Parallel structure is a writing technique where you use the same grammatical pattern to express two or more ideas that carry equal importance. It works at the level of individual words, phrases, or entire clauses. When you keep matching elements in the same form, your writing becomes clearer, more balanced, and easier to read. When you don’t, sentences feel lopsided, and readers stumble.
How Parallel Structure Works
The core rule is simple: don’t mix forms. If you start a list with a verb ending in “-ing,” every item in that list should use an “-ing” verb. If you begin with a noun, stick with nouns. If you open with a full clause (subject + verb), every element that follows should also be a full clause.
Here’s what that looks like in practice. Say you’re describing someone’s morning routine:
- Not parallel: She likes running, to swim, and bike rides.
- Parallel: She likes running, swimming, and biking.
The first version mixes three different grammatical forms: a gerund (running), an infinitive (to swim), and a noun phrase (bike rides). The second version picks one form and commits to it. That consistency is parallel structure.
Lists and Series
Lists are where parallel structure matters most and where errors show up most often. Anytime you string together three or more items in a sentence, each item needs to follow the same pattern. Consider this example from UNC Chapel Hill’s Writing Center:
- Not parallel: The three pillars of the Mayor’s campaign are supporting local business, reducing crime, and education.
- Parallel: The three pillars of the Mayor’s campaign are supporting local business, reducing crime, and increasing educational funding.
The first version sneaks in a lone noun (“education”) after two “-ing” phrases. The fix is straightforward: either make everything a gerund phrase or make everything a noun. A second valid correction would be: “The three pillars of the Mayor’s campaign are local business development, crime reduction, and education.” Both versions work because each item follows the same structure.
Correlative Conjunctions
Correlative conjunctions are word pairs that work together: either/or, neither/nor, not only/but also, both/and, and whether/or. Whatever grammatical form follows the first word in the pair should match the form that follows the second.
- Not parallel: She not only likes reading but also to paint.
- Parallel: She not only likes reading but also enjoys painting.
- Parallel: I would love to go to either Egypt or Italy.
- Parallel: Neither Mercury nor Venus is an inhabitable planet.
The trick with correlative conjunctions is to check what immediately follows each half of the pair. If “not only” is followed by a verb, “but also” needs to be followed by a verb in the same form. If “either” is followed by a noun, “or” should be followed by a noun.
Verb Tense Consistency
Parallel structure also applies to verb tenses. When multiple actions happen in the same time frame, they should all use the same tense. Shifting tenses mid-sentence without reason is one of the most common parallelism errors.
- Not parallel: Yesterday we walk to school but later rode the bus home.
- Parallel: Yesterday we walked to school but later rode the bus home.
Another example: “About noon the sky darkened, a breeze sprang up, and a low rumble announced the approaching storm.” All three verbs are in the simple past tense because they describe events in the same time frame. Switching one of them to present tense would break the parallel structure and confuse the reader about when things happened.
Comparisons Using “Than” or “As”
Whenever you compare two things, the elements on each side of “than” or “as” need to match grammatically. This is easy to overlook because the sentence can still sound natural even when the forms are off.
- Not parallel: Running a marathon is harder than to ride a bike.
- Parallel: Running a marathon is harder than riding a bike.
Both sides of the comparison now use the same “-ing” form, making the sentence balanced and easier to process.
Parallel Structure on Resumes
Resumes are where faulty parallelism is most visible and most costly. Each bullet point under a job title should start with the same type of word, typically a strong past-tense verb. Here’s a real example of what goes wrong:
- Not parallel: Prepared weekly field payroll / Material purchasing, expediting, and returning / Recording OSHA regulated documentation / Change orders / Maintained hard copies of field documentation
- Parallel: Prepared weekly field payroll / Handled material purchasing, expediting, and returning / Recorded OSHA regulated documentation / Processed change orders / Maintained hard copies of field documentation
The first version bounces between past-tense verbs, noun phrases, and gerunds. It reads like five different people wrote it. The corrected version opens every bullet with a past-tense action verb, giving the resume a clean, professional rhythm. Hiring managers scan resumes in seconds, and inconsistent formatting creates friction that can cost you a closer look.
Parallel Structure in Speeches and Persuasion
Beyond grammar correctness, parallel structure is a powerful rhetorical tool. It creates rhythm, builds momentum, and makes ideas memorable. Some of the most quoted lines in English rely on it.
Abraham Lincoln’s Gettysburg Address uses three parallel prepositional phrases: “government of the people, by the people, for the people.” Each phrase follows the same pattern (preposition + “the people”), and the repetition gives the line its weight. Charles Dickens used parallel past-tense verbs for a similar effect: “He laid down the carving knife and fork, put his two hands into his disturbed hair, and appeared to make an extraordinary effort to lift himself up by it.” The matched verb forms create a sequence that pulls you forward through the action.
This is why speechwriters lean so heavily on parallelism. Repeating the same structure signals to listeners that the ideas are connected and building toward something. It turns a list of points into an argument that feels inevitable.
How to Check Your Own Writing
The simplest method is to look for any sentence that contains a list, a comparison, or a correlative conjunction. Then isolate the elements that should be parallel and stack them vertically. If they don’t share the same grammatical form, you’ve found the problem.
For example, take the sentence: “The job requires creativity, attention to detail, and being organized.” Stack the three items:
- creativity (noun)
- attention to detail (noun phrase)
- being organized (gerund phrase)
The first two are noun-based, but the third switches to a gerund. Changing it to “organization” or “organizational skill” fixes the break. This vertical stacking technique works for everything from essay sentences to resume bullets to presentation slides. Once you start looking for mismatched forms, you’ll notice them everywhere, including in published writing that should have caught them.