SELF-STUDY

Verb Tenses in Scientific Writing

Although the full range of verb tenses appears in scientific writing, the most commonly used tenses are the simple present (essentially, to describe established fact) and the simple past (essentially, to describe what was done in an attempt to establish fact).

Since choice of verb tense can affect nuance (eg, whether the author(s) accepts or rejects a previous claim), authors should take care to use the appropriate tense.

Use Simple Present to refer to:

Established fact
A present state
The research paper itself

Use Simple Past to refer to:

Specific events completed in the past
A state of affairs that existed or was completed in the past

Other tenses: Use Present Perfect to refer to:

An action begun in the past that is still strongly relevant to the present time
In citations, when the cited author(s) is not named specifically

Other tenses: Use Past Perfect to refer to:

An action or state that occurred before another action or state

Other tenses: Use Simple Future to refer to:

Actions that have yet to be performed

Verb Tenses in the Different Sections of the Research Paper

Introduction section

A mixture of the Simple Present, because the section presents the background of the topic (ie, what is known and unknown about the topic), and the Simple Past, because the section concludes by describing the study’s aim (note that the aim preceded everything else in the study: the methods, results, conclusions, and paper itself) as well as the experimental approach.

Materials and Methods section

Mostly the Simple Past, because this section recounts the steps of the experiment, completed in the past.

But use the Simple Present for general statements or to describe the features of the materials or procedures.
Simple Present, to point the reader to the tables or figures.

Results section

Mostly the Simple Past, because this section describes what was found.
But use the Simple Present to refer to the research paper itself.

Discussion section

Mixture of mostly the Simple Present and the Simple Past, because this section situates the study’s findings in the context of work done thus far and draws conclusions from the facts that have been revealed by the study.

YOU TRY!

Revise the following sentences for correct verb tense.

1.: Patient characteristics were shown in Table 1.

2.: Thus, we speculated that the nucleotide transporter activity was involved in the individual differences in the pharmacokinetics of X.

3.: The pharmacokinetic profiles in plasma and erythrocytes were indicated in Figure 2.

4.: The purpose of this study is to compare the topographic characteristics of myopic and nonmyopic DH in primary open-angle glaucoma.

5.: Recent advances in the understanding of allergen sensitization also revealed the sentinel role of innate immune mechanisms involved in the development of allergic diseases [3, 4].

6.: The purpose of the present study is to clarify whether X can determine the etiological difference between NAION and anterior ON in the acute stage.

7.: Posterior segment OCT findings were shown in Fig. 2b.

8.: However, the main purpose of our study is to compare the diagnostic abilities of the Cirrus Oct with the Stratus OCT in individuals with diffuse RNFL atrophy on red-free RNFL photography, and for that, we have used the semiquantitative RNFL grading methods described by Smith et al [9].

9.: After sub-Tenon dissection was achieved, a half-thickness rectangular flap was fashioned in the superior region.

10.: Smith et al reported that laser suture lysis was associated with a higher rate of failure when low IOP criteria, but not high IOP criteria, are applied in OAG [12].

11.: (end of the Introduction) In this paper, we described a novel method for detecting Y.

12.: The human heart usually pumped about 1 L of blood around the body in 1 minute.

13.: (end of the Methods) Data are expressed as means + SDs.

14.: Situated in central Japan, Ibaraki prefecture covered an area of 6095 km² and had a population of 3 million.

15.: In the present study, we clearly showed that X and Y had distinct properties in T1009R-induced signal transduction.

ANSWERS

1.: Patient characteristics are shown in Table 1.
(Simple present tense for statements referring to the research paper itself, ie, here to a table.)

2.: Thus, we speculated that the nucleotide transporter activity is involved in the individual differences in the pharmacokinetics of X.
(The statement in the 'that' clause refers to a speculated fact, so the tense is simple present.)

3.: The pharmacokinetic profiles in plasma and erythrocytes are indicated in Figure 2.
(Statements referring to the research paper itself, ie, here to a figure, are in the simple present tense.)

4.: The purpose of this study was to compare the topographic characteristics of myopic and nonmyopic DH in primary open-angle glaucoma.
(The purpose of the study preceded any other part of it, so it is stated in the simple past tense.)

5.: Recent advances in the understanding of allergen sensitization have also revealed the sentinel role of innate immune mechanisms involved in the development of allergic diseases [3, 4].
(Statements with ‘recent’ or ‘recently’ are usually in the present perfect tense because they refer to an act or state that is still strongly relevant to the present time. In addition, ‘Recent advances’ obliquely refers to recent reports, without naming the authors of those reports specifically.)

6.: The purpose of the present study was to clarify whether X can determine the etiological difference between NAION and anterior ON in the acute stage.
(The purpose of the study preceded any other part of it, so it is stated in the simple past tense. Note that in this type of sentence, the use of ‘the present study’ can be distracting.)

7.: Posterior segment OCT findings are shown in Fig. 2b.
(Statements referring to the research paper itself are in the simple present tense.)

8.: However, the main purpose of our study was to compare the diagnostic abilities of the Cirrus Oct with the Stratus OCT in individuals with diffuse RNFL atrophy on red-free RNFL photography, and for that, we used the semiquantitative RNFL grading methods described by Smith et al [9].
(‘was’: The purpose of the study preceded any other part of it, so it is stated in the simple past tense. ‘used’: the simple past tense to refer to the completed actions of the experiment)

9.: After sub-Tenon dissection had been achieved, a half-thickness rectangular flap was fashioned in the superior region.
(The action of ‘sub-Tenon dissection’ was achieved before the ‘flap was fashioned’, so strictly speaking, it should be in the past perfect tense.)

10.: Smith et al reported that laser suture lysis is associated with a higher rate of failure when low IOP criteria, but not high IOP criteria, are applied in OAG [12].
(The simple present tense indicates that this finding by Smith et al is considered established fact. If the verb remains in the simple past tense, the authors are suggesting that they do not consider the claim of Smith et al to be fact. In addition, the verb in the second part of the sentence, ‘are applied,’ is in the simple present tense, so the tense of both verbs should be revised for consistency: either both simple present, if the authors believe that Smith et al’s claim is fact, or both simple past, if the authors do not. Also, note that ‘reported’ is in the simple past tense because this is a completed action in the past and the cited authors are specifically named.)

11.: (end of the Introduction) In this paper, we describe a novel method for detecting Y.
(The action refers to the research paper itself, so the tense is simple present.)

12.: The human heart usually pumps about 1 L of blood around the body in 1 minute.
(General statements of fact/established knowledge are given in the simple present tense.)

13.: (end of the Methods) Data were expressed as means + SDs.
(The tense is simple past because the statement refers to a completed step in the experiment, ie, a step completed at the time of the statistical analysis.)

14.: Situated in central Japan, Ibaraki prefecture covers an area of 6095 km² and has a population of 3 million.
(Simple present tense to describe established fact, as well as the general features of a place/device/person, etc.)

15.: In the present study, we clearly showed that X and Y have distinct properties in T1009R-induced signal transduction.
(Simple present tense because this statement refers to a fact that has been revealed by the present study. You may also have changed ‘clearly showed’ to ‘have clearly shown’. This revision is also possible and implies that what the study showed is still strongly relevant to the present time.)