Parallel construction of sentences, lists, and even headings makes messages much easier for the reader to absorb. Sometimes, for the newer writer, it might be easier to think of a predictable rhythm or format when working on how to achieve parallelism. Think of the beat of poetry or songs and how it makes the words easy to remember and predict. As a writer, you can use that same structure to your advantage.

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 end in “ing,” whereas in the first sentence, two of the action words end in “ing” and one does not. While the meaning of the first sentence comes through, it’s easy to trip up over the mismatched action words (or verbs).

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 different action words. To make them parallel, the sentences should be rewritten with the same types of action words. You could argue that the first sentence is correct in that “cooking,” “jogging,” and “to read” are all grammatically valid conclusions to “She likes.” However, when you put them together, the lack of parallelism leads to an incorrect sentence.

An easy way to think about this is to make your sentence into three separate sentences:

The dog likes to run.

The dog likes to play fetch.

The dog likes to go to the dog park.

Remember how we talked about poetry or song at the beginning of this section? You can see from these three sentences that they “rhyme” in all but the last few words.

To achieve parallelism, identify where the sentences start to be different. In the example above, the sentences change when you get to the action words, after the word “to.” Therefore, what comes after “to” is what your list should be made of in order to keep a parallel structure in your sentences. Then check your parallelism by making sure that each of the items represents the same part of speech. In this case, each item–“run,” “play,” “go”–is a present-tense verb, so the parallelism works.

The dog likes to

run.

play fetch.

go to the dog park.

Here are a few more examples of parallelism in which the elements are all different lengths and types:

Jackson and Krista are cooking dinner, David and Rogelio are setting the table, and Ollie and Ron are picking up dessert. (The parallel elements of this sentence are independent clauses that could stand alone. We could make sentences out of each clause before the comma.)

Juana looked for her phone under the table, on top of the bookcase, and inside the cupboard. (The parallel elements are prepositional phrases, or words that indicate location, in this sentence.)

Mandy and Torrence watched The Godfather, Mary Poppins, and a PBS documentary about pelicans. (This may look tricky, but all of the elements in the list are nouns, or things, so the sentence is parallel.)

Parallelism can also apply to the way you talk about similar elements in general. If you’re writing a research paper that includes references to several different authors, you should be consistent in how you cite them. 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 through your entire paper. You should use the same mode of address for every person you mention. Maintaining parallelism can also keep you from unintentional bias. Referring to three physicians as Dr. Jameel Smith, Dr. Samuel Evans, and Kathy will probably not make Dr. Kathleen O’Rourke very happy.

Parallelism is really helpful when you’re making lists, tables, or outlines. Think about the difference between these two versions of a list in an internal report:

Which one is easier to follow? Which is more professional in its look and feel? Essentially, any time you have a list—whether it’s within a single sentence or has a larger scope—you should focus on parallelism.