Read this article about when to use the present simple, past simple, and present perfect verb tenses. A common mistake in writing is to shift verb tenses, such as by writing in the present tense and then shifting to the past tense. To avoid this, try to choose the appropriate verb tense and use it consistently throughout your writing.
What this Handout is About
These three verb tenses account for approximately 80% of the verb tense use in academic writing. This handout will help you understand how present simple, past simple, and present perfect verb tenses are used in academic writing.
Present Simple Tense
The present simple tense is the basic tense of most academic writing. Use this as your first choice unless you have a good reason to use another tense. Specifically, the present simple is used:
- To frame your paper: in your introduction, the present simple tense describes what we already know about the topic; in the conclusion, it says what we now know about the topic and what further research is still needed.
- To make general statements, conclusions, or interpretations about previous research or data, focusing on what is known now (The data suggest … The research shows …).
- To cite a previous study or finding without mentioning the researcher in the sentence:
The dinoflagellate's TFVCs require an unidentified substance in fresh fish excreta (Environmental Science) 
- To introduce evidence or support in the structure:
There is evidence that …
- To show strong agreement with a conclusion or theory from a previous paper (Smith suggests that …), but not specific findings or data (use the past simple)
Past Simple Tense
Past simple tense is used for two main functions in most academic fields:
- To introduce other people's research into your text when you are describing a specific study, usually carried out by named researcher. The research often provides an example that supports a general statement or a finding in your research. Although it is possible to use the past tense to distance yourself from a study's findings, this appears to be rare, at least in scientific writing.
…customers obviously want to be treated at least as well on fishing vessels as they are by other recreation businesses. [General claim]
De Young (1987) found the quality of service to be more important than catching fish in attracting repeat customers. [Specific supporting evidence] (Marine Science)
- To describe the methods and data of your completed experiment. However, look at examples of the Methods and Results sections in journals in your fields to check that this is good advice for you to follow. In many fields, the passive voice is most usual in methods sections, although the active voice may be possible.
We conducted a secondary data analysis … (Public Health)
Descriptional statistical tests and t-student test were used for statistical analysis. (Medicine)
The control group of students took the course previously … (Education)
Present Perfect Tense
The present perfect is mostly used for referring to previous research in the field or to your own previous findings. Since the present perfect is a present tense, it implies that the result is still true and relevant today.
- The subject of active present perfect verbs is often general: Researchers have found, Studies have suggested. The present simple could also be used here, but the present perfect focuses more on what has been done than on what is known to be true now (present simple). In the following example, there are two opposite findings, so neither is the accepted state of knowledge:
Some studies have shown that girls have significantly higher fears than boys after trauma (Pfefferbaum et al., 1999; Pine &; Cohen, 2002; Shaw, 2003). Other studies have found no gender differences (Rahav &; Ronen, 1994). (Psychology)
- A new topic can be introduced with this structure:
There have been several investigations into …
- The present perfect forms a connection between the past (previous research) and the present (your study). So, you say what has been found and then how you will contribute to the field. This is also useful when you want to point out a gap in the existing research.
More recently, advances have been made using computational hydrodynamics to study the evolution of SNRs in multi-dimensions …(citation) … [previous research]
However, a similar problem exists in the study of SNR dynamics. [gap] (Astrophysics)
- The passive voice is common in the present perfect tense to describe previous findings without referring directly to the original paper: … has been studied; it has been observed that … You should usually provide citations in parentheses or a footnote. The passive voice allows you to move the subject of your research into a place in the sentence where it will have more focus.
- You can also use the present perfect to tell the history of your idea (what has created it?), describe the results of your research (we have developed a new …), or to draw conclusions (this has led us to conclude that …).
 Example reproduced from Penrose & Katz, 2004, p. 330
 According to Hawes and Thomas, 1997
Biber, Douglas et al. Longman Grammar of Spoken and Written English. Longman, 1999.
Hawes, Thomas, and Sarah Thomas. "Tense Choices in Citations". Research into the Teaching of English, 31 (1997): 393-414.
Hinkel, Eli. Teaching Academic ESL Writing. Lawrence Erlbaum, 2004.
Penrose, Ann, and Steven Katz. Writing in the Sciences: Exploring the Conventions of Scientific Discourse. 2nd ed. Pearson Longman, 2004.
Swales, John, and Christine B. Feak. Academic Writing for Graduate Students: Essential Tasks and Skills. 2nd ed. University of Michigan Press, 2004.
Source: The University of North Carolina at Chapel Hill Writing Center, https://writingcenter.unc.edu/tips-and-tools/verb-tenses/
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.