I am writing a research paper and found that some paper use present tense to describe the previous studies. For example,

There are several surveys which summarize the existing opinion mining work [9, 21, 14]

But some sentences use Past tense:

Zhou and Chaovalit performed sentiment classification on reviews using domain ontology database.

When we want to talk about what has been done in the past in terms of research contribution, what is the general rule to choose between Present and Past tense?

  • This isn't an English question, really... It's more of a question for Academia, I think. I don't believe that there's any rule for it.
    – Catija
    Commented Apr 5, 2016 at 19:04
  • Based on my observation, if some works have a long lasting impact, then I should use Present tense. But for a particular task or action that are done in the past, I should use Past tense. I just want to confirm if this is correct. Thanks!
    – unki
    Commented Apr 5, 2016 at 19:07
  • @Catija: I must politely disagree. The content of the examples is Academia, but it belongs here as much as, say parsing the tenses used in a Harry Potter novel belongs here rather than in Scifi SE. The heart of the question is "Why are these examples, taken from the same work, use different tenses for different references.
    – sharur
    Commented Apr 5, 2016 at 19:29

1 Answer 1


Both (Sorry). References to a study (or more accurately the paper summarizing the results, see note at bottom) generally use the present tense, while references to actual researchers generally use past. And unless your research subject is English language, you will see variations.

To explain the examples you gave:

  1. Firstly, "are" in this context means "exist". So one could rewrite the sentence as "there exist studies that...". Sencondly, the studies* still exist, and they still currently (as of writing) summarize opinions on mining work. Incidentally, they will always summarize opinions on mining work; it's just that the opinions will eventually no longer be current as of time of reading. Thus, because the studies still exist, we use the present tense.

  2. Zhou and Chaovalit are the actors here. They are (presumably) no longer performing sentiment classification, thus the action is in the past, and we use past tense. Actually, if Zhou and Chaovalit are continuing to work on this subject, we can use the past tense as we are not referring to their current work at all, but their past, published work (and findings, see note below)

*One thing to note: "Study"(singular form of "studies") as a noun, in this context, can refer to both the actual study itself(the research, testing, test subjects, etc.) and to the report(s) detailing the study and its results. The second option is probably intended here.

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