GMAT Sentence Correction Parallelism: Your Ultimate Guide to Flawless Answers

GMAT Sentence Correction Parallelism: Your Ultimate Guide to Flawless Answers

Hey there! If you’re tackling the GMAT, you’ve probably felt that little twinge of frustration staring at a Sentence Correction question, right? It’s like the test makers are trying to trick you with words that almost sound right. Well, one of the biggest and most common culprits behind those tricky questions is something called parallelism. And let me tell you, once you get a handle on it, it’s like a superpower for your GMAT score. Ready to chat about it over a virtual coffee?

You see, the GMAT loves to test whether you can spot structural consistency in sentences. It’s not just about grammar rules; it’s about clarity, elegance, and making sure your ideas flow logically. Parallelism is all about ensuring that elements in a sentence that serve the same grammatical function are presented in the same grammatical form. Sounds a bit fancy, but trust me, it’s quite intuitive once you get the hang of it. This guide is going to break down everything you need to know, giving you practical tips and real-world GMAT-style insights so you can nail those parallelism questions every single time.

What Exactly Is Parallelism and Why Does the GMAT Care So Much?

Imagine you’re making a shopping list. You wouldn’t write “milk, eggs, and to buy bread,” would you? No, you’d write “milk, eggs, and bread.” All nouns. Or perhaps “running, swimming, and cycling.” All verbs in their -ing form. That, my friend, is parallelism in its simplest form. It’s about balance and consistency. The GMAT cares because good writing is clear writing, and parallel structures make sentences easier to read, understand, and less ambiguous.

When elements in a sentence are parallel, they share the same grammatical structure. This applies to words, phrases, and even clauses. If you’re listing items, comparing things, or using certain connecting words, the GMAT expects those elements to be structurally matched. Think of it like a neatly organized closet: everything has its place, and similar items are grouped together. Messy closets (and messy sentences) just don’t work as well.

The Basic Rule: Noun with Noun, Verb with Verb…

This is your golden rule. If you have a list of things, make sure they all “match.”

• If one item is a noun, the others should be nouns.
• If one item is an infinitive (to + verb), the others should be infinitives.
• If one item is a gerund (verb + -ing), the others should be gerunds.
• If one item is an adjective, the others should be adjectives.

Let’s look at a simple example:

Incorrect: “He likes running, swimming, and to bike.”

See the problem? “Running” and “swimming” are gerunds, but “to bike” is an infinitive. They’re not parallel. Your ear probably cringes a bit, right?

Correct: “He likes running, swimming, and biking.” (All gerunds)

Correct: “He likes to run, to swim, and to bike.” (All infinitives)

Both are grammatically correct and parallel. The GMAT will often give you options that mix these up, and your job is to spot the mismatch.

Key Situations Where Parallelism Appears

Parallelism isn’t just about simple lists. The GMAT hides it in various sentence structures. Knowing where to look is half the battle!

Lists and Series

This is probably the most common place you’ll find parallelism tested. When you have three or more items separated by commas and joined by a conjunction (usually “and” or “or”), every item needs to be in the same grammatical form.

Example: “The company’s success was due to its innovative products, aggressive marketing campaigns, and efficient distribution network.”

Here, “innovative products,” “aggressive marketing campaigns,” and “efficient distribution network” are all noun phrases. Perfect parallel structure!

GMAT Trap: “The committee decided to discuss the proposal, analyzing the budget, and would vote on the amendment.”

Can you see the issue? “to discuss” (infinitive phrase), “analyzing” (gerund phrase), and “would vote” (verb phrase with modal). A total mess!

Corrected: “The committee decided to discuss the proposal, to analyze the budget, and to vote on the amendment.” (All infinitive phrases).

Comparisons (A vs. B)

When you compare two things, those two things need to be comparable, not just in meaning, but in grammatical structure. Keywords here are “than,” “as…as,” “like,” “unlike,” and sometimes “rather than.”

Incorrect: “Her new job offers more opportunities than her old job paid.”

This is comparing “opportunities” (a noun) with “her old job paid” (a clause). Not parallel!

Correct: “Her new job offers more opportunities than her old one did.” (Comparing opportunities to opportunities, with “did” implying “offered”).

Correct: “Her new job offers more opportunities than her old job.” (Comparing opportunities to job implicitly, or explicitly if we say “than her old job’s opportunities”).

The key is that the two items on either side of the comparison word must be grammatically equivalent. If you’re comparing a noun, compare it to another noun. If you’re comparing a clause, compare it to another clause.

Correlative Conjunctions

These are pairs of conjunctions that absolutely demand parallel structure. They’re like inseparable twins, and whatever grammatical form follows the first part must also follow the second part. Get familiar with these:

• both…and
• either…or
• neither…nor
• not only…but also
• whether…or
• as…as (also used for comparisons)

Let’s check an example:

Incorrect: “The new policy affects not only employees but also customers felt the impact.”

After “not only” we have a noun. After “but also” we have an entire clause. No good!

