passive voice literature review

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Active Versus Passive Voice

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Active voice is used for most non-scientific writing. Using active voice for the majority of your sentences makes your meaning clear for readers, and keeps the sentences from becoming too complicated or wordy. Even in scientific writing, too much use of passive voice can cloud the meaning of your sentences.

The action is performed upon the sentence subject, meaning this sentence is passive (indirect).

This is an example of the active voice because the sentence subject performs the action.

This is an example of the passive voice.

This is an example of an active voice sentence because the sentence subject performs the action.

This is an example of an active voice sentence because its subject performs the action expressed in the verb.

Sentences in active voice are also more concise than those in passive voice because fewer words are required to express action in active voice than in passive.

This passive voice sentence is less concise than its active voice counterpart (shown below).

This active voice sentence requires fewer words to communicate the same idea as the passive voice version (above).

This passive voice sentence is more wordy than an active voice version.

This active voice sentence is more concise than the passive voice version (above) because the subject directly performs the action.

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Open Access

Ten Simple Rules for Writing a Literature Review

* E-mail: [email protected]

Affiliations Centre for Functional and Evolutionary Ecology (CEFE), CNRS, Montpellier, France, Centre for Biodiversity Synthesis and Analysis (CESAB), FRB, Aix-en-Provence, France

• Marco Pautasso

Published: July 18, 2013

• https://doi.org/10.1371/journal.pcbi.1003149
• Reader Comments

Citation: Pautasso M (2013) Ten Simple Rules for Writing a Literature Review. PLoS Comput Biol 9(7): e1003149. https://doi.org/10.1371/journal.pcbi.1003149

Editor: Philip E. Bourne, University of California San Diego, United States of America

Copyright: © 2013 Marco Pautasso. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding: This work was funded by the French Foundation for Research on Biodiversity (FRB) through its Centre for Synthesis and Analysis of Biodiversity data (CESAB), as part of the NETSEED research project. The funders had no role in the preparation of the manuscript.

Competing interests: The author has declared that no competing interests exist.

Literature reviews are in great demand in most scientific fields. Their need stems from the ever-increasing output of scientific publications [1] . For example, compared to 1991, in 2008 three, eight, and forty times more papers were indexed in Web of Science on malaria, obesity, and biodiversity, respectively [2] . Given such mountains of papers, scientists cannot be expected to examine in detail every single new paper relevant to their interests [3] . Thus, it is both advantageous and necessary to rely on regular summaries of the recent literature. Although recognition for scientists mainly comes from primary research, timely literature reviews can lead to new synthetic insights and are often widely read [4] . For such summaries to be useful, however, they need to be compiled in a professional way [5] .

When starting from scratch, reviewing the literature can require a titanic amount of work. That is why researchers who have spent their career working on a certain research issue are in a perfect position to review that literature. Some graduate schools are now offering courses in reviewing the literature, given that most research students start their project by producing an overview of what has already been done on their research issue [6] . However, it is likely that most scientists have not thought in detail about how to approach and carry out a literature review.

Reviewing the literature requires the ability to juggle multiple tasks, from finding and evaluating relevant material to synthesising information from various sources, from critical thinking to paraphrasing, evaluating, and citation skills [7] . In this contribution, I share ten simple rules I learned working on about 25 literature reviews as a PhD and postdoctoral student. Ideas and insights also come from discussions with coauthors and colleagues, as well as feedback from reviewers and editors.

Rule 1: Define a Topic and Audience

How to choose which topic to review? There are so many issues in contemporary science that you could spend a lifetime of attending conferences and reading the literature just pondering what to review. On the one hand, if you take several years to choose, several other people may have had the same idea in the meantime. On the other hand, only a well-considered topic is likely to lead to a brilliant literature review [8] . The topic must at least be:

• interesting to you (ideally, you should have come across a series of recent papers related to your line of work that call for a critical summary),
• an important aspect of the field (so that many readers will be interested in the review and there will be enough material to write it), and
• a well-defined issue (otherwise you could potentially include thousands of publications, which would make the review unhelpful).

Ideas for potential reviews may come from papers providing lists of key research questions to be answered [9] , but also from serendipitous moments during desultory reading and discussions. In addition to choosing your topic, you should also select a target audience. In many cases, the topic (e.g., web services in computational biology) will automatically define an audience (e.g., computational biologists), but that same topic may also be of interest to neighbouring fields (e.g., computer science, biology, etc.).

