Teaching Tip: Teach Students to Write Readable Sentences

Do your students struggle to write about technical topics in clear language? The Northwestern University Collaborative Learning and Integrated Mentoring in the Biosciences (CLIMB) initiative created a set of video tutorials on professional writing in STEM (Science, Technology, Engineering, and Math). Although the video is directed at a STEM audience and uses writing examples drawn from STEM texts, the five principles will improve writing clarity in all disciplines.

The Five Principles for Readable Sentences video describes strategies authors can use to write clearly about complex technical topics. The video defines each principle and illustrates how the principle can be used to edit writing and improve clarity. The video presents examples of scientific texts that violate each principle, followed by an edited text that shows how clarity improves when writers apply the principle. The video is short enough (less than 15 minutes) to assign as a short tutorial.

Five principles for clear scientific writing described in the Five Principles video:

  • Given before new. Begin sentences with information we expect the reader to already know (given information) followed by information that is new. This strategy reflects a communication principle known as common ground, which describes how speakers develop common reference points and use shared knowledge to support meaningful conversations (Clark & Wilkes-Gibbs, 1986; Haviland & Clark, 1974). A sentence should begin with established or old information, which creates a context that helps readers understand the new information. When writing a paragraph, discuss old information before introducing new information. Create clear connections between the new concepts and the old information you discussed.
  • Light to heavy. Structure sentences to move the reader from light, easy-to-understand information to more difficult or more complex (heavy) information. Begin sentences with easy concepts that establish context for understanding the complex concepts you plan to introduce later.
  • Transitions. Transition words improve the flow of language because they help readers follow the logical structure of your argument. Choose transition words carefully. Transition words serve as signposts for readers. They should clearly indicate how the ideas they connect are related. Transition words may describe sequences, connect causes with effects, or signal presentation of an example, making a comparison, drawing a contrast, reaching a conclusion, or making a summary (for example identifies the new information as supporting evidence; however implies that the new information will describe a contrast or an exception to the old information).
  • Echo words. Consistent word use improves readability. Echo words appear repeatedly and always refer to the same thing. Some writing guides suggest that we vary word choice to add interest, but this strategy can backfire in technical writing. Technical writers choose different words to refer to similar but distinct concepts. Their intent is to use a different word for each concept to highlight the differences in meaning. An author who creates variety by using different words for the same concept introduces confusion. The reader must work to figure out if the author introduced a new word to add variety and interest or if the new word describes a new concept. In technical writing, if you intend to refer to the same concept multiple times, be consistent and use the same word each time you write about the concept.
  • Write in the active voice. Express actions as verbs in sentences using the active voice. When we write sentences in the passive voice, the text is more difficult to understand. The passive voice forces us to turn the verb for an action into a noun (nominalizations). For example, we can use a verb (introduce) and write in the active voice (He introduced a concept in the first class) or we can turn the verb into a noun (introduction) and write the sentence in the passive voice (Introduction of a concept occurred in the first class). The second sentence is more difficult to understand and less interesting to read.


Clark, H. H., & Wilkes-Gibbs, D. (1986). Referring as a collaborative process. Cognition, 22, 1-39.

CLIMB (Collaborative Learning and Integrated Mentoring in the Biosciences). Five Principles for Readable Sentences [video] Located on the Written Communication resource page. Northwestern University. [Accessed at:]

Haviland, S. E., & Clark, H. H. (1974). What’s new? Acquiring new information as a process in comprehension. Journal of Verbal Learning and Verbal Behavior, 13, 512-521.

Submitted by:
Claudia J. Stanny, Ph.D., Director
Center for University Teaching, Learning, and Assessment
University of West Florida
Pensacola, FL
(850) 473-7435