As proofreaders/editors, we often talk about parallelism in writing, but what is this, and how do we avoid and correct faulty parallelism? This guide will explain.
You’ll recall from school math classes that parallel lines travel in the same direction. Well, in much the same way, parallelism in writing is about ensuring that the phrases or clauses in a sentence agree with each other in terms of their grammatical structure. In other words, they have a parallel construction. If the elements of a sentence are parallel, it improves readability and makes the text easier to process.
Before we get into specifics, let’s start with a general example to illustrate the point.
While ‘I like reading’, ‘I like to listen to music’ and ‘I like to cook’ are all perfectly valid grammatically, this sentence doesn’t read well because we have one gerund (-ing form) and two infinitives—the items aren’t parallel. We could improve this markedly by choosing one form and sticking to it:
(Note, the ‘to’ does not need to be repeated.)
When do we need to ensure parallelism?
There are various situations in which parallelism is needed in a sentence, so let’s look at some of these and at examples of how parallelism can be faulty.
Coordinating conjunctions and correlative conjunctions
When coordinating conjunctions (for, and, nor, but, or, yet, so) or correlative conjunctions (those such as either… or, neither… nor, both… and, not… but rather, and whether…or) separate words, phrases or clauses, we need parallelism.
The faulty parallelism in the above arises from the combination of a noun phrase (‘good morals’) and a verb phrase (‘to be respected by the public’).
Once again, if we choose one form and stick to it, the sentence will be improved.
In this example, our problem is the combination of a noun phrase (an enthusiastic philosopher) and an adjective phrase (skilled in science).
Once again, if we’re consistent, we’ll solve the faulty parallelism problem:
Items in a series
When we present items in a list or series, we should ensure that they are all parallel (all nouns, all adjectives, all gerunds, all infinitives, etc.)
The rogue noun phrase at the end has resulted in faulty parallelism with the first two verbs.
To correct this:
One other place you are likely to encounter issues with parallelism is in bullet point lists. Aside from the kinds of considerations given above, there are some other things to think about here when it comes to parallelism.
If the items in a bullet point list complete an introductory sentence with a colon, be sure that all the items in the list actually work with the grammar of the introduction. For example:
The report established that the organization had:
- ignored warnings
- breached guidelines
- disregarded worker safety
- didn’t accept responsibility.
While the first three items follow on from the introductory sentence, the last item does not. For parallelism, this could be changed to ‘failed to accept responsibility’, ‘refused to accept responsibility’ or ‘not accepted responsibility’. When you see this kind of list, try reading the introductory sentence before each bullet point; that will make it easier to spot problems.
Another thing to look out for is the use of incomplete and complete sentences in bullet items. For parallelism, either all the items in the list should be incomplete sentences, or they should all be complete sentences. For example:
This has allowed us to make a number of recommendations.
- Levels of consumption should be reduced.
- Global carbon emissions must be brought into line with targets.
- More trees.
- Cleaner air.
While the first two points are complete sentences, the last two are not, so this list is not parallel. In cases like this, we might choose to make the appropriate changes ourselves, or raise the issue with the customer so that they can choose how they prefer the list to be presented (it may not be possible to extrapolate from a fragment what the full sentence should be).