What Is Parallel Structure In English? | Errors To Skip

If your sentence feels lumpy, parallel structure is often the fix. Readers expect items that “match” to look alike on the page and sound alike in the ear. When they don’t, meaning slows down. You reread. You lose the thread.

This guide shows what parallel structure is, where it shows up, and how to repair it fast. You’ll get patterns you can reuse in essays, emails, résumés, and outlines, in class and at work.

Parallel Structure At A Glance

Where It Shows Up	Non-Parallel	Parallel
List of verbs	She likes to hike, biking, and swims.	She likes to hike, to bike, and to swim.
List of nouns	The job needs patience, to plan, and honesty.	The job needs patience, planning, and honesty.
List of adjectives	The lecture was clear, with humor, and concise.	The lecture was clear, humorous, and concise.
Paired ideas	He wanted success, not failing.	He wanted success, not failure.
Correlative pair	She not only studied hard but also aced the test.	She not only studied hard but also worked steadily.
Comparisons	Writing a draft is easier than to revise.	Writing a draft is easier than revising.
Headings in outlines	Choose Topic / Research / To Draft	Choose Topic / Research Sources / Draft Paper
“To” + verb series	To read, writing, and to edit	To read, to write, and to edit

What Is Parallel Structure In English? In Plain Terms

Parallel structure (also called parallelism) means that items doing the same job in a sentence use the same grammatical shape. When you line up nouns with nouns, verbs with verbs, and clauses with clauses, the reader can process the list in one smooth pass. Purdue OWL defines parallel structure as using the same pattern of words to show that two or more ideas have the same level of importance. Purdue OWL parallel structure.

A simple way to think about it: if you can point to two or more parts and say “these belong together,” they should look alike.

Parallel Structure Works At Three Levels

• Word level: matching nouns, verbs, adjectives, or -ing forms.
• Phrase level: matching prepositional phrases, infinitive phrases, or gerund phrases.
• Clause level: matching full clauses, often joined with “and” or “or.”

In school writing, word and phrase level issues show up most. Clause level matters in longer sentences, thesis statements, and research summaries.

Why Parallel Structure Makes Writing Easier To Read

Parallel structure is less about “rules” and more about reader rhythm. When the pattern stays steady, the reader predicts what comes next. That prediction saves mental effort, so the point lands faster.

It also keeps your meaning fair. If one list item is a full clause and the next is a single word, the sentence can feel like it’s comparing unequal things. Parallel wording signals equal weight.

Places Teachers And Editors Check First

• Bulleted lists inside paragraphs
• Thesis statements with multiple claims
• Topic sentences that name several points
• Résumé bullet points
• Headings and subheadings in outlines

That last one is sneaky. If your outline headings don’t match, your paper often wanders. Purdue OWL also points out that headings within a level should keep the same structure. It’s one of the quickest checks you can do before printing.

Common Parallel Structure Errors You Can Spot In Seconds

Most parallel errors come from mixing three common forms: infinitives (“to write”), gerunds (“writing”), and base verbs (“write”). Pick one, then stick with it through the series.

Mixing “To” Verbs And “-ing” Verbs

Watch for a list that starts with “to” and then drifts.

• Non-parallel: “My plan is to study, practicing problems, and to rest.”
• Parallel: “My plan is to study, to practice problems, and to rest.”

Mixing Nouns With Actions

Another classic slip: two nouns, then a verb idea.

• Non-parallel: “The course builds confidence, patience, and how to speak up.”
• Parallel: “The course builds confidence, patience, and courage.”

Breaking Comparisons

Comparisons like “than” and “as…as” want the same grammatical form on both sides.

• Non-parallel: “Drafting is easier than to edit.”
• Parallel: “Drafting is easier than editing.”

Unbalanced Correlative Conjunctions

Pairs like “either…or,” “neither…nor,” and “not only…but also” act like rails. The pieces after each rail should match.

• Non-parallel: “She not only proofread the essay but also the citations.”
• Parallel: “She proofread not only the essay but also the citations.”

A Fast Test: Find The “Join Words,” Then Match The Forms

When you’re unsure, start by locating the join word: “and,” “or,” “but,” “than,” “as,” or a paired set like “either…or.” Then ask two questions:

1. What grammatical form comes right after the join word?
2. Do the other joined parts share that same form?

If not, rewrite the odd one out so it matches the rest. You’re not changing your idea. You’re changing the shape.

Fixing Parallel Structure Step By Step

Here’s a clean repair routine you can use during revision. It works on sentences, list items, and headings.

Step 1: Box The Series

Put brackets around the items that belong together. If you can’t tell what belongs in the series, the sentence may be trying to do too much.

Step 2: Name The Pattern

Say the pattern out loud: “noun + noun + noun,” “to-verb + to-verb + to-verb,” or “-ing + -ing + -ing.” Naming it keeps you from drifting mid-list.

