Editing Tip: Avoiding Sentence Fragments

This article discusses how to avoid sentence fragments, which may confuse readers and be considered problematic by journal editors.

A sentence fragment lacks at least one of the three features of a complete sentence: a subject, a verb, and/or a complete thought. As a result, the logical progression of your writing may be unclear, potentially confusing the reader. Although incomplete sentences are regularly used in creative writing and journalism, this sentence structure is too informal for academic writing, with the exception of certain table and figure legends and brief summaries. Fragments lacking one or more of the three components may seem obviously incomplete and are often due to typographical error:

  • Increased five-fold. (fragment lacking subject)
  • The transporter levels. (fragment lacking verb)
  • Such as HeLa and T2 cells. (fragment lacking subject and verb)
  • The transporter levels were. (fragment lacking complete thought)
  • The transporter levels were. Increased five-fold. (fragment possibly due to typo)
  • The transporter levels were increased five-fold in several cell lines, such as HeLa and T2 cells. (complete sentence with subject, verb, and full thought)

Sentence fragments may be more difficult to identify when they consist of a dependent clause that has both a subject and a verb but cannot stand alone. For example:

  • The insulin levels increased. Whereas the glucagon levels decreased.
  • The insulin levels increased. And the glucagon levels decreased.

In both cases, each clause has a subject and a verb (“levels increased” and “levels decreased”). However, in each example, the first sentence is a complete thought, whereas the second sentence is incomplete because it begins with a subordinating (first example) or coordinating (second example) conjunction. These conjunctions are used to link two independent clauses; if only one phrase is associated with a conjunction, the sentence’s meaning may be unclear. Both cases can be addressed by merging the complete and incomplete sentences and adding a comma:

  • The insulin levels increased, whereas the glucagon levels decreased.
  • The insulin levels increased, and the glucagon levels decreased.

The conjunctions now properly link the two independent clauses “The insulin levels increased” and “the glucagon levels decreased.” Alternatively, the fragments could be restructured into complete sentences by using transitions instead of conjunctions:

  • The insulin levels increased. In contrast, the glucagon levels decreased.
  • The insulin levels increased. Additionally, the glucagon levels decreased.

We hope that today’s editing tip will help you to identify and repair sentence fragments in your own writing. As always, please email us at [email protected] with any questions. We wish you the best in your research and writing endeavors!

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

Tips on Writing in English for Researchers [Video Series]

Writing Tips

Tips on Writing in English for Researchers [Video Series]

Sign up to receive this video series about writing in English. Topics include proper subject-verb agreement, using articles, using the word ‘respectively’, and how to... Read More »

Writing Tips

Editing Tip: Avoiding Preposition Overuse

As part of our advice about concise writing, this article shows the problems with too many prepositions in writing and demonstrates how to avoid their... Read More »

Writing Tips

Editing Tip: Split Infinitives

This tip focuses on a pervasive yet unnecessary "rule" of English writing: the ban against splitting infinitives. While splitting infinitives is not often the clearest... Read More »

Stay up to date

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