Effective writing requires a certain amount of variety. You vary word choice, for example, as well as sentence length and structure. But effective writing is also patterned.
Parallelism is the way that we pattern writing so that similar elements in a sentence are grammatically equivalent. That is, if there are two or more subjects, they are all nouns or noun phrases. If there are two or more verbs, they are all of the same form. If there are two prepositional phrases, they are similar in form (with no verbs snuck in to transform one of them into a clause).
Achieving parallelism smoothes out writing and increases its impact. For example, without their subject-verb pattern, these words by Confucius would not have nearly the impact they do:
"I hear and I forget. I see and I remember. I do and I understand."
What he means, of course, is "We learn best by doing." But there would be nothing particularly memorable about saying so!
Parallelism is so important to the smooth flow of ideas that comedians sometimes deliberately violate the rules of parallelism in order to make us laugh. Compare the elegance of Confucius's parallel expression above to Dave Barry's unexpectedly non-parallel statement below:
"Skiing combines outdoor fun with knocking down trees with your face."
If we wanted to make this expression properly parallel, the two elements that follow "Skiing combines" should be grammatically equivalent: "Skiing combines outdoor fun [adjective-noun] with physical danger [adjective-noun]." (But you wouldn't have smiled.)
Unless you are writing comedy, then, follow these rules:
Coordinating conjunctions must connect like-patterned things. This sentence uses parallel compound subjects:
High temperature [adjective-noun] and low humidity [adjective-noun] are typical of summers in Chico.
This parallel structure is better than, for example, "High temperatures and the lowness of the humidity are typical of summers in Chico."
The following example joins parallel compound verb forms:
We hiked along the creek to Bear Hole, where we gratefully dropped [past tense verb] our daypacks, shed [past tense verb] our clothes, and plunged [past tense verb] into the water.
If we had not taken care to construct parallel verbs, we might have said, "We hiked along the creek to Bear Hole, where we gratefully dropped our daypacks, were shedding our clothes, and plunged into the water."
The following sentence uses parallel prepositional phrases, parallel verbs, and parallel direct objects:
Along the Maidu Trail [prepositional phrase] and around Horseshoe Lake, [prepositional phrase] people were walking [progressive verb] or running [progressive verb] their retrievers [noun] and Labradors [noun].
A non-parallel expression is clumsier: "Along the Maidu Trail people were walking or ran their dogs, which were mostly labs and retrievers, and around Horseshoe Lake we saw them, too."
This example uses parallel infinitives (to + verb, functioning as a noun):
In the summer we love to swim [infinitive/noun] at Five Mile and to hike [infinitive/noun] in Upper Bidwell Park.
(It would be just as correct to eliminate the second "to" as long as the roots of the infinitives were similar: "In the summer we love to swim at Five Mile and hike in Upper Bidwell Park.")
The following sentence uses parallel gerunds (-ing words functioning as nouns) as subjects:
Swimming [gerund/noun], hiking [gerund/noun], and stargazing [gerund/noun] are great ways to pass summer evenings in Chico.
Gerunds should not be combined with infinitives in sentences requiring parallel structure: "Swimming, hiking, and to stargaze are great ways to pass summer evenings in Chico."
In correlative pairs (either...or, not only...but also, neither...nor, both...and) whatever grammatical element follows the first part must follow the second as well.
We could either leave [present tense verb] at dusk or wait [present tense verb] until the planetarium opened.
The sound of the coyotes yammering in the distance was not only very haunting [adverb-adjective] but also somehow comforting [adverb-adjective].
A non-parallel version might be, "The sound of the coyotes yammering in the distance was not only rather haunting but also comforted us in some strange way."
Other connecting words similar to correlative pairs benefit from and sometimes require parallel structure. Use parallel structure when comparing (more than, less than) or contrasting (rather [this] than [that], instead of), and in expressions such as "from [this] to [that]"
Even more than lunch [noun], I would like a cold drink [noun].
A non-parallel version is clumsier (though not technically incorrect): "Even more than lunch, I would like to get something to drink."
They decided that they would rather tour [present tense verb] the brewery than visit [present tense verb] the art glass factory.
Here is a version using non-parallel verbs following "rather...than": "They decided that they would rather tour the brewery than be visiting the art glass factory."
Another characteristic of parallel expression in correlative pairs is that the two parts of the expression are developed similarly; that is, each part contains approximately the same amount of detail:
I prefer dancing [noun] to drinking [noun].
The parallel nouns in this example are both gerunds. We could have said, "I prefer dancing to a bunch of drunks who can't balance even on two legs." The point is rather the same, but the nouns are of different types and the two halves of the expression are unevenly developed: the second half is developed with more enthusiasm than the first half.
Series, lists, and outlines
In sentences, items in a series need to be parallel in form:
I'm registered for economics, drafting, and Spanish [parallel nouns].
Compare to this: "I'm registered for economics, to learn drafting, and practicing Spanish." This incorrect, non-parallel version combines a prepositional phrase, an infinitive phrase, and a gerund.
