In general, when writing an abstract, you should use the simple present tense when stating facts and explaining the implications of your results. Use the simple past tense when describing your methodology and specific findings from your study. Either of these two tenses can be used when writing about the purpose of your study. Finally, you can use the present perfect tense or the present perfect progressive tense when explaining the background or rationale of your study.
Determining which tense to use when writing an abstract is not always straightforward. For example, even though your research was carried out in the past, some aspects of your work need to be referred to using the present tense. The purpose of this article is to teach you when to use which of four different tenses (i.e., the simple present tense, the simple past tense, the present perfect tense, and the present perfect progressive tense) when writing an abstract for a research paper.
When to Use the Simple Present Tense
The simple present tense of a verb is used for two purposes. The first is to describe something that is happening right now (e.g., “I see a bird”). The second is to explain a habitual action — that is, an action that one performs regularly, though they might not be doing it at this very moment (e.g., “I sleep for eight hours every night”).
When writing an abstract, the simple present tense is used for three main purposes: (i) to state facts, (ii) to explain the implications of your findings, and (iii) to mention the aim of your research (the simple past tense can also be used for this last purpose).
When stating facts
You will usually use the simple present tense to refer to facts since they will be just as true at the time of writing as they were when your study was being carried out. Exceptions arise if a fact is explicitly linked to some point in the past.
Examples
Indoor nighttime light exposure influences sleep and circadian rhythms.
Here, the author is making a general statement based on previous research in their field. Broad statements like this one are based on very extensive research, and so researchers assume such statements to be factual. Thus, they should be mentioned in the simple present tense.
China, whose estimated population was 1,433,783,686 at the end of 2019, is the most populated country in the world.
The author shifts from the past tense to the present tense because the first fact is explicitly linked to a point in the past (the end of 2019). Because populations change by the second, the author cannot assume the figure given is still accurate, and so they refer to this figure using the past tense. Differently, the author can reasonably assume that China still has the world’s largest population at the time of writing. Thus, this statement is written in the present tense.
When explaining the implications of your findings
You should discuss the implications of your study in the present tense. Although your research was conducted in the past, its implications remain relevant in the present.
To give an example, although the United States Declaration of Independence was adopted centuries ago, it is still in effect today, and so general statements about it are usually written in the present tense (e.g., “The US Declaration of Independence describes principles through which the United States Constitution should be interpreted”).
In the same way, because your research is still relevant at the time of writing, general statements about its implications should be written using the present tense as well.
Example
Results revealed that adolescents with depression experience difficulties with sleep quality.
Here, the author starts by using the past tense because the results were produced in the past. However, because the implication of the results remains true at the time of writing, the author switches to the present tense. While it would be acceptable for the author to use the present tense of “reveal” in this sentence, it would not be okay for them to use the past tense of “experience” unless they were referring to a specific result from their study.
When describing the aim of your study
For the same reason that you should write about your study’s implications in the present tense, you can also write about the purpose of your study in the present tense. However, this rule is flexible, and it is very common for authors to write about such information in the past tense.
Examples
In this study, we explore the link between the homeostatic regulation of neuronal excitability and sleep behavior in the circadian circuit.
In this study, we explored the link between the homeostatic regulation of neuronal excitability and sleep behavior in the circadian circuit.
Both of these examples are perfectly fine. You should check your journal’s guidelines or papers that have been published in the journal to determine which tense you should use for these kinds of sentences.
When to Use the Simple Past Tense
The simple past tense of a verb is used when discussing something that happened in the past and is not still occurring (e.g., “I ate cereal this morning”).
As seen in the previous section, the simple past tense can be used to explain the purpose of your study. It should also be used when describing specific aspects of your research, such as its method and findings.
When describing your methodology and findings
Because your method has been completed at the time of writing, you should write about your method in the past tense. Similarly, because you have finished analyzing your data to obtain your findings, they should also be expressed in the past tense.
Examples
Thirty-four older people meeting DSM-IV criteria for lifetime major depression and 30 healthy controls were recruited.
Like any aspect related to methodology, the recruiting process started and finished well before the time of writing. As such, it is standard for this information to be described using the past tense.
Individuals with depression had longer sleep latency and latency to rapid eye movement sleep than controls.
Here, the author is referring to their study’s participants (this is clear because “controls” are mentioned). Since the participants have finished taking part in the study at the time of writing, this result is described in the past tense.
