Parallel structure

To make the ideas in your sentences clear and understandable, you need to make your sentence structures grammatically balanced (i.e. parallel). This means that ideas in a sentence or paragraph that are similar should be expressed in parallel grammatical form (e.g. Jessie likes running, swimming and painting not Jessie likes running, swimming and to paint).

Parallel grammatical form is needed for:

Grammar checkers do not flag faulty parallelism. Computers cannot assess whether ideas are parallel in meaning, so they will not catch faulty parallelism. Check the rules for parallel structure and check your sentences as you write and when you proofread your work.

Lists of words, phrases and clauses

When ideas are presented in a series or a list, the same parts of speech should be used to ensure parallel structure. This applies whether the list consists of single words, phrases or clauses—single words should be balanced with single words, phrases with phrases and clauses with clauses.

Single words should be matched with single words of the same type (e.g. all nouns, all adverbs, all adjectives).

INCORRECT: The lecturer asked the students to speak in tutorials clearly, in a loud voice and not to be rude.

CORRECT: The lecturer asked the students to speak in tutorials clearly, loudly and politely.

Groups of words (phrases) should be matched with word groups of the same pattern (e.g. noun phrases beginning with verb +-ing, prepositional phrases).

INCORRECT: Success at university depends on attending classes, reviewing your notes and to keep up with your readings.

CORRECT: Success at university depends on attending classes, reviewing your notes and keeping up with your readings.

Clauses should be matched with clauses of the same pattern (e.g. noun clauses, adverbial clauses, adjectival clauses).

INCORRECT: The lecturer expected that the students would present the seminar, be using PowerPoint presentations and they would answer questions from the audience.

CORRECT: The lecturer expected that the students would present the seminar, use a PowerPoint presentation and answer questions from the audience.

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Parallel ideas connected by conjunctions

Ideas that are joined with conjunctions need to be parallel in structure. By using similar grammatical forms to express equal ideas, your writing will be smooth and your writing style will improve.

Type 1. Like ideas joined by ‘and’, ‘but’, ‘or’, ‘nor’, ‘for’, ‘so’, ‘yet’

  • Your oral presentation should use PowerPoint slides and refer to handouts.
  • She failed the essay but passed the final exam.
  • Her oral presentation was good, yet her essay was poor.

Type 2. Comparisons joined by ‘than’ or ‘as’

  • Learning at university is more difficult than studying at high school.
  • Writing assignments is as important as sitting exams.

Type 3. Ideas joined by pairs of conjunctions ‘both … and’, ‘either … or’, ‘neither … nor’, ‘not only … but also’, ‘whether … or’

  • Both the lecturers and the students protested about the changes in assessment policy.
  • The students were not only hard-working but also community-minded.
  • The assignment tasks need to be either submitted electronically or posted to the university assessment centre.

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Essay headings and tables of contents

Assignment headings and tables of contents are easier to read if the headings at the same level have the same grammatical form.

  • First level headings should use the same structure as other first level headings.
  • Second level headings should use the same structure as other second level headings.
  • Third level headings should use the same structure as other third level headings, and so on.
Table of Contents

I. Introduction to Academic SkillsFirst level heading – bold 12pt

A. Analysing the question

B. Researching the topic

II. Essay Structure

A. Writing paragraphsSecond level heading – italics 12pt

1. Topic sentences

2. Body

3. ConclusionThird level heading – normal 11pt

B. Reviewing

1. Drafts

2. Finished product

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Check your understanding

How can the following sentence be improved? Jessie likes running, swimming and to paint.
By adopting a parallel structure: Jessie likes running, swimming and painting. More information
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