelism that you find. Remember, non-parallel things are typically grammatically correct, but making things parallel will improve your writing style. Type your correct answer in the text frame below:
“The Bone Wars” refers to a period of intense fossil speculation and discovery in American history (1872–1892). The wars were marked by a heated rivalry between Edward Drinker Cope and Othniel Charles Marsh. At one time, Edward and Marsh were amicable: they even named species after each other. Over time, however, their relationship soured, likely due in part to their strong personalities. Cope was known to be pugnacious and possessed a quick temper. Marsh was slower, more methodical, and introverted. Eventually, each of the two paleontologists would resort to underhanded methods to try to out-compete the other in the field, resorting to bribery, theft, and destroying bones.
By the end of the Bone Wars, both Cope and Marsh were financially and socially ruined by their attempts to disgrace each other, but their contributions to science and the field of paleontology were massive. Several of Cope’s and Marsh’s discoveries are the most well-known of dinosaurs: Triceratops, Allosaurus, Diplodocus, and Stegosaurus. Their cumulative discoveries defined the then-emerging field of paleontology. Before Cope’s and Marsh’s discoveries, there were only nine named species of dinosaur in North America. Judging by pure numbers, Marsh “won” the Bone Wars: Cope discovered a total of 56 new dinosaur species, but Marsh had found 80.
- At one time, Edward and Marsh were amicable: they even named species after each other.
- In this sentence, there is both a first name and a last name used to identify different people. Unless one person commonly goes by their last name while the other goes by their first, you should use first or last names; not a mix of the two: “Cope and Marsh were. . . “
- Cope was known to be pugnacious and possessed a quick temper.
- “Was known to be” and “possessed” are both past-tense verbs, but one is a perfect tense (known) while the other isn’t. To make the sentence more parallel, you would change it to something like “Cope was known to be pugnacious and to possess a quick temper” or “Cope was pugnacious and possessed a quick temper.”
- Marsh was slower, more methodical, and introverted.
- The first to adjectives are comparatives, while introverted is not. A more parallel version of the sentence would read: “Marsh was slower, more methodical, and more introverted.”
- Eventually, each of the two paleontologists would resort to underhanded methods to try to out-compete the other in the field, resorting to bribery, theft, and destroying bones.
- Bribery and theft are both nouns, while destroying is a gerund. Changing destroying to a noun will make the sentence more parallel: “bribery, theft, and the destruction of bones.”
- Judging by pure numbers, Marsh “won” the Bone Wars: Cope discovered a total of 56 new dinosaur species, but Marsh had found 80.
- Saying “Marsh discovered 80” instead of using had found is a better fit for parallel structure.
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:
- “The inherent vice of capitalism is the unequal sharing of blessings; the inherent virtue of socialism is the equal sharing of miseries.” —Winston Churchill
- “Let every nation know, whether it wishes us well or ill, that we shall pay any price, bear any burden, meet any hardship, support any friend, oppose any foe to assure the survival and the success of liberty.” —John F. Kennedy
- “And that government of the people, by the people, for the people, shall not perish from the earth.” —Abraham Lincoln, Gettysburg Address
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.