Here’s the rule in one line: when you cite a study, the verb that reports it goes in past tense (“Gupta et al. showed…”), and the verb that describes what they found can go in present tense if you want the finding to still sound true today (“…that X is associated with Y”). Same sentence, two verbs, two different jobs — and mixing them up is one of the quietest ways an introduction ends up sounding either overconfident or oddly dated.
This is Writing Tip 7, and it’s one of the most-flagged issues we see in introduction sections, precisely because both tenses are grammatically fine. Nobody’s spellchecker catches it. It just reads slightly off, and most authors can’t say why.
The two-verb structure
Almost every citation sentence in an introduction has two verbs doing different work:
Gupta et al. (2012) showed that increased soil salinity was associated with reduced yield.
“Showed” is the reporting verb — it tells the reader an event happened, and that event is safely in the past, so past tense is the natural choice. You can write “shows,” and it isn’t wrong, but it tends to read as affected, like narrating a study as if it’s happening live in front of you. Past tense is the boring, correct default here, and boring is what you want.
“Was associated” is the finding verb, and this is where you actually have a choice worth making. Write it in past tense and you’re saying: this is what that particular study found, in that particular dataset, at that particular time. Write it in present tense — “is associated with” — and you’re saying something stronger: this isn’t just a historical result, it’s still how the world works.
That’s the whole trick. The reporting verb almost always stays past. The finding verb is your dial between “this happened once” and “this is true.”
Why you’d deliberately choose the weaker one
Here’s the part that surprises people: past tense on the finding verb isn’t a mistake to avoid, it’s a tool. If you’re about to introduce a study that contradicts or updates an older one, putting the older result in past tense does some of the argumentative work for you before you’ve said a single evaluative word.
“Early work suggested that X caused Y. More recent studies show that X causes Y only under specific conditions.” You haven’t written “however” or “in contrast” anywhere in there, and the reader still feels the shift, because the tense told them which claim is closed and which is current. That’s a genuinely useful piece of grammar to have deliberate control over, not just correct usage of.
There’s also a stronger move still: drop the reporting verb entirely when you already have a citation doing that job. “Increased soil salinity is associated with reduced yield (Gupta et al., 2012)” reads as more assertive than the version with “showed that” in it, because you’re no longer hedging behind who found it — you’re just stating it, with the source attached as evidence rather than as the subject of the sentence. Use it when you want the claim to carry the sentence, not the study.
The related rule this isn’t
One thing this rule doesn’t cover: describing a broad trend in the field rather than one study’s finding — “the contribution of agricultural production to greenhouse gas has long been debated” — which usually wants present perfect, not simple past. That’s a separate call with its own triggers (dates in the sentence push you back to simple past), and it’s covered in Writing Tip 6 if you want it next.
If it’s easier to see this in action than read it, there’s a short video walkthrough on exactly this — how the verb tense you pick actually changes the meaning of a citation sentence, not just its formality.
A quick check for your own introduction
Go through your citation sentences and ask, for each one: is the reporting verb past tense (it almost always should be), and did I choose the finding verb’s tense on purpose, or just copy whatever tense the last sentence happened to be in? That second habit — tense drifting sentence to sentence rather than being chosen — is the one that actually shows up in edited manuscripts more than any single “wrong” tense does.
It’s a small thing to fix and it’s exactly the kind of small thing a second pair of eyes catches faster than the person who wrote the sentence, because you already know what you meant — a reader doesn’t. If you’d rather have an editor go through the introduction line by line for this and everything else, that’s what Academic English Editing Level 3 is for. There’s also a whole e-book on tense choices through the introduction section, How to Master Verb Tense in the Introduction Section, on Uni-edit’s book site if you want to go deeper than one blog post can.
And if tense questions like this one are the kind of thing you’d rather have land in your inbox before you’re staring at a deadline, you can sign up for the writing tips — this was one of fifteen, and the rest cover the same kind of quietly-wrong-not-technically-incorrect problem.
A course on this, if enough people want one
Tips like this one are the raw material for Academic Writing Essentials, a short course we are thinking about building. It does not exist yet. If it would be useful, add your name and tell us what it should cover.
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