News, tips, and resources from the academic publishing experts at AJE

Editing Tip: Singular and Plural Verbs with Measured Quantities

Learn how to use measurements such as time, percent, and various units in relation to verbs in a sentence.

Scientific writing often involves measurements and units such as milliliters (ml) or microns (µm). Measured quantities involving these units are often found in tables or parentheses, and not always within the text of a sentence. However, when a measured amount (e.g., 500 ml) is the subject of a sentence or clause, the choice of verb to agree with the measurement presents a unique situation in academic English writing.

When a measurement is being described in a sentence, that quantity takes a singular verb form. In such cases, the entire quantity is thought of as a single entity that should be considered together, not separately. See the following examples, in which the entire sample was added or tested at a single time:

  • In total, 10 g of tissue was tested. (NOT: 10 g of tissue were tested)
  • Five milliliters of solvent was added to the mixture. (NOT: Five milliliters were added)

A plural verb is appropriate when items should be considered individually (e.g., "Ten mice underwent surgery"). In this example, surgery was performed on ten mice, one at a time, so a plural verb is correct.

Last, percentages can fall into either category: a collection that should be treated as a single entity (singular verb) or a group of individuals that should be treated separately (plural verb). For example:

  • In total, 30% of the study duration was spent on the follow-up testing.
    Here, the duration (an amount of time) can be thought of as a single block, not as countable units.
  • Twenty percent of the participants were assigned to the experimental condition.
    In this example, each participant was assigned to experimental or control conditions, and the number of individual patients assigned to the experimental group constituted 20% of the total patient sample.

English grammar is sometimes tricky, and academic writing often adds new confusing conventions. We hope that this post has helped clear up the use of singular or plural verbs with measured quantities. As always, please email us if you have questions.

Share with your colleagues

Share your work as a preprint and help move science forward

We invite you to share your research with the community by posting it online as a preprint. Our sister company, Research Square, is a trusted preprint platform that lets you get credit for your unpublished research early, increase your citations, and get feedback from the community.

Related Articles

Know Your Verbs

Editing Tip: Common Prepositional Verbs

Prepositional verbs, or verbs that are paired with prepositions, can be challenging for any writer, especially because there are few consistent rules about preposition use... Read More »

Know Your Verbs

Subject-Verb Agreement Across Prepositional Phrases

How to make sure your subject and verb agree even if there are intervening words or phrases. Read More »

Know Your Verbs

Powerful Verbs in Your Academic and Scientific Writing

Learn how to strengthen your research manuscript with strong, meaningful verbs. Read More »

Stay up to date

Sign up for early access to AJE Scholar articles, discounts on AJE services, and more