Correct: “The new policy affects not only employees but also customers.” (Noun vs. Noun)

Correct: “Not only did the new policy affect employees, but it also affected customers.” (Clause vs. Clause)

Another classic GMAT trick:

Incorrect: “She wants either to travel or a new job.”

Here, “to travel” is an infinitive phrase, and “a new job” is a noun phrase. They don’t match!

Correct: “She wants either to travel or to find a new job.” (Infinitive phrase vs. Infinitive phrase)

Practical Tips and Tricks for Spotting Parallelism Errors

Alright, you know what parallelism is and where it likes to hide. Now, how do you find it quickly and accurately under timed GMAT conditions?

Look for “Trigger Words”

These are your red flags. Whenever you see these words, your parallelism antenna should go up immediately:

• Conjunctions: and, or, but
• Comparison words: than, as, like, unlike, rather than
• Correlative Conjunctions: both…and, either…or, neither…nor, not only…but also, whether…or

These words almost always signal that something needs to be parallel.

“Draw the Line”

This is a visual trick that helps. When you see a list or a comparison, mentally “draw a line” before and after the trigger word (or between the elements). Are the structures on either side of the line identical? If not, you’ve found your error.

Example: “He enjoys running, swimming, and biking.”

Running | swimming | biking. All gerunds. Good!

Example: “He enjoys running, swimming, and to bike.”

Running | swimming | to bike. Gerund | Gerund | Infinitive. Problem!

Trust Your Ear (with caution!)

Sometimes, an unparallel sentence just sounds awkward. This can be a good first filter, but don’t rely on it exclusively. The GMAT can craft plausible-sounding incorrect sentences, so always back up your “ear test” with a structural check.

Identify the “Core”

When a sentence is long and complex, strip it down. What are the essential elements being listed, compared, or joined by correlative conjunctions? Focus on those core parts and ignore the modifiers for a moment. Once the core is parallel, then you can add back the descriptive phrases, ensuring they attach correctly.

Practice, Practice, Practice

There’s no substitute for seeing these patterns repeatedly. The more GMAT Sentence Correction questions you do, the faster you’ll become at recognizing parallelism errors. It will become second nature.

Common Parallelism Pitfalls

The GMAT loves its tricky little ways to test parallelism. Watch out for these common traps:

Verb Forms: Gerunds vs. Infinitives

This is probably the most frequent parallelism error on the GMAT. As we saw, mixing “-ing” verbs (gerunds) with “to + verb” (infinitives) is a big no-no when they’re in a parallel structure. Make sure you pick one form and stick with it for all parallel elements.

Pronouns and Possessives

Be super careful when comparing things involving pronouns or possessives. For example, you can’t compare someone’s ideas with another person, but rather with that person’s ideas.

Incorrect: “His ideas are more innovative than her.” (Comparing ideas to a person)

Correct: “His ideas are more innovative than hers.” (Comparing ideas to ideas – “hers” implies “her ideas”)

Correct: “His ideas are more innovative than her ideas.”

Implied Parallelism / Ellipsis

Sometimes, words are omitted from a sentence because they are implied, but the structure still needs to be parallel. This is called ellipsis.

Example: “John went to the store, and Mary to the library.”

Here, “went” is implied before “to the library.” The structure “went to X” is parallel for both John and Mary. The GMAT might try to throw in a different structure for Mary’s action, making it unparallel.

Putting It All Together: A GMAT Example

Let’s tackle a GMAT-style sentence to see how these tips work in action.

Original Sentence: “Researchers discovered that the new medication was effective not only in reducing inflammation but also it helped to accelerate healing.”

Okay, first, what are our trigger words? We have “not only…but also.” Immediately, your alarm bells should be ringing for parallelism!

Now, let’s look at what follows each part of the correlative conjunction:

• After “not only”: “reducing inflammation” (a gerund phrase)
• After “but also”: “it helped to accelerate healing” (an independent clause)

Do they match? Absolutely not! A gerund phrase cannot be parallel to an independent clause.

How do we fix it? We need to make the part after “but also” match the gerund phrase after “not only.”

Corrected Version: “Researchers discovered that the new medication was effective not only in reducing inflammation but also in accelerating healing.”

Now, “reducing inflammation” (gerund phrase) is parallel with “accelerating healing” (also a gerund phrase). Much cleaner, much clearer, and perfectly GMAT-compliant!

Your Path to GMAT SC Mastery

Mastering parallelism isn’t just about scoring points on the GMAT; it’s about becoming a better, clearer communicator. And that’s a skill that will serve you well far beyond test day. Remember, the GMAT Sentence Correction section isn’t trying to trick you with obscure rules; it’s testing your ability to write and understand clear, concise, and grammatically sound English.

Parallelism is a fundamental principle of good writing, and once you train your eye and ear to spot it, you’ll find these questions become some of the easiest to conquer. So, keep practicing, keep looking for those trigger words, and keep “drawing the line” to ensure your sentences are perfectly balanced. You’ve got this!

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