Quick Tips for Health Writers: Parallelism in Lists

Let's pretend you need to write an article describing the symptoms of diabetes, which include:

  • feeling thirsty all the time
  • an inability to fight off infections
  • nerve pain in the limbs

Now look at the two sentences below, which each communicate the same idea:

  1. A person with diabetes may experience symptoms like feeling excessively thirsty, difficulty fighting infections, and nerve pain in the limbs. 
  2. A person with diabetes may experience symptoms like excessive thirst, difficulty fighting infections, and nerve pain in the limbs. 

Both sentences say the same thing, but which one is clearer?

Besides being more concise, the second sentence reads more smoothly because it demonstrates better parallelism

What is parallelism? Grammarly defines parallelism as "two or more phrases or clauses in a sentence that have the same grammatical structure." 

When listing items in a sentence, use the same figure of speech for each item in the list.

For example, take a look at the items listed in the first sentence above:

  • feeling excessively thirsty (verb)
  • difficulty fighting infections (noun)
  • nerve pain in the limbs (noun) 

The three parts of speech in the first sentence are verb, noun, and noun. Therefore, the first second is not parallel, because the three items in the list are not all the same part of speech. 

Now let's look at the parts of speech in the second sentence: 

  • excessive thirst (noun)
  • difficulty fighting infections (noun)
  • nerve pain in the limbs (noun)

As you can see, all three items in the second sentence are the same part of speech: noun, noun, and noun. (Don't let the -ing verb fighting throw you off; difficulty is a noun.) 

Here's another example. 

Which sentence shows better parallelism?

1. People with multiple sclerosis may experience tingling, numbness, and fatigue.

2. People with multiple sclerosis may experience tingling, numbness, and to feel fatigued.

In this example, the first sentence demonstrates better parallelism because all three listed items are nouns

The American Psychological Association (APA) also provides a good explanation of parallelism in lists if you'd like to learn more. 

 

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