Rule 2: Search and Re-search the Literature

After having chosen your topic and audience, start by checking the literature and downloading relevant papers. Five pieces of advice here:

• keep track of the search items you use (so that your search can be replicated [10] ),
• keep a list of papers whose pdfs you cannot access immediately (so as to retrieve them later with alternative strategies),
• use a paper management system (e.g., Mendeley, Papers, Qiqqa, Sente),
• define early in the process some criteria for exclusion of irrelevant papers (these criteria can then be described in the review to help define its scope), and
• do not just look for research papers in the area you wish to review, but also seek previous reviews.

The chances are high that someone will already have published a literature review ( Figure 1 ), if not exactly on the issue you are planning to tackle, at least on a related topic. If there are already a few or several reviews of the literature on your issue, my advice is not to give up, but to carry on with your own literature review,

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The bottom-right situation (many literature reviews but few research papers) is not just a theoretical situation; it applies, for example, to the study of the impacts of climate change on plant diseases, where there appear to be more literature reviews than research studies [33] .

https://doi.org/10.1371/journal.pcbi.1003149.g001

• discussing in your review the approaches, limitations, and conclusions of past reviews,
• trying to find a new angle that has not been covered adequately in the previous reviews, and
• incorporating new material that has inevitably accumulated since their appearance.

When searching the literature for pertinent papers and reviews, the usual rules apply:

• be thorough,
• use different keywords and database sources (e.g., DBLP, Google Scholar, ISI Proceedings, JSTOR Search, Medline, Scopus, Web of Science), and
• look at who has cited past relevant papers and book chapters.

Rule 3: Take Notes While Reading

If you read the papers first, and only afterwards start writing the review, you will need a very good memory to remember who wrote what, and what your impressions and associations were while reading each single paper. My advice is, while reading, to start writing down interesting pieces of information, insights about how to organize the review, and thoughts on what to write. This way, by the time you have read the literature you selected, you will already have a rough draft of the review.

Of course, this draft will still need much rewriting, restructuring, and rethinking to obtain a text with a coherent argument [11] , but you will have avoided the danger posed by staring at a blank document. Be careful when taking notes to use quotation marks if you are provisionally copying verbatim from the literature. It is advisable then to reformulate such quotes with your own words in the final draft. It is important to be careful in noting the references already at this stage, so as to avoid misattributions. Using referencing software from the very beginning of your endeavour will save you time.

Rule 4: Choose the Type of Review You Wish to Write

After having taken notes while reading the literature, you will have a rough idea of the amount of material available for the review. This is probably a good time to decide whether to go for a mini- or a full review. Some journals are now favouring the publication of rather short reviews focusing on the last few years, with a limit on the number of words and citations. A mini-review is not necessarily a minor review: it may well attract more attention from busy readers, although it will inevitably simplify some issues and leave out some relevant material due to space limitations. A full review will have the advantage of more freedom to cover in detail the complexities of a particular scientific development, but may then be left in the pile of the very important papers “to be read” by readers with little time to spare for major monographs.

There is probably a continuum between mini- and full reviews. The same point applies to the dichotomy of descriptive vs. integrative reviews. While descriptive reviews focus on the methodology, findings, and interpretation of each reviewed study, integrative reviews attempt to find common ideas and concepts from the reviewed material [12] . A similar distinction exists between narrative and systematic reviews: while narrative reviews are qualitative, systematic reviews attempt to test a hypothesis based on the published evidence, which is gathered using a predefined protocol to reduce bias [13] , [14] . When systematic reviews analyse quantitative results in a quantitative way, they become meta-analyses. The choice between different review types will have to be made on a case-by-case basis, depending not just on the nature of the material found and the preferences of the target journal(s), but also on the time available to write the review and the number of coauthors [15] .

Rule 5: Keep the Review Focused, but Make It of Broad Interest

Whether your plan is to write a mini- or a full review, it is good advice to keep it focused 16 , 17 . Including material just for the sake of it can easily lead to reviews that are trying to do too many things at once. The need to keep a review focused can be problematic for interdisciplinary reviews, where the aim is to bridge the gap between fields [18] . If you are writing a review on, for example, how epidemiological approaches are used in modelling the spread of ideas, you may be inclined to include material from both parent fields, epidemiology and the study of cultural diffusion. This may be necessary to some extent, but in this case a focused review would only deal in detail with those studies at the interface between epidemiology and the spread of ideas.

