Welcome to the parallel universe

Parallelism--a word adopted from the field of of mathematics by teachers of writing--is an excellent principle to ensure correctness, clearness, and effectiveness of your sentences. When two or more ideas in a sentence are related and serve a similar purpose, they should be phrased in the same grammatical form. Many students have a hard time understanding parallel structure.

For example:

Unclear: She liked to sing and playing golf.
Clear: She liked to sing and to play golf. OR She liked singing and playing golf.

Unclear: What do rich suburban kids know about crime, those who are hungry, and poverty?
Clear: What do rich suburban kids know about crime, hunger, and poverty? OR What do rich suburban kids know about people who are hungry, poor, and victims of crime?

As you can see, faulty parallelism disrupts the balance of a sentence. It interrupts the sentence's smooth flow, causing the reader to momentarily hesitate as he or she tries to process the information and make sense of what you're attempting to express. So, always remember to use parallel elements to express parallel ideas. Balance nouns with nouns, prepositional phrases with prepositional phrases, main clauses with main clauses, and so forth.

Here are some examples:

Parallel words and phrases
Jackson is slow but thorough.
Life is both a mystery and an adventure.

Parallel clauses
My favorite things to do as a kid were playing video games, eating caramel popcorn, and going to soccer games.
Both at work and at home Alec's only thoughts were about making money and having fun.
I was panicked when I arrived late on campus and when I found that no statistics courses were available.
Professor Williams likes to read the Classics and to go hang-gliding.

Parallel sentences
Tom Thumb was one of the smallest people in the circus world. Andre the Giant Killer was one of the biggest people in the wrestling world.
The Hummer is one of the least fuel-efficient vehicles ever made. The Prius is one of the most fuel-efficient vehicles ever made.

Finally, for another example of parallel sentence structure, go back to the first sentence of this blog. Can you see how the words correctness, clearness, and effectiveness are parallel and how they make the sentence easier to comprehend? If you do, then you're starting to understand the the value of parallelism in the writing world.