Parallelism (Parallel Structure)

Parallelism (Parallel Structure) is a grammatical concept refers to repetition of two or more parts of a sentence take the same grammatical form.

Parallelism fosters reading comprehension because it enables readers to chunk information — elements of a sentence (e.g., words, phrase, sentence) — as coequal and related. Errors in Parallelism errors are serious because then impede communication, resulting in confused readers.

Any time you list words, phrases, or clauses in a sentence, they should have parallel structure. For example:

I like to bike, swim, and ride.

Notice that each element in the list of things that the speaker likes to do is in the same verb form. That way, it’s clear for the reader that the three elements of the sentence belong together in the same category–this list.

Inconsistent parallel becomes pretty clear in short lists, like the one above. If you say I like to bike, swimming, and I ride a lot, you are most likely to notice that these elements don’t belong together.

Because sentences can contain a variety of grammatical elements, they can have parallel structure in a number of ways.

Parallel structure with basic verbs.

Your verbs need to be in the same format.

Original: I like fishingto swim, and sunbathed.

Revised: I like fishingswimming, and sunbathing.

Revised: I like to fishto swim, and to sunbathe.

Revised: I fishedswam, and sunbathed.

Moderate error with nouns.

Listed items can all be made into nouns or verb + noun combinations.

Original: I like previewswatching movies and popcorn.

Revised: I like watching previews and movies andeating popcorn.

Revised: I like previewsmovies, and popcorn.

Other Parallelism Errors

Original: The jury deliberated about the defendant who had a motivewas belligerent, and who had no alibi.

Revised: The jury deliberated about the defendant who had a motivea belligerent attitude, and no alibi.

Revised: The jury deliberated about the defendant who had a motivewho had a belligerent attitude, and who had no alibi.

English is a varied language, so the options are infinite—just remember that all parts of your sentence should have a similar structure in order to be parallel.

Is not having parallel structure always wrong?

For the most part, yes. Usually an error with parallelism will throw off the rhythm of your sentence, leaving the reader confused but not certain why. These kinds of errors will not always interfere with comprehension, but they will affect the style of your writing, placing an undue burden on the reader as he or she struggles to decipher your intention. Unless you are making a specific point and want the reader off balance in that way, use parallel structure in your writing.

Parallel structure is established when words within a sentence are united by consistent use of grammatical forms. This stylistic element is also referred to as parallelism or parallel construction.

Why is it important to use parallel structure?

Lack of parallel structure can disrupt the rhythm of a sentence, leaving it grammatically unbalanced. Proper parallel structure helps to establish balance and flow in a well-constructed sentence; the alignment of related ideas supports readability and clarity.

Let’s look at an example:

  • Not Parallel: The President traveled to several cities meeting voters, to give speeches, and ask for campaign funds.
  • Parallel: The President traveled to several cities meeting voters, giving speeches, and asking for campaign funds.

How can a sentence be revised to reflect parallel structure?

1.Find a list within a sentence: Look for words or phrases of equal importance that are separated by commas and joined by a conjunction

Not parallel: Dr. Kall challenged his students to initiate their own learning, be creative problem-solvers, and think independently. (In this sentence, Dr. Kall wants his students to do or be three things, but the items in this list are not parallel in structure.)

2. Evaluate the word forms within the list.

  1. Do the verbs appear as infinitives (to + verb), or gerunds (-ing words)? As present tense or past tense? (Choose the voice and tense of the verb that is consistent with surrounding sentences.)
  2. Do the nouns or pronouns and their modifiers appear in consistent form?

3. Alter the words in the list to create proper parallel structure.

Parallel: Dr. Kall challenged his students to become self-motivated learners, creative problem-solvers, and independent thinkers. (In this sentence, Dr. Kall wants his students to be three things instead of a combination of being and doing. Additionally, the list follows a pattern since the nouns and adjectives all appear in parallel form.)