While focus is an important feature of a successful review, this requirement has to be balanced with the need to make the review relevant to a broad audience. This square may be circled by discussing the wider implications of the reviewed topic for other disciplines.

Rule 6: Be Critical and Consistent

Reviewing the literature is not stamp collecting. A good review does not just summarize the literature, but discusses it critically, identifies methodological problems, and points out research gaps [19] . After having read a review of the literature, a reader should have a rough idea of:

• the major achievements in the reviewed field,
• the main areas of debate, and
• the outstanding research questions.

It is challenging to achieve a successful review on all these fronts. A solution can be to involve a set of complementary coauthors: some people are excellent at mapping what has been achieved, some others are very good at identifying dark clouds on the horizon, and some have instead a knack at predicting where solutions are going to come from. If your journal club has exactly this sort of team, then you should definitely write a review of the literature! In addition to critical thinking, a literature review needs consistency, for example in the choice of passive vs. active voice and present vs. past tense.

Rule 7: Find a Logical Structure

Like a well-baked cake, a good review has a number of telling features: it is worth the reader's time, timely, systematic, well written, focused, and critical. It also needs a good structure. With reviews, the usual subdivision of research papers into introduction, methods, results, and discussion does not work or is rarely used. However, a general introduction of the context and, toward the end, a recapitulation of the main points covered and take-home messages make sense also in the case of reviews. For systematic reviews, there is a trend towards including information about how the literature was searched (database, keywords, time limits) [20] .

How can you organize the flow of the main body of the review so that the reader will be drawn into and guided through it? It is generally helpful to draw a conceptual scheme of the review, e.g., with mind-mapping techniques. Such diagrams can help recognize a logical way to order and link the various sections of a review [21] . This is the case not just at the writing stage, but also for readers if the diagram is included in the review as a figure. A careful selection of diagrams and figures relevant to the reviewed topic can be very helpful to structure the text too [22] .

Rule 8: Make Use of Feedback

Reviews of the literature are normally peer-reviewed in the same way as research papers, and rightly so [23] . As a rule, incorporating feedback from reviewers greatly helps improve a review draft. Having read the review with a fresh mind, reviewers may spot inaccuracies, inconsistencies, and ambiguities that had not been noticed by the writers due to rereading the typescript too many times. It is however advisable to reread the draft one more time before submission, as a last-minute correction of typos, leaps, and muddled sentences may enable the reviewers to focus on providing advice on the content rather than the form.

Feedback is vital to writing a good review, and should be sought from a variety of colleagues, so as to obtain a diversity of views on the draft. This may lead in some cases to conflicting views on the merits of the paper, and on how to improve it, but such a situation is better than the absence of feedback. A diversity of feedback perspectives on a literature review can help identify where the consensus view stands in the landscape of the current scientific understanding of an issue [24] .

Rule 9: Include Your Own Relevant Research, but Be Objective

In many cases, reviewers of the literature will have published studies relevant to the review they are writing. This could create a conflict of interest: how can reviewers report objectively on their own work [25] ? Some scientists may be overly enthusiastic about what they have published, and thus risk giving too much importance to their own findings in the review. However, bias could also occur in the other direction: some scientists may be unduly dismissive of their own achievements, so that they will tend to downplay their contribution (if any) to a field when reviewing it.

In general, a review of the literature should neither be a public relations brochure nor an exercise in competitive self-denial. If a reviewer is up to the job of producing a well-organized and methodical review, which flows well and provides a service to the readership, then it should be possible to be objective in reviewing one's own relevant findings. In reviews written by multiple authors, this may be achieved by assigning the review of the results of a coauthor to different coauthors.

Rule 10: Be Up-to-Date, but Do Not Forget Older Studies

Given the progressive acceleration in the publication of scientific papers, today's reviews of the literature need awareness not just of the overall direction and achievements of a field of inquiry, but also of the latest studies, so as not to become out-of-date before they have been published. Ideally, a literature review should not identify as a major research gap an issue that has just been addressed in a series of papers in press (the same applies, of course, to older, overlooked studies (“sleeping beauties” [26] )). This implies that literature reviewers would do well to keep an eye on electronic lists of papers in press, given that it can take months before these appear in scientific databases. Some reviews declare that they have scanned the literature up to a certain point in time, but given that peer review can be a rather lengthy process, a full search for newly appeared literature at the revision stage may be worthwhile. Assessing the contribution of papers that have just appeared is particularly challenging, because there is little perspective with which to gauge their significance and impact on further research and society.

