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Effective Use of Verb Tense in Scientific Writing

Release Date: March 11, 2019
Category: Scientific Writing
Author: Kelsey P., M.S.

In any scientific document, it is the writer’s job to efficiently guide the reader through the information, making the reader’s job easy. To accomplish this goal, proper grammar is critical to make your point clear and avoid misunderstandings. One essential element of grammar is correct verb use. We often find that even the best writers use incorrect verb tenses in scientific writing.

Verbs are words that describe actions within sentences and are crucial for strong and effective writing. The verb tense (primarily past, present, or future) is used by readers to place information relative to time of occurrence. The meaning of a statement can completely change solely based on the verb tense used. For example, the following sentence, which uses present tense, tells the reader that this information is currently accepted as fact. “Antibiotic resistance increases over time.” However, rewriting the sentence in the past tense now implies that this is the result of data collected during a discrete period of time in the past, but may not yet be accepted as a general truth. “Antibiotic resistance increased over time.” Determining the correct verb tense to use can be a challenge in scientific writing, particularly when trying to differentiate previously published results from results that you obtained in your current research. Because different sections of a manuscript are used to deliver different types of information to your reader, specific verb tenses are commonly associated with particular sections of your manuscript, as outlined below.


The present tense is used to describe what is currently accepted as being true because it has been published in the literature. In general, statements that are referenced should be written using present tense.

A poor diet increases the risk of cardiovascular disease… (reference)
The p53 tumor suppressor plays a role in… (reference)

Past tense should be used to describe the methods that were used in previous publications as well as previous hypotheses that have since been disproven.

Mouse tumors were extracted…
The world was thought to be flat…

Materials and Methods:

Past tense should be used to describe work and procedures done for the present study.

We collected tissue samples from…
Transcript levels were measured by RT-PCR…


Past tense should be used to describe the results of work and data that are being presented for the first time in the current document as well as observations and interpretations.

Overall survival was greater in the control group than…
Protein levels increased in…
Our results provided evidence that…

Present tense should be used to describe data that is shown in figures, graphs, and tables. You may therefore have sentences that combine present and past tense verbs.

Figure 4 indicates that mice treated with drug X survived longer than the control mice.


Present tense should be used to interpret results and to discuss the significance and conclusions of the study.

Our data suggest this pathway may be responsible for…

Past tense should be used to summarize the overall findings from the research.

We discovered a new therapeutic target for…

Future tense should be used to convey perspectives and plans.

In future studies, we will examine the effects of…

The above schema provides a brief description of verb tense usage in the different sections of a scientific publication; however, complex sentences can often be tricky because they may require the use of multiple verb tenses to accurately reflect the material presented. For instance, “In 1865, Dr. Joseph Lister postulated that good aseptic technique decreases the spread of infection.” The different verb tenses are necessary in this sentence because postulated refers to the actions Lister took in 1865 and therefore is in past tense, while decreases is in present tense because it denotes a general known fact, which was derived from Lister’s research.

Overall, when deciding which verb tense to use in your writing, focus on the message that you want to convey to the reader in as clear and concise a manner as possible. Remember to pay attention to the scope and condition of the statement. Most importantly, use verb tenses as you ordinarily would in any other communication.

To summarize, use the past tense to describe what was done: the experiments conducted, the results that you obtained, etc. Use the present tense to discuss general truths and previously reported data, to provide insight, and to discuss conclusions. Lastly, use the future tense for perspectives and to discuss future plans.

Keywords: Verb Tense, Verb, Tense, Editing

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