Categories
Sentence construction

Don’t (always) be passive

Take-home: active constructions are usually best, but the passive voice is sometimes appropriate.

Writing guides rarely say anything positive about the passive voice (positive things are rarely said about the passive voice by writing guides). However, scientists carry on using it, as in:

‘Seed is widely considered to be an important input to agriculture.’

or

‘The survey tool was developed in consultation with farmers’ representatives and local experts.’

So, what is wrong with the passive voice?

Two main things.

First, a phrase like ‘The survey tool was developed in consultation with …’ is ambiguous, unless the authors make it clear elsewhere that they did the developing. 

Sometimes, the ambiguity may be deliberate; for example, some may feel more comfortable in hiding behind a phrase like:

‘It seems likely that incomes will continue to fall.’

rather than making a clear assertion like:

‘We think it likely that incomes will continue to fall.’ 

Deliberate ambiguity is perhaps acceptable in politics and law, but not normally in science.

Second, passive construction is more difficult for the brain to process. We seem to be programmed for the standard subject–verb–object sequence:

‘We analyzed the soil samples.’

is easier on the brain than:

‘The soil samples were analyzed by us.’

In spite of this, the passive voice is very common in scientific writing. Scientists don’t tend to be bashful about their work and the credit due to them, so I doubt that this is due to modesty. I suspect that scientists’ sharp focus (obsession, even) on the subject of their research is one explanation. These subjects often correspond to the objects of active sentences (‘We weighed the adult turtles‘). When scientists write, what is foremost in their minds (research subject, grammatical object) spills out first, and the rest of the sentence is then built around it:

‘The adult turtles, defined as all individuals that had reached sexual maturity, were fitted with tracking devices, and then measured and weighed before release.’

Such writing is indeed passive, because we are going with the flow of our thoughts, rather than thinking how best to express them.

However, the passive may sometimes be the best choice. We may want to stress or make a specific point about the object of the sentence:

‘Focus groups, rather than individual interviews, were used because of time limitations.’

may work better than:

‘Because of time limitations, we used focus groups, rather than individual interviews.’

Or

‘Ronald Fisher is considered by some to have been the father of quantitative genetics.’

may work better than:

‘Some consider Ronald Fisher to have been …’

The passive voice can also be appropriate in two standard components of scientific articles: the Methods section and the Abstract. Readers often scan abstracts without looking at the list of authors, in which case the impersonal feel of the passive seems natural. In Methods sections, careless use of the passive may lead to ambiguity (see above), but in simple descriptions of procedures it can be more elegant than multiple repetitions of ‘I’ or ‘we’. In both cases, our experience as readers also aids comprehension: we are used to finding the passive in these sections, and therefore find it easier to process when it appears.

In general, though, neither concision nor clarity are well served by the passive voice. Careful re-reading of first (or even final) drafts usually reveals multiple cases of passive sentences that would be better phrased as active constructions. the passive voice enhances neither concision nor clarity. Careful re-reading of first (or even final) drafts usually reveals multiple cases of passive sentences that writers could usefully rearrange as active constructions. So, use the passive when appropriate … but don’t be passive about it!

Categories
Abstracts Sentence construction

Should my abstract be long and wordy?

Take-home: recent research unexpectedly found that papers with longer, wordier abstracts tended to have more citations. But that doesn’t mean that scientists should deliberately write ‘indigestible’ abstracts.

A 2015 article by Weinberger et al. found that papers with abstracts that follow standard ‘rules’ (e.g., ‘keep it short’, ‘keep it simple’, ‘keep it compact’) tended to have fewer citations. The result was not uniform across disciplines or across all ten rules they examined but, overall, was both striking and strongly counterintuitive.

The authors suggest—possibly with tongues-in–cheek—that:

‘Scientists are skeptical by disposition, and this exercise shows that, rather than taking advice at face value, they can apply the same machinery they use to interrogate nature to put these recommendations to the test—and write a lengthy, convoluted, highly-indexible, self-describing abstract.’

They based their analysis on an automated survey of more than one million abstracts across eight disciplines. They suggested that the results were probably explained by search engines favouring longer abstracts (‘longer, more detailed, prolix prose is simply more available for search’).

I wonder whether an attentive read of a much smaller sample, with metrics more sophisticated than, for example, sentence length, would have produced different results. Either way, the above comment makes sense only if scientists’ aim is to achieve high citation rates. What scientists should seek is to have both high citation rates and to ensure that their papers communicate the results of their research accurately and readably. This aim cannot be achieved by writing convoluted abstracts.

Categories
Document structure

Where are the conclusions?

Take-home: Use a separate Conclusions section if the journal allows it and if you think it improves clarity, but be cautious with combined Results and Discussion sections.

I was puzzled recently by someone’s comment that a paper I was reading didn’t have any conclusions—until I realised that the speaker meant that it didn’t have a section titled ‘Conclusions’. I explained, too dogmatically, that in the classic IMRD structure, an important role of the Discussion section is to draw conclusions through interpretation of the results. At the same time, the observation made me reflect on how articles are structured.

IMRD:

  • Introduction
  • Methods (and materials)
  • Results
  • Discussion

The use of an Introduction section and a Methods section is still pretty much sacrosanct (even if some important journals like PNAS prefer to relegate Methods to a small-type section at the end). By contrast, the presentation of results, discussion, and conclusions is quite variable. Here is my take on some of the pros and cons of both pure IMRD (separate Results and Discussion sections, no Conclusions section) and two common departures from it: the combined Results and Discussion section and the separate Conclusions section.

SystemProsCons
(A) Separate Results and Discussion sections.
No Conclusions section.		Promotes clarity of distinction between results and their interpretation.
If done well, makes for an elegant and persuasive transition from results to conclusions.
The Results section may seem very short and ‘dry’.
Not everyone has the writing skills needed to ensure that the discussion argues smoothly and persuasively from results to conclusions.
(B) Combined Results and Discussion section.Easier to write than (A); removes risk of having a very short Results section.It risks blurring the distinction between results and their interpretation, removing a stimulus to clear thinking.
Unless (C) is also used, the paper is reduced to three sections.
(C) Separate Conclusions section.Conclusions are clear.
Easy to write.		The Discussion section is more difficult to write if the conclusions are removed from it; it has no climax to build towards and renders it inconclusive (literally).

How to weigh these pros and cons? The sensible approach is to ask how they affect the communication of the results of research. I suggest that:

  • A short and ‘dry’ Results section should not be a problem (if anything, quite the contrary). For example, a Results section may consist only of a single sentence such as ‘There was no significant difference between treatments (p=0.35) (Table 1); mean values were similar to each other (Table 2)’. Such brevity says nothing about the importance of the results (imagine, for example, that this referred to an experimental trial of a new vaccine).
  • In science, the distinction between fact and opinion or interpretation is important. A separate Results section leaves results bare and blinking in the light of reason and enables readers to quickly appreciate what the results are—as opposed to what the authors’ view of them is).
  • It is difficult to mount a serious argument against the separate Conclusions section, particularly for those who struggle to write a well-structured discussion. Readers, too, will often appreciate a separate Conclusions section.
  • The separate Conclusions section may aid clarity, but in many cases it duplicates (under the guise of reiteration) what’s already in the Results and Discussion. Clarity should not be secured at the expense of concision. If you have a separate Conclusions section, don’t also state your conclusions in the Discussion.

Use a separate Conclusions section if it helps you to communicate your findings and if the journal permits it … but careful with the combined Results and Discussion!