Inevitably, new papers on the reviewed topic (including independently written literature reviews) will appear from all quarters after the review has been published, so that there may soon be the need for an updated review. But this is the nature of science [27] – [32] . I wish everybody good luck with writing a review of the literature.

Acknowledgments

Many thanks to M. Barbosa, K. Dehnen-Schmutz, T. Döring, D. Fontaneto, M. Garbelotto, O. Holdenrieder, M. Jeger, D. Lonsdale, A. MacLeod, P. Mills, M. Moslonka-Lefebvre, G. Stancanelli, P. Weisberg, and X. Xu for insights and discussions, and to P. Bourne, T. Matoni, and D. Smith for helpful comments on a previous draft.

• 1. Rapple C (2011) The role of the critical review article in alleviating information overload. Annual Reviews White Paper. Available: http://www.annualreviews.org/userimages/ContentEditor/1300384004941/Annual_Reviews_WhitePaper_Web_2011.pdf . Accessed May 2013.
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• 7. Budgen D, Brereton P (2006) Performing systematic literature reviews in software engineering. Proc 28th Int Conf Software Engineering, ACM New York, NY, USA, pp. 1051–1052. doi: https://doi.org/10.1145/1134285.1134500 .
• 16. Eco U (1977) Come si fa una tesi di laurea. Milan: Bompiani.
• 17. Hart C (1998) Doing a literature review: releasing the social science research imagination. London: SAGE.
• 21. Ridley D (2008) The literature review: a step-by-step guide for students. London: SAGE.

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Passive Voice: When to Use It and When to Avoid It

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What is passive voice?

In English, all sentences are in either “active” or “passive” voice:

active: Werner Heisenberg formulated the uncertainty principle in 1927. passive: The uncertainty principle was formulated by Werner Heisenberg in 1927.

In an active sentence, the person or thing responsible for the action in the sentence comes first. In a passive sentence, the person or thing acted on comes first, and the actor is added at the end, introduced with the preposition “by.” The passive form of the verb is signaled by a form of “to be”: in the sentence above, “was formulated” is in passive voice while “formulated” is in active.

In a passive sentence, we often omit the actor completely:

The uncertainty principle was formulated in 1927.

When do I use passive voice?

In some sentences, passive voice can be perfectly acceptable. You might use it in the following cases:

The cave paintings of Lascaux were made in the Upper Old Stone Age. [We don’t know who made them.]

An experimental solar power plant will be built in the Australian desert. [We are not interested in who is building it.]

Mistakes were made. [Common in bureaucratic writing!]

Rules are made to be broken. [By whomever, whenever.]

Insulin was first discovered in 1921 by researchers at the University of Toronto. It is still the only treatment available for diabetes.

The sodium hydroxide was dissolved in water. This solution was then titrated with hydrochloric acid.

In these sentences you can count on your reader to know that you are the one who did the dissolving and the titrating. The passive voice places the emphasis on your experiment rather than on you.

Note: Over the past several years, there has been a movement within many science disciplines away from passive voice. Scientists often now prefer active voice in most parts of their published reports, even occasionally using the subject “we” in the Materials and Methods section. Check with your instructor or TA whether you can use the first person “I” or “we” in your lab reports to help avoid the passive.

When should I avoid passive voice?

Passive sentences can get you into trouble in academic writing because they can be vague about who is responsible for the action:

Both Othello and Iago desire Desdemona. She is courted. [Who courts Desdemona? Othello? Iago? Both of them?]

Academic writing often focuses on differences between the ideas of different researchers, or between your own ideas and those of the researchers you are discussing. Too many passive sentences can create confusion:

Research has been done to discredit this theory. [Who did the research? You? Your professor? Another author?]

Some students use passive sentences to hide holes in their research:

The telephone was invented in the nineteenth century. [I couldn’t find out who invented the telephone!]

Finally, passive sentences often sound wordy and indirect. They can make the reader work unnecessarily hard. And since they are usually longer than active sentences, passive sentences take up precious room in your paper:

Since the car was being driven by Michael at the time of the accident, the damages should be paid for by him.

