Parallelism is “the use of matching sentence structure, phrases, or longer parts so as to balance ideas of equal importance” (Cambridge Dictionary Online, 2019).

Parallel structure is an important component of good writing. It ensures that your text flows smoothly and that your grammatical forms are consistent. Done well, parallelism can give your writing more impact.

Tip: 

Words in a series or in a compound sentence should be written in the same tense and in the same style of speech. In the examples below, the italicized words and phrases are in parallel form, and the bolded ones are not.

• Correct: In the summer, I like to go swimming, camping and hiking.
• Incorrect: In the summer, I like to go swimming, camping and for hikes.

 

• Correct: After we completed the assignment, we waited for the grade.
• Incorrect: After we completed the assignment, we wait for the grade.

 

• Correct: She not only corrected my grammar, but also corrected my spelling.
• Correct: She corrected not only my grammar, but also my spelling.
• Incorrect: She not only corrected my grammar, but also my spelling.

 

• Correct: The participants were told to make themselves comfortable, to read the instructions, and to ask about anything they did not understand.
• Incorrect: The participants were told to make themselves comfortable, to read the instructions, and that they should ask about anything they did not understand (example extracted from APA, 2010, p. 86).

References:

American Psychological Association. (2010). Publication Manual of the American Psychological Association (6th ed.). Washington, DC: American Psychological Association.

Parallelism. (2019). In Cambridge Dictionary Online. Retrieved from https://dictionary.cambridge.org/dictionary/english/parallelism