Parallelism and Faulty Comparisons

An explanation of parallelism in English grammar with examples and other resources

The Principle of Parallelism

Parallelism is a generally recognized principle of good writing: when you write a complex sentence, you should try to make the different parts of the sentence match each other in structure. There should be a structural consistency throughout the sentence. That consistency makes the sentence smoother, more natural, and easier to understand.

Parallelism: What & Why

Grammatical parallelism occurs when separate elements in a sentence, such as phrases or clauses, have the same structure or follow the same pattern. Parallelism makes information easier to read and process.

Parallelism in Lists

Perhaps the most obvious situation in which parallelism comes up is in writing a list or series. As in the sentence above, which features a list of comparative adjectives (smoother, more natural, easier), items in a series should all be in the same form.

Batman rushed to put on his Bat-cummerbund, Bat-bowtie, and pin on his Bat-lapel pin before he left to pick up Aquababe.

The list in this sentence begins as a list of items, but at the end of the list another verb is awkwardly inserted into the list, making it unparallel. However you write the sentence, make sure that it has a parallel structure.  The simplest way to do so is to write the list as a series of nouns:

Batman rushed to put on his Bat-cummerbund, Bat-bowtie, and Bat-lapel pin before he left to pick up Aquababe.

If you need to express more subtle distinctions, restructure the sentence to avoid an unparallel list:

Batman rushed to put on his Bat-cummerbund and Bat-bowtie and to pin on his Bat-lapel pin before he left to pick up Aquababe.

When a list involves verbs or verb forms, make sure they are all in the same form:

Before he could leave for the Superfriends Prom, he still had a few things to do: grab Aquababe’s corsage, turn off the lights in the Bat-cave, and slipping slip a sedative into Alfred’s drink.

Parallelism with Correlative Conjunctions

A number of frequently used expressions, such as “not onlybut also…” and “eitheror…,” require a parallel construction. Be sure that you position these conjunctions carefully within the sentence:

Batman was sure he was going to not only look cooler than Aquadork but also Superman, who thought he was so fly that he could get away with going to prom in his Cheetos-stained uniform.

Whatever kind of word appears after the first conjunction should also appear after the second conjunction. Usually, it’s best to avoid repeating words unnecessarily. The words that precede the first conjunction are also understood to apply to whatever comes after the second conjunction, so they don’t have to be repeated:

Batman was sure he was going to look cooler than not only Aquadork but also Superman.

The distributive property in math says (to put it in terms easily comparable to grammar) that an element that precedes an expression in parentheses is multiplied by each element of that expression:

x(y + z) = xy + xz

The same rule applies to these kinds of parallel constructions:

look cooler than (not only Aquadork but also Superman) = look cooler than Aquadork and look cooler than Superman

This rule allows us to simplify the sentence and avoid highly repetitive wording.

Correlative Conjunctions

Correlative conjunctions are conjunctions that work together in pairs to introduce multiple elements such as nouns or adjectives and relate them to each other. Correlative conjunctions create a parallel structure and imply that the elements they introduce should be parallel in form and style.


  • either…or…
  • neither…nor…
  • both…and…
  • not only…but also…
  • not…but…
  • at once…and…

Parallelism in Comparisons

You’ve probably heard the expression “apples and oranges,” which is used to suggest that two things are so different that it doesn’t make sense to compare them directly. In Standard English, the rules about making comparisons are quite strict; the wording of the sentence must suggest the comparison very precisely.

Batgirl, Aquadork’s back-up date, was jealous of Aquababe because Aquababe’s dress looked a lot hotter than Batgirl Batgirl’s dress(or just “than Batgirl’s”)

The sentence above is intended to express a comparison of one person’s dress with another person’s dress, but the wording is unparallel and thus illogical. (To compare one person’s dress to another person is figuratively like comparing an apple to an orange when you really mean to compare two apples.) This kind of inconsistency is called a faulty comparison.

Although Aquadork wanted to win Aquababe back, Batman’s dance moves were smoother than Aquadork Aquadork’s.

In more formal or complex comparisons, the pronouns that (for singular nouns) and those (for plural nouns) are used to avoid repetitive wording:

The dance moves that Batman busted out were smoother than the dance moves that Aquadork tried to do. (too repetitive)

The dance moves that Batman busted out were smoother than those that Aquadork tried to do.

In addition, make sure you use the idiomatically correct wording when expressing comparisons. Than is used for expressing differences using comparative adjectives (e.g. hotter) and the expression “as…as…” is used for expressing similarity. According to traditional grammar authorities, “soas…” is the correct expression to use for negative comparisons of this kind (comparisons involving words such as no, not, and never). However, this rule is rarely taught or followed in contemporary English.

Batman looked just as hot than as Aquababe, and they made all of the other Superfriends look like chumps.

Batgirl’s nightly moontans just weren’t as so effective as Aquababe’s suntans.

Another kind of faulty comparison involves an error in logic. When comparing one thing to other things in the group it belongs to, be sure not to suggest a comparison of the thing to itself:

Robin (or “Batman’s Brat,” as Superman liked to call him) was dorkier than any of the Superfriends, and after his infamous “Bieber incident” at the prom, Superman argued that his membership should be revoked.

Since Robin is one of the Superfriends (at least for now), if you say that he is “dorkier than any of the Superfriends” you’re logically implying that he is dorkier than himself.  The solution to this problem is simple:

Robin was dorkier than any of the other Superfriends.

Now Robin himself is excluded from the group he is being compared to, and the comparison is logical.


Faulty comparison: An illogical, “apples and oranges” comparison of one thing to something fundamentally different that occurs when the wording of the comparison is not strictly parallel

Each of these words and expressions implies a comparison.  Remember to make your comparisons logical and parallel when using them:

  • as…as…
  • less…than…
  • like
  • more…than…
  • [comparative adjective/adverb]…than…
  • not so…as…
  • resemble(s)
  • (the) same as
  • similar to
  • unlike

Omitted Words in Parallel Structures

In parallel structures, the presence of certain words is implied. In such cases, we often omit them for the sake of conciseness instead of repeating them. (See the discussion of parallelism with correlative conjunctions above as well.)

Batman thought he could teach Aquadork how to krump, how to pop and lock, and how to clown walk, but he was horribly, horribly wrong.

Because of its parallel structure, this sentence can be shortened; “how to” does not have to be repeated because it is understood to apply to each item in the series (again, like the distributive property):

Batman thought he could teach Aquadork how to krump, pop and lock, and clown walk, but he was horribly, horribly wrong.

In parallel compound sentences joined with a semicolon, the verb in the second clause can be replaced with a comma:

Robin won the Worst Imitation of Justin Timberlake Award; Superman, the Cheesiest Attire Award.

= Robin won the Worst Imitation of Justin Timberlake Award; Superman won the Cheesiest Attire Award.

Remember that the second part of the sentence is still considered an independent clause, so a semicolon is needed to join it with the first part.

As mentioned in my handout “Verb Errors on the SAT,” this principle also applies to a number of other situations involving verbs. Refer to that handout for more examples.

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© 2008 C. Brantley Collins, Jr.