Weeding out passive sentences

If you now use a lot of passive sentences, you may not be able to catch all of the problematic cases in your first draft. But you can still go back through your essay hunting specifically for passive sentences. At first, you may want to ask for help from a writing instructor. The grammar checker in your word processor can help spot passive sentences, though grammar checkers should always be used with extreme caution since they can easily mislead you. To spot passive sentences, look for a form of the verb to be in your sentence, with the actor either missing or introduced after the verb using the word “by”:

Poland was invaded in 1939, thus initiating the Second World War. Genetic information is encoded by DNA. The possibility of cold fusion has been examined for many years.

Try turning each passive sentence you find into an active one. Start your new sentence with the actor. Sometimes you may find that need to do some extra research or thinking to figure out who the actor should be! You will likely find that your new sentence is stronger, shorter, and more precise:

Germany invaded Poland in 1939, thus initiating the Second World War. DNA encodes genetic information. Physicists have examined the possibility of cold fusion for many years.

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Using Active or Passive Voice in Research Papers

When to Use the Active or Passive Voice in Research Writing

One decision that gives pause to thousands of beginning researchers is whether to use the active or passive voice in their research papers. You may have been taught in school that you should always use the active voice, especially when giving speeches and when writing fiction or persuasive essays, as it emphasizes the subject and makes your sentences leaner and stronger.

While this rule generally applies to research writing, there are some definite differences in application–this accounts for why there are so many sentences in scientific journal articles using the passive voice construction. In fact, applying only  one  type of voice construction can make a paper awkward to read and difficult to comprehend, and it might even confuse the reader about which parts of the study or a given passage are most important. So when should an author choose the passive voice over the active voice and what is the difference between the two?

Differences Between the  Active  and the  Passive Voice

In general, the active voice emphasizes the  agent  of the action—that is, the  person or object performing the action .

Example: “ We   arranged  the sample groups.”

The subject pronoun “we” leads the sentence, setting off its importance in the action and leading right into the action taken against the object, “the sample groups.” Using this construction doesn’t necessarily imply that “the sample groups” is unimportant, but it does place special emphasis on the agent of the action.

The passive voice, on the other hand, emphasizes the  person or object receiving the action.

Example:  “ Sample groups   were arranged  (by us/by the researchers).”

In this example, “sample groups” stands out as the most important element in the sentence, and indeed it should since we are able to omit the agent entirely—adding “by us” or “by the researchers” seems redundant as the researchers are necessarily the ones carrying out the operations of a study. Also, note that by eliminating the agent we have also decreased the word count, which makes the passive construction leaner than the active voice in this case.

Since active-voice constructions are usually stronger, clearer, more direct, and often more concise than their passive-voice counterparts, most style guides advise scientific and clinical authors to favor the active voice in their research writing.

However, this is not a command to silence the passive voice entirely. In fact, scientific manuscripts have increasingly favored passive-voice construction in the past couple of decades. Whether the reasons for this are practical or because it is simply more fashionable today to use the passive voice, there are good reasons to include this construction to gain a balanced perspective in your writing.

Sticking with the conventional wisdom that we should use the  active voice  as often as possible, when exactly should we opt for the passive? Here are three circumstances in which using the passive voice can be a good decision.

1) When the agent of the action is unimportant, unknown, or obvious to readers

Choose the passive voice when the agent of the action is unknown or unimportant to the action being discussed, or when it is quite clear who is performing the action. In some cases, you may identify the agent using a “by” clause, but it is often unnecessary to add this information.

Examples of active and passive voice:

“Over 20,000 patients  are diagnosed  with diabetes each year (by doctors) in the United States.” “Encyclopedias  have been written  (by scribes and scholars) throughout history.” “ Carcharodon carcharias   has been studied  (by scientists) more extensively than almost any other species of shark.”

In the first example, naming the agent of diagnosis is redundant, as doctors are almost universally the ones who diagnose diseases. In the second example, the author assumes the reader will not be interested in the authors (this decision of course depends on the focus of the study) or perhaps the authors are unknown; the agent may be added in case this information is known and is somewhat important to the statement. In the third example, the agent is fairly obvious, as scientists are the ones tasked with studying species of animals.

2) When the object or action itself is more important than the agent performing the action

In research writing, the study is clearly of greater importance than the researcher undertaking the study (unless that researcher happens to be someone as renowned as Stephen Hawking), and thus the passive voice is more often employed. This object/action focus can commonly be seen in the  Methods  section, in which an author writes about what he or she did (or rather,  “what was done”),  mostly using the passive voice since