I’ll briefly talk about the key considerations for choosing tenses as you write your essays, so that you understand what tense to use in particular situations, and why the choice of tense has to be consistent in your writing.
I believe this topic has concerned you quite a lot, especially when you hope that you make fewer grammatical mistakes in your writing. I assume that you have understood that English verbs are time-sensitive, meaning that the verb form changes when you describe an action occurring at different times, and status-sensitive, in that the verb form changes based on whether the action is repeating, ongoing or complete.
This means that you have to think about verb tense in terms of “time” and “aspect”. Marking the time of action in some languages like Cantonese or Chinese does not change the verb form, but instead use markers representing that the action is complete or not, like “le” or “zo” working similarly as the adverb “already” in English. Along this logic, it isn’t hard to understand that some English learners would use present perfect tense frequently in writing, in place of the simple past tense, when they describe a past action.
In academic writing, we can simplify our understanding about time, for the sake of consistency. We can treat anything happening before the time our essay is written as the past in general, the actions happening in our essay as present, and those after the essay as future.
This means that, when you cite references, use the simple past tense (e.g. Cheung (2021) argued that…). When you are talking about the methods you took to analyse your subject matter before you write, use past tense (e.g. To collect data, I conducted a questionnaire survey… and received 1,000 valid responses.)
When you talk about what you are doing in your essay, use the present tense (e.g. In this essay, I first describe X… examine Y… and conclude with four recommendations…). When you describe general facts about the subject matter, concepts or theories, use the present tense (e.g. The term “cancel culture” refers to…). Meanwhile, use present perfect tense when you talk about what you finish doing in your essay, like in the conclusion (e.g. This study has analysed X in order to examine Y.)
When you give predictions, talk about future research, recommending solutions, or anything about the future, use the future tense (of course). You may also use modal verbs related to future actions or suggestions. I’ll talk about modality in detail later in the semester.
The above suggestions perhaps give you some ideas not just about what tense you should use in a particular part of your essay, but also why the tense choice should be consistent. This may surprise you, because this is not just for accuracy: the consistency in tense choice represents two main criteria for effective organization – cohesion and coherence.
In terms of cohesion, a consistent choice of tense “glues” together the ideas in the same “time zone”. You cannot probably talk about the methods you used in both past and present terms. This also suggests that, if you’re able to talk about ideas in the same time zone, the text also achieves logical coherence, since you aren’t wandering randomly in time (as if you could).
Also, by separating “time zones” between previous research studies and your study, you can create a sense that your paper is more updated, and make an attempt to renew the discussion, modify methods, or even propose new thoughts. This potentially gives the readers the impression that you are confident in contributing something new to the academic discussions. Of course, you may find some expert articles would use the present tense citing references. We’ll talk about the “historical present tense” later. So now the main concern is therefore not just getting the tense forms correctly, but also becoming more aware about choosing tense to enhance the logic and organisation, and the overall quality of your paper.