What is Parallel Structure?

Parallel structure is often a necessary component of clear, balanced sentences. It is achieved whenever two or more words, phrases, or clauses in a sentence have the same grammatical pattern. Parallelism promotes readability and grants equal importance to the various components within the sentence.

A lack of parallelism can occur in a variety of ways, usually resulting in sentences that are awkward or confusing. The following is an example of a sentence that lacks parallel structure:

• In their legal writings, lawyers should strive to be accurate, concise, and to persuade their audience.

That sentence includes a series in which the first two elements follow the words “to be,” and the last element does not. An easy way to check for parallel structure in such a case is to break the series into individual sentences. For instance:

• In their legal writings, lawyers should strive to be accurate.
• In their legal writings, lawyers should strive to be concise.
• In their legal writings, lawyers should strive to be to persuade their audience.

That last one, obviously, does not work. However, the sentence can easily be rewritten as follows:

• In their legal writings, lawyers should strive to be accurate, concise, and persuasive.

In the rewritten version, all elements of the series have the same form, function, and weight.

Here’s another example of a sentence lacking parallel structure:

• The judge recommended the manual’s comprehensive subject matter and using its forms.

In the sentence above, the judge is recommending two things about a manual: its subject matter (a noun) and using (a verb) its forms. In a stronger (i.e., parallel) sentence, the two elements would match. For instance:

• The judge recommended the manual for its comprehensive subject matter and useful forms.

Or--

• The judge recommended reviewing the manual’s comprehensive subject matter and using its forms.

In a sentence with prepositional phrases, parallel structure would involve including the preposition with each element—unless every element shares the same preposition. The following sentence, therefore, lacks parallel structure:

• The attorney looked for additional information in the bar’s CLE database, the firm’s library, and on an expert’s website.

The correct way to write the sentence would be:

• The attorney looked for additional information in the bar’s CLE database, in the firm’s library, and on an expert’s website.

However, what if you were to replace “on an expert’s website” with “in the county’s records”? In that case, you can delete “in” before the last two elements, since the preposition “in” applies to all of the elements in the series:

• The attorney looked for additional information in the bar’s CLE database, the firm’s library, and the county’s records.

There are many ways to violate the rules of parallel sentence structure, although the examples discussed above illustrate a few of the more common ones. Sometimes a sentence that lacks parallel structure can be easy to spot—and sometimes the error is more subtle. Crafting sentences with proper parallel structure, though, is worth the time and effort. It ensures that your writing is clear, balanced, and professional.