The following sentence contains a single subject and compound parallel verbs:
The tutors can explain the assignment, help you locate background material, and give you tips for citing your sources [parallel verb forms].
The verbs are parallel in form and share the single subject, tutors. Compare this with the following: "The tutors can explain the assignment, help you locate background material, and you learn valuable tips for citing your sources." Even though the third verb looks similar, sticking in a second subject (you) breaks the pattern.
Series items are not necessarily verbs or nouns. The following example uses a series of parallel modifiers:
Marketing should consider whether the plan is feasible, impractical, or impossible [parallel adjectives].
The above example is easy to understand compared to this: "Marketing should consider the feasibility of the plan, as well as whether it is impractical or if we should simply consider it impossible."
Items in lists require parallel form, whether they occur in a sentence following a colon or in a bulleted list (frequently used by business writers):
Be sure you bring all the essentials: sunscreen, insect repellent, water, snacks, fire starter, whistle, emergency shelter, first aid kit, and extra clothing [parallel nouns].
In the following non-parallel form, extra verbs break the pattern (and, worse, create comma splices): "Be sure you bring all the essentials: sunscreen, insect repellent is important, water, snacks, fire starter is useful, especially the newer magnesium ones, whistle, emergency shelter, first aid kit, and you never know when you'll need a change of clothing."
Bulleted lists should always begin with parallel forms.
College outreach representatives should be able to perform these tasks:
- Identify the special needs of the at-risk high school population
- Formulate a plan that addresses those needs
- Communicate the plan effectively to high school counselors [parallel verb phrases]
The bullets can be written as parallel verb or noun phrases, prepositional phrases, or even complete sentences. (Write the introductory sentence so that it logically and grammatically leads into whatever list follows. For example, the sentence "College outreach representatives should have these characteristics:" could not logically introduce the above example, since the list is not one of personal characteristics.)
The headings of formal outlines (that is, outlines that are to be turned in as part of an assignment rather than used for personal reference and study) require parallel form:
I. Things to do in Bidwell Park [noun phrase
A. Swim in Big Chico Creek [verb phrase]
1. The water can be cold early in the summer.
2. Some of the swimming holes can be dangerous.
3. Sycamore Pool has lifeguards in the summer. [full sentences]
B. Hike in Upper Park [verb phrase]
1. Early morning is a cooler time.
2. There is very little shade most of the way.
3. The views are spectacular. [full sentences]
II. Things to do in downtown Chico [noun phrase]
Notice that the corresponding levels of the outline are parallel with each other, although not every level is parallel to every other level. The main headings I and II are noun phrases. Headings A and B are verb phrases; heading C would also have been a verb phrase. On the other hand, the details 1, 2, and 3 are all complete sentences. You may use phrases or sentences at any level, as long as you keep corresponding items in each level parallel in structure.
To achieve parallelism, try skimming your papers for coordinating conjunctions such as and and or. Check the sentence elements on both sides of the conjunction to see if they are parallel in form. If they are not, revise those sentences to achieve parallel structure. If you are unsure whether the elements are parallel (you might discover you need a brush-up on basic parts of speech, for example), underline them. Ask your instructor or bring them to a tutor for help. (For more on parts of speech, see the TIP Sheet The Eight Parts of Speech.)
If you have a visual learning preference, try writing the sentence parts requiring parallel structure in columns. Check to see if the elements are parallel. (Once you have taken the words out of their context, though, avoid mistaking things like gerunds, swimming, for verbs, were swimming).
If you have a preference for auditory learning, try reading aloud, listening for patterns of sound. This may help you find awkward places that reveal lack of parallel structure. (Reading aloud is a useful proofreading technique anyway, since it forces you to slow down.) For practice in discerning the rhythms parallelism creates, try reading aloud some of the examples below.
Speechwriters and orators know the impact of parallel expression. For example, American abolitionist Frederick Douglass said this in 1886:
"Where justice is denied, where poverty is enforced, where ignorance prevails, and where any one class is made to feel that society is in an organized conspiracy to oppress, rob, and degrade them, neither persons nor property will be safe."
British statesman Winston Churchill said this:
"The empires of the future are the empires of the mind."
It just does not have the same impact to say, "The empires of the future will be mental"! In fact, Churchill had a positive genius for parallelism:
"We shall not flag or fail. We shall go on to the end. We shall fight in France. We shall fight on the seas and oceans. We shall fight with growing strength in the air. We shall defend our island, whatever the cost may be. We shall fight on the beaches. We shall fight on the landing grounds. We shall fight in the fields and in the streets. We shall fight in the hills. We shall never surrender."
American author Henry David Thoreau, Chinese philosopher Lao-tzu, American civil rights activist Martin Luther King Jr., Chilean poet Pablo Neruda, former Costa Rican president Oscar Arias Sanchez-almost any quotation search will turn up dozens of examples of masterful use of parallel language.
You may not aspire to change the course of history; you may just want to improve this semester's English grade. Achieving parallelism is sometimes more art than science, but with practice, you can achieve a degree of parallelism that will smooth out your writing at the very least, or-who knows?-change the world.