There are various questions about this, but none that I found provided me with a satisfying answer. My problem lies mainly in the part of the paper were I introduce the necessary background, and in particular explain what papers have introduced what ideas. Consider the sentence:

John and Doe have introduced an algorithm to do X in [47], which has been substantially improved in [11].

Should I use present perfect or past tense here? I am confused, because many style guides (e.g., this one or this) advise using the past tense; on the other hand, I've been taught in school something about if action is still ongoing or just completed, if the time is unspecified, and if the result is relevant. Based on the latter aspect, I'd say sure, the introduction of the algorithm in [47] and its improvements in [11] are highly relevant to what I write, so I'd use the present perfect. Am I right or wrong in this?

  • 2
    I would suggest using the present perfect only if the papers in question are fairly recent, and you are introducing them to your readers as something new. Feb 8, 2023 at 13:52
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    What style guide advises against using the past tense? What contexts are the style guides referring to?
    – alphabet
    Feb 8, 2023 at 16:33
  • @alphabet see edit.\
    – Bubaya
    Feb 8, 2023 at 17:31
  • The first clause needs past tense and an article an before algorithm. This is the prior situation, and is now past. The second clause needs the perfect, in its Stative/Resultative sense,, which is used to indicate that the direct effect of a past event still continues in the present (e.g, I can't come to your party tonight - I've caught the flu). The improvements are present relevance. Feb 8, 2023 at 17:44
  • have introduced algorithm to do x is not grammatical in English, and not because of the verb.
    – Lambie
    Feb 8, 2023 at 19:47

3 Answers 3


As the poster writes, style guides differ, and practice differs between fields. As a biological scientist who later in his academic career moved into bioinformatics I was surprised at what seems to me the bizarre way many computing sciences articles use the present tense where I have always used the past tense.

My advice — which editors and referees in other fields may reject — is to do what people in my field do. I would say that, wouldn’t I? But the simple justification is that this is the form used in normal English. Normal English will be comprehensible to the reader, and the purpose of a scientific communication is to present results or ideas in a way that can be understood.


John and Doe introduced (note 1) an algorithm to do X (note 3) [47], which has been (note 2) substantially improved by Jack and Jill (note 4) [11].

1, 2. Both papers referred to were published in the past. The past tense is therefore appropriate. However, with one published before the other I think it better (and normal English usage) to employ the simple past (introduced) for the original and the perfect tense (has been improved) for the more recent publication.
3,4. I have changed the citation by removing the word ‘in’. This was not a response to the question, but if we are talking about scientific writing stye… Why? It is unnecessary in the first case, and sounds odd read out loud. In the second case, for consistency, I would prefer to include the names of the authors of the improvement (or use ‘they’ if the same as the original). Alternatively just put ‘[11]‘ directly after the word ‘improved‘, without an intervening space.

  • +1 Exactly. Write like your favorite writers (and scientists, in a scientific context). Why write like anybody else? I always told people thinking of graduate study to find out where their favorite academic -- the person whose works made you excited about the field -- and apply to study there, with them. Same advice for writing; if you can't afford to go study with them, read what they write and do likewise. Mar 11, 2023 at 18:02
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    Apologies for crucial typo. I avoid naming past tenses technically as usage varies and I am not a language teacher. But all I am proposing is that native English speakers use tenses as they would in natural language or non-technical writing, and that non-native speakers try to find the best examples to emulate (as @JohnLawler wisely suggests.)
    – David
    Mar 11, 2023 at 23:47

Those style guides are written for scientists in general, not for people with a sophisticated understanding of English grammar. I find it highly unlikely that, by prescribing the use of the past tense to describe past events, they mean to require the simple past and prohibit the present perfect.

Neither of them even mention the present perfect (or use the phrase "simple past" specifically), and it would be extremely unusual for a style guide to recommend against the usage of the present perfect in general, much less to do so without explicitly stating as much. I suspect that they would just lump it in with the past tense.

Assuming you follow the usual rules about when the present perfect is appropriate, there is no reason to avoid it in a scientific paper.

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    I don't think it's because stupid scientists can't understand basic grammar, but certainly scientific and academic writing has its own conventions that differ from normal English.
    – Stuart F
    Feb 9, 2023 at 10:33
  • It's because people who write grammar guides don't understand grammar. They're concerned with "correctness" instead of communication. Mar 11, 2023 at 18:03
  • @StuartF I'm actually quite confident that the authors of this guide either failed to consider the use of the present perfect entirely or thought of it as some kind of past tense. Style guides very frequently demonstrate a lack of understanding of the very basics of English grammar, even ones written by people who should really know better (cough Strunk & White cough).
    – alphabet
    Mar 11, 2023 at 19:26
  • Green-eyed condescending attitude . Mar 12, 2023 at 5:16

An advice strongly reiterated to me to use the past participle, is neutrality.

To state the state of the door, not that the door is being painted.

  • The door is painted in Scene 2 Act 5.

To state the state of the scene, not that the gun is being drawn.

  • The gun is drawn at the end of chapter 2.

The professors were very adamant, that we should not attribute a scientific work to the wrong endeavour, or time frame. We should focus on the precision and details of the thesis, using precise, concise and proper language, rather than writing a descriptive novel. We should not provide distraction to one's endeavour in the precision of the description of our work, nor provide distraction to the professionals who need to understand our work.

To say, a piece of work has been substantially improved in [ref], would imply the substantial improvement was made within writing or performing of [ref], not that [ref] describes an endeavour before [ref] was written or performed.

However, to say, a piece of work is substantially improved in [ref], would describe the state of affairs published in [ref].

  • I don't think this addresses my question, since your sentences are present tense passive sentences, which, of course, make sense because they make statements about a play. I don't think I understand your second but last paragraph.
    – Bubaya
    Mar 13, 2023 at 9:56
  • "Is painted" is not "present". It is a past/completed participle. A present participle would be like "running". Read up on participle vs tense. Mar 13, 2023 at 10:57
  • Present tense passive voice, as in your examples, is present tense, even if it is formed using past participle.
    – Bubaya
    Mar 13, 2023 at 15:20
  • Rather the past participle is formed with a past tense , and denote hitherto present state due to an action performed in the past. A past particle is not "present" tense thought it may be used by present auxiliary conditons. Mar 17, 2023 at 16:50

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