Parallel Construction - Grammar

AMA Manual of Style - Stacy L. Christiansen, Cheryl Iverson 2020

Parallel Construction
Grammar

Parallel construction is a series of like elements that can be used to build a sentence or emphasize a point. Each element used in a parallel construction has to match the others (eg, verb phrases, clauses, sentences).2

7.9.1 Correlative Conjunctions.

Parallelism may rely on accepted cues (either/or, neither/nor, not only/but also, both/and). All elements of the parallelism that appear on one side of the coordinating conjunction should match corresponding elements on the other side.

Avoid:

The compleat physician has not only mastered the science of medicine but also its art.

Correct:

The compleat physician has mastered not only the science of medicine but also its art.

Better:

The compleat physician has mastered both the science and the art of medicine.

Avoid:

Poor drug efficacy may be caused by either lack of absorption or by increased clearance.

Correct:

Poor drug efficacy may be caused either by lack of absorption or by increased clearance.

Also correct:

Poor drug efficacy may be caused by either lack of absorption or increased clearance.

Avoid:

Three patients did not either take their medication or took it incorrectly.

Correct:

Three patients either did not take their medication or took it incorrectly.

Note: Either/or is used with only 2 comparators (use with more than 2 items is considered nonstandard).

Incorrect:

This medication can be taken with either water, milk, or juice.

Correct:

This medication can be taken with water, milk, or juice.

7.9.2 Elliptical Comparisons.

The conjunction than often introduces an abridged expression (eg, “You are younger than I [am young].)” Correct placement of than is important to avoid ambiguity.

Unclear:

Women are more likely to take vitamins than men. [Are women more likely to consume vitamins than men are, or are women more likely to consume vitamins than they are to consume men?]

Better:

Women are more likely than men to take vitamins.

7.9.3 In Series or Comparisons.

Parallel construction may also present a series or make comparisons. In these usages, the elements of the series or of the comparison should be parallel structures (eg, nouns with nouns, prepositional phrases with prepositional phrases). (Note that it is not necessary to repeat auxiliary verbs in a correctly built parallel construction.)

Avoid:

Surgery, radiation therapy, and starting chemotherapy are possible therapeutic approaches.

Correct:

Surgery, radiation therapy, and chemotherapy are possible therapeutic approaches.

Avoid:

When an operation is designed to improve function rather than removal of an organ, surgical technique dictates outcome.

Correct:

When an operation is designed to improve the function of an organ rather than to remove the organ, surgical technique dictates outcome.

Avoid:

The new approach would have improved patient outcomes, would have shortened wait times, and would have saved money.

Better:

The new approach would have improved patient outcomes, shortened wait times, and saved money.

Note: Avoid the use of nor when the first negative is expressed by not or no.

There were no negative effects on self-reported health status or [not nor] in measured clinical values.

7.9.4 Lists.

Parallel construction is also important in lists, whether run in or set off by bullets or some other device (see 8.2.2, Semicolon, and 19.8, Enumerations).

After completing this CME exercise, readers should be able to

■identify the causal mechanism of the disease,

■describe the most common symptoms, and

■understand the limitations of pharmacologic treatment.