Step 3: Rewrite The Offender, Not The Whole Sentence

Often you only need to change one word. Swap “to revise” to “revising,” or swap “planning” to “to plan.” Keep the rest.

Step 4: Read It Like A Metronome

Read the series with a steady beat. If one item takes longer to say, it may be built differently. Tighten it until each part hits with the same cadence.

Parallel Structure In Essays, Emails, And Résumés

Parallel structure matters more when you’re stacking claims or selling a point. These contexts show up in school and work all the time.

Thesis Statements With Multiple Claims

A thesis that lists three reasons should keep the three reasons in the same form.

• Non-parallel: “This policy saves money, reducing waste, and it improves safety.”
• Parallel: “This policy saves money, reduces waste, and improves safety.”

Professional Emails With Action Lists

When you ask someone to do three tasks, parallel phrasing lowers the chance they miss one.

• Non-parallel: “Please review the draft, adding comments, and send it back.”
• Parallel: “Please review the draft, add comments, and send it back.”

Résumé Bullet Points That Read Like A Set

Bullets under one job title should start the same way. If the first bullet begins with a past-tense verb, keep that style across the list.

• Non-parallel: “Managed schedules; team training; and I handled customer calls.”
• Parallel: “Managed schedules, trained the team, and handled customer calls.”

Parallel Structure With Correlative Pairs

Correlative conjunctions are pairs that work together: “both…and,” “either…or,” “neither…nor,” “not only…but also.” A quick trick is to place the pair right in front of the matching pieces.

Cambridge Dictionary defines parallelism as “the use of matching sentence structure…so as to balance ideas of equal importance.” Cambridge Dictionary parallelism is a neat short definition if you want a citation for class notes.

Common Repair Moves

• Move the pair: “She proofread not only the essay but also the citations.”
• Match the form: “He is either studying at home or working at the library.”
• Keep modifiers aligned: “We value both clear writing and careful editing.”

Parallel Structure In Longer Sentences

Long sentences hide parallel errors because the matching parts sit far apart. The fix is still the same: locate the join word, then match the grammar on both sides.

Parallel Clauses With “That”

If you stack “that” clauses, keep the clause openings alike.

• Non-parallel: “She argued that the data was flawed and the sample size was too small.”
• Parallel: “She argued that the data was flawed and that the sample size was too small.”

Parallel Prepositional Phrases

Prepositional phrases often appear in sets: “in the lab,” “in the field,” “in the report.” Don’t switch to a clause mid-set.

• Non-parallel: “We met in the library, after class, and we talked online.”
• Parallel: “We met in the library, after class, and online.”

Parallel Lists After A Colon

Colons often introduce a list. Once you commit to a form, keep it steady through every item. If the first item is a noun phrase, keep noun phrases. If the first item is an action, keep actions. This is handy in academic writing, where you might list methods, limits, or results in one sentence. Read the list without the opening clause. If the items still sound like they belong in one family, the structure is parallel.

Table Of Quick Fix Patterns

Pattern To Choose	Use It When	One Clean Template
to-verb series	You’re stating plans or goals	to read, to write, to revise
-ing series	You’re naming activities	reading, writing, revising
base-verb series	You’re giving instructions	read, write, revise
noun series	You’re listing things or traits	clarity, accuracy, fairness
adjective series	You’re describing one noun	clear, concise, consistent
clause series	You’re stacking full ideas	that we planned, that we tested
comparison	You use “than” or “as…as”	easier than revising
correlative pair	You use either/or, both/and	either to study or to rest

A Practice Routine That Builds The Habit

Parallel structure gets easier once your eye learns to spot the mismatch. Try this short routine on your next draft.

Read One Paragraph Only For Lists

Scan for commas, bullets, and “and/or.” Each one is a parallelism checkpoint. Fix those, then move on.

Turn Each List Into A Mini Outline

Write the first word of each list item on its own line. Do they match in form? If one starts with “to” and the next is a noun, rewrite until they line up.

Use A “Same Job, Same Form” Note In The Margin

When you revise, leave yourself a quick note: “Same job, same form.” It’s short enough to stick.

Mini Checklist Before You Submit

• All list items share the same grammatical form.
• Comparisons match form on both sides of “than” and “as.”
• Correlative pairs sit right before the matched parts.
• Outline headings start with the same part of speech within a level.
• Bullets under one résumé role start the same way.

Answering The Question Directly

If you came here asking, “what is parallel structure in english?”, here’s the practical takeaway: match the grammar of items that belong together, then read the series out loud. If it keeps the same beat, you’re set.

One more time, in plain terms: “what is parallel structure in english?” It’s the habit of keeping lists and paired ideas in the same form, so your writing reads clean and fair.