The Introduction and Literature Review sections of your paper must include background to your research. Authors who publish successfully and publish often know how to use verb tense effectively as a powerful persuasive tool.
Let’s take the example below, whose two verbs are a standard format for reporting findings. There are two verbs: the first verb has a reporting function (“to show”, “to demonstrate”, “to suggest”, etc.), while the second verb relates to the contents of the sentence. We will look at present tense and past tense.
Which verb tense should we insert?
Gupta et al. (2012) show // showed that lower vitamin D levels in children with severe, therapy-resistant asthma (STRA) are // were associated with worse asthma control and lung function.
First verb – show//showed
Using past tense for the first verb is uncontroversial and recommended. It is appropriate because the research was conducted in the past.
Correct & Natural: Gupta et al. (2012) showed that…
Using the present tense is not forbidden: it suggests “the study, which is published and available to read at present, says…”. However, it can sound affected: use with caution.
Correct & Slightly Strange: Gupta et al. (2012) show that…
Second verb – are//were associated
Using past tense localizes the findings to the time of the experiment, while using present tense suggests the findings are true and applicable even now. You can use both, but the present tense sounds stronger. Using the present tense for the second verb will be perceived as a strong assertion of the findings!
Correct: …lower vitamin D levels in children with STRA were associated with worse asthma control and lung function.
[This was a finding of Gupta et al.’s study in the past.]
Correct and stronger assertion: …lower vitamin D levels in children with STRA are associated with worse asthma control and lung function.
[This finding of Gupta et al. holds true even today.]
You can even use the relative weakness of the past tense to implicitly dismiss past findings.
Smith et al. (2008) found that vitamin D levels had no relation with asthma severity or recurrence. However, Gupta et al. (2012) reported a contradictory finding, saying that lower vitamin D levels in children with STRA are associated with worse asthma control and lung function.
[Smith et al. said there was no relation, but we believe that, in reality, there is a relation.]
To report findings most strongly, you can omit the first part (“Gupta et al. showed…”) entirely! The readers will know you are reporting a finding because of the presence of a citation.
Lower vitamin D levels in children with STRA are associated with worse asthma control and lung function (Gupta et al., 2012).
To sum up:
- Past tense is more natural for reporting verbs like “showed”, “demonstrated”, and “suggested”.
- Present tense and past tense are both okay for describing findings: present tense is stronger.
- You can even omit the reporting verb altogether for a very strong assertion.