Using parallelism to write balanced sentences

In English grammar, parallelism (also called parallel structure or parallel construction) is the repetition of the same grammatical form in two or more parts of a sentence.

Not parallelParallel
I like to jog, bake, paint, and watching movies.I like to jog, bake, paint, and watch movies.

I like jogging, baking, painting, and watching movies.

Maintaining parallel structure helps you avoid grammatically incorrect sentences and improves your writing style. Although lack of parallelism is not always strictly incorrect, sentences with parallel structure are easier to read and add a sense of balance to your writing.

Parallel construction is most commonly used in sentences containing elements that appear in a series or in a pair. It is also applied to headings and outlines in academic writing.

Elements in a Series

Use parallel construction when items in a series have an equal level of importance. These items are usually joined by commas or semicolons along with and or or.

Parallel words

On the word level, a noun should be grouped with other nouns, an adjective with other adjectives, and so on.

Not parallelParallel
The company is looking for a candidate who is friendly, organized, meticulous, and is going to arrive to work on time.The company is looking for a candidate who is friendly, organized, meticulous, and punctual.

When a series is composed of verbs, do not mix forms. For example, mixing an infinitive (a verb beginning with to) with a gerund (a verb form ending in -ing) breaks parallel structure.

Not parallelParallel
The participants in the workshop learned how to communicate, negotiate, and working collaboratively for the most effective outcome.The participants in the workshop learned how to communicate, negotiate, and work collaboratively for the most effective outcome.

The participants in the workshop learned about communicating, negotiating, and working collaboratively for the most effective outcome.

Parallel phrases

Parallel structure should be used to balance a series of phrases with the same grammatical structure.

For example, avoid mixing noun phrases with verb phrases.

Not parallelParallel
Initial trials showed that exposure to the chemical caused memory problems, intermittent dizziness, and deters sleep.Initial trials showed that exposure to the chemical caused memory problems, intermittent dizziness, and insomnia.

As with a series of verbs, a series of verb phrases should use parallel forms. Do not mix phrases based on an infinitive with phrases based on -ing verbs.

Not parallelParallel
Her main duties were answering phone calls, filing records, and to conduct visitor surveys.Her main duties were answering phone calls, filing records, and conducting visitor surveys.

Parallel clauses

Parallelism is also applicable to a series of clauses in a sentence.

Not parallelParallel
The report card stated that the student often talked in class, that he bullied other students, and rarely finished his homework.The report card stated that the student often talked in class, that he bullied other students, and that he rarely finished his homework.

The report card stated that the student often talked in class, bullied other students, and rarely finished his homework.

Lists after a colon

A list that follows a colon should always have parallel elements.

Not parallelParallel
Mainstream economists have attributed the recession to several key causes: deregulation policies, spike in interest rates, manufacturing orders declining, and the emergence of asset bubbles.Mainstream economists have attributed the recession to several key causes: the enactment of deregulation policies, the spike in interest rates, the decline in manufacturing orders, and the emergence of asset bubbles.

Mainstream economists have attributed the recession to several key causes: deregulation policies, high interest rates, low manufacturing orders, and asset bubbles.

Elements in Pairs

Use parallel construction when a sentence contains a pair of connected ideas.

Pairs can be connected by coordinating conjunctions, which include and, nor, but, or and yet.

Not parallelParallel
She planned to collect data by either using an online survey or phone interviews.She planned to collect data by either using an online survey or conducting phone interviews.

She planned to collect data through either online surveys or phone interviews.

Use parallel structure when a pair of ideas are linked by a correlative conjunction, such as not onlybut also, either…or, and neither…nor.

Not parallelParallel
His paper argues that the distinctive divergence in the two artists’ styles was not only shaped by their mutual rivalry but also because of the idiosyncratic tastes of patrons.His paper argues that the distinctive divergence in the two artists’ styles was shaped not only by their mutual rivalry but also by the idiosyncratic tastes of patrons.

The same rule applies to pairs connected by a word of comparison, such as over, than or as.

Not parallelParallel
He prefers movie nights at home over going to loud house parties.He prefers movie nights at home over loud house parties.

He prefers hosting movie nights at home over going to loud house parties.

Outlines and headings

Headings that divide a paper into sections should be parallel. Likewise, parallel structure should be applied to elements in paper outlines.

Not parallelParallel
  1. Origin of homeopathy
  2. Initial reception
  3. Rising to popularity in the 19th century
  4. Recent studies show lack of evidence
  1. Origin of homeopathy
  2. Initial reception
  3. Rise to popularity in the 19th century
  4. Lack of evidence in recent studies
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Amy Luo

Amy has a master’s degree in History of Art and has been working as a freelance writer and editor since 2014. She is passionate about helping people communicate clearly and effectively.

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