Some believe that you should not use the active voice in formal scientific writing because scientific writing should be impersonal. While others like APA style or standford writing in science course prefer active voice basically to be concise (cut the words). However, the active voice is not necessarily ‘personal’ as many actors can be ‘non-person’. For example, ‘Process X improves yield.’ is more concise than ‘Yield is improved by using process X.’ And sometimes the actors too unimportant to begin a sentence. Both the active or passive voice have pros and cons. More resonably, the use of them should be dependent on
- the clear and concise of a sentence: usually a verb should not be far away from the start of a sentence. Thereby passive voice where the subject is too long should be avoided
- the utility (emphasis, intention) of a sentence and sometimes a paragraph or a section
- the style of language with which supervisors and co authors feel most comfortable
- guidance of your target journal
In essense, active voice stresses that the actor (or grammatical subject) precedes the verb. Passive voice construction leaves out the actor (subject) and focuses on the relationship between the verb and object. And in general, the most readable text is a combination of appropriate active and passive voice.
Abstract examples
Copied from the University of Oxford Scientific writing training resources where they adapted the abstracts from a plos one paper.
the active style (combination) is more clear
passive style (9 instances of passive voice, 131 words)
Biosecurity is defined as a set of measures to protect animals and crops from the risk of disease. It is considered important in pig production, and several routine measures are employed by farmers (e.g. cleaning, disinfection, segregation). However, air as a potential vector of pathogens has long been disregarded. Filters for incoming and recirculating air were installed into the ventilation system of one of two barns at a fattening piggery. Over three consecutive fattening periods, the lung health of pigs in the filtered compared with the unfiltered barn was evaluated. Air filtration was easily introduced into the existing ventilation system. Better lung health was found in animals from the barn equipped with recirculating air filtration modules. Therefore, air filtration systems in animal rearing enclosures should be recommended by animal healthcare professionals.
active style (6 instances of active and 3 passive voice, 122 words)
Biosecurity is defined as a set of measures to protect animals and crops from the risk of disease. It is important in pig production, and farmers routinely employ several measures (e.g. cleaning, disinfection, segregation). However, air as a potential vector of pathogens has long been disregarded. We installed filters for incoming and recirculating air into the ventilation system of one of two barns at a fattening piggery. Over three consecutive fattening periods, we compared the lung health of pigs in the filtered and unfiltered barn. Air filtration was easily introduced into the existing ventilation system. Animals had better lung health in the barn equipped with recirculating air filtration modules. Therefore, animal healthcare professionals should recommend air filtration systems in animal rearing enclosures.
Introduction section
The aim of an introduction is to provide background, context, prior knowledge, heuristics or an in-depth explanation. It is usually objective and inpersonal, thereby passive voice is usually appropriate.
Results section
with an intention of intriguing results section, where the readers can follow the flow of thoughts:
- [active] you asked a question or state an aim
- which methods were adopted
- [passive] when the method was well-defined before your study
- [active] when the method was developed for this study and is wordy to summarize
- directly state the phenomena, avoid using a phenomena ‘was observed’, ‘was determined/identified/found’, because of redundancy as it’s implied already as it’s a part of results section
- [active]’measurement’/’research object’ + ‘verb’ or ‘treatment/action’ + ‘active verb’ + ‘measurement/research object’
- [passive] if strongly emphasize the phenomena and only imply the treatment or condition (depends on how long the sentence is before ‘by treatment/condtion’): ‘measurement’/’research object’ + ‘passive verb’ + ‘by treatment/condition’. Note that this can be wordy
Methods section
Passive voice is usually appropriate because here the subject can be redundant and repetitive, where most actions were taken by the same researchers and the researchers’ identities are not important.
Counts of ‘We ‘ in recent Nat Comms Biological sciences papers
Consider that active voice encompasses more than’We ‘, this is a narrower investigation; but you already see it’s varied.
