What is parallel structure in writing?
Definition of parallel structure
Parallel structure, also known as parallelism, is the repetition of a chosen grammatical form within a sentence. By using the same pattern of words to show that two or more ideas have the same level of importance, writers create symmetry, improve clarity, and enhance the professional rhythm of their prose.
Parallel vs. faulty structure
To understand parallel structure, it is helpful to see how it differs from faulty parallelism. Faulty structure occurs when a writer breaks the established grammatical pattern in a series or list.
Key differences at a glance
| Dimension | Parallel Structure | Faulty Parallelism |
|---|---|---|
| Goal | Create balance and rhythm | Convey information without symmetry |
| Grammatical Form | Uniform (all nouns, all verbs, etc.) | Mixed (noun + verb + phrase) |
| Readability | High; easy to follow | Low; feels disjointed or clunky |
| Impact | Emphasizes equal importance | Can confuse the reader's focus |
| Typical Use | Lists, comparisons, and series | Usually an accidental error |
| Professionalism | Standard in academic writing | Sign of unpolished drafting |
Common types of parallel structure
Parallelism can be applied to various parts of speech. In academic essays, you will most frequently use it with gerunds, infinitives, and clauses.
### Parallel gerunds
If you start a list with an -ing word, every item in that list must be an -ing word. For example: 'The study focused on collecting data, analyzing trends, and reporting findings.'
### Parallel infinitives
When using 'to' before a verb, maintain that structure throughout. For example: 'The goal was to increase efficiency, to reduce waste, and to improve morale.'
### Parallel clauses
Parallelism also applies to longer phrases. For example: 'The professor argued that the theory was outdated, that the evidence was flawed, and that the conclusion was invalid.'
Parallel structure in essay writing
Observe how parallel structure transforms a disjointed sentence into a polished academic statement. **Faulty Structure:** The industrial revolution led to the growth of cities, people moved to urban areas, and more goods were produced. *Annotation: This mixes a noun phrase (growth of cities), a clause (people moved), and a passive clause (goods were produced).* **Correct Parallel Structure:** The industrial revolution led to the growth of cities, the migration of laborers, and the expansion of manufacturing. *Annotation: Each item is now a consistent noun phrase (The [Noun] of [Noun]), making the sentence balanced and authoritative.*
The list check
Whenever you use a coordinating conjunction like 'and,' 'or,' or 'but,' stop and check the words on either side. If the first part of your list is a verb, the second part should be a verb in the same tense. If the first part is a prepositional phrase, the second should be as well. This simple check eliminates 90% of parallelism errors.
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