I am writing an academic paper, and I need to use demonstrated or proof words. I always use that after these words. I really not sure if this is correct or not.

Here is an example,

The paper demonstrated that method A outperforms method B.


The paper proved that method A outperforms method B.

Are my sentences correct?

  • I see no problem with using "that" in your examples. You should use present perfect time though, so "the paper has demonstrated" and "the paper has proved."
    – Jan
    Jul 1, 2019 at 8:42
  • @Jan thank you so much. You make me happy :)
    – Mary
    Jul 1, 2019 at 8:44
  • @Jan There's nothing wrong with the verb tenses used in the original sentences. If you want to use present perfect (which is also fine) that's entirely up to you. It's simply a matter of style and preference. There is no should about it here. Certainly not without additional context that would put them alongside otherwise sentences. (If the sentence follows What did the paper do? you certainly would not use the present perfect.) Jul 1, 2019 at 14:25
  • I was probably thinking it should be "have demonstrated" because the next verb "outperforms" is in the present simple. I have a problem thinking how could "demonstrated" in the past tense and "outperforms" in the simple tense go together. Maybe both "demonstrated" and "outperformed" should be in the past tense. Because, very likely, "method A" and "method B" existed only in the study and they do not exist outside of the study, so they do not exist in the present tense.
    – Jan
    Jul 2, 2019 at 8:34

1 Answer 1


Using "that" after "demonstrate" and "prove" is perfectly fine. Actually, I would have to make an effort to find another correct way to use those words (and I doubt that it exists).

If the demonstration is in the current paper, it sounds awkward (to me, at least) to use the past tense. I would actually use the present tense, because you speak / write about something actual. Things would be different if you would write about a paper written by e.g. Isaac Newton.

Regarding the tenses used, there might be one exception: the rule-book of the university, about how to write papers. Sometimes they go into crazy details about what is allowed and what is frowned upon.


I just understood (in my own head) that other words can be used, with the respective change in the meaning:

  • The paper proves if / when / where (something will happen).
  • The paper proves what (will happen).
  • The paper proves who (will do something).

Now I assume that other words might still exist :)

Other examples, kindly provided by @JasonBassford, proving that that is not always needed:

(1) The paper demonstrated a fair degree of intelligence.

(2) My efforts proved successful.

  • (1) The paper demonstrated a fair degree of intelligence. (2) My efforts proved successful. It would be ungrammatical to insert that into these particular constructions. So, there are certainly counterexamples with the use of demonstrate and prove Context will also determine the tense used. There are cases where the past tense would be appropriate and the present tense would not. You are overgeneralizing the situation. Jul 1, 2019 at 14:29
  • @JasonBassford: Your comments fit exactly my second part of the answer, when I got smarter :)
    – virolino
    Jul 2, 2019 at 5:17

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