Results revealed that the adolescents with depression who participated in our study experienced difficulties with sleep quality.
This example is very similar to an example given in the previous section of this article (“Results revealed that adolescents with depression experience difficulties with sleep quality”). In the previous example, the present tense of “experience” was used because the author was making a broad statement about adolescents in general. Conversely, in the current example, the author is mentioning a specific result from their study. Because the study is over, the author used the past tense.
When to Use the Present Perfect (Progressive) Tense
When writing an abstract, you might sometimes need to use the present perfect tense (e.g., “Research on this topic has increased“) or the present perfect progressive tense (e.g., “Research on this topic has been increasing“) of verbs. These verb tenses are used to describe an action or situation that began in the past and that is still occurring in the present. The former tends to be used when the starting point of the action is vague, whereas the latter is often used when the starting point is mentioned (this rule is flexible, though).
A further difference between the two is that the present perfect tense — but not the present perfect progressive tense — can also be used to describe an action or situation that has been completed at some non-specific time in the past (e.g., “I have finished writing my paper”).
While these verb tenses are not used as often in abstracts as the tenses discussed previously (sometimes, they are not used at all), you can use them to describe situations or events related to the background of your study.
When describing the background of your study
In abstracts, the present perfect and present perfect progressive tenses are most commonly used to describe background aspects of the research. For example, you might mention the specific situation that motivated you to conduct your research or the gap in the literature that you want to address. Such things tend to be ongoing problems (i.e., they were created in the past and have not been resolved yet). Therefore, they should be written about using the appropriate tense.
Examples
Researchers have investigated the association between several consecutive long work shifts and risk factors for developing CVD.
This sentence communicates that researchers began investigating the described association sometime in the past and that they continue to do so at the time of writing. Because the starting point is not given, the use of the present perfect tense is preferred. However, the present perfect progressive tense would be acceptable.
Since Smith’s (2017) ground-breaking study on the subject, researchers have been investigating the association between several consecutive long work shifts and risk factors for developing CVD.
This time, because a specific starting point is given, the present perfect progressive tense is preferred over the present perfect tense. Again, though, both tenses are acceptable.
In response to the demand for ‘24/7’ service availability, shift work has become common.
Unlike the previous examples, only one of the two tenses is acceptable for this example. This sentence must be written in the present perfect tense because the situation described has already happened. Only if this paper had been written a few decades ago, while this transition in society was still taking place, would the author have been correct to use the present perfect progressive tense.
Using Different Tenses in Practice
I now present the abstract of an article that was recently published in Psychological Bulletin. Below the example, I explain why the author used a specific tense for each sentence.
(1) Targeted memory reactivation (TMR) is a methodology employed to manipulate memory processing during sleep. (2) TMR studies have great potential to advance our understanding of sleep-based memory consolidation and corresponding neural mechanisms. (3) Research making use of TMR has developed rapidly, with over 70 articles published in the last decade, yet no quantitative analysis has evaluated the overall effects. (4) Here we present the first meta-analysis of sleep TMR, compiled from 91 experiments with 212 effect sizes. (5) Based on multilevel modeling, overall sleep TMR was highly effective, with a significant effect for two stages of non-rapid-eye-movement (NREM) sleep. (6) In contrast, TMR was not effective during REM sleep nor during wakefulness in the present analyses. (7) Several analysis strategies were used to address the potential relevance of publication bias. (8) Additional analyses showed that TMR improved memory across multiple domains, including declarative memory and skill acquisition. (9) Given that TMR can reinforce many types of memory, it could be useful for various educational and clinical applications. (10) Overall, the present meta-analysis provides substantial support for the notion that TMR can influence memory storage during NREM sleep.
The author is stating facts in Sentences (1) and (2) and, therefore, has used the simple present tense.
The author uses the present perfect tense twice while describing the rationale of their study in Sentence (3). Whereas the author could have chosen to use the present perfect progressive tense in the first case, they had no option in the second case — the present perfect progressive tense usually sounds unnatural when used for negative statements.
Then, the author briefly explains the aim of the study in Sentence (4), using the simple present tense (the simple past tense also would have been acceptable).
Sentences (5), (6), and (8) describe specific results from the current study, while Sentence (7) is related to the methodology. As such, Sentences (5)-(8) are written in the simple past tense.
Finally, because Sentences (9) and (10) mention the implications of the present study, they are written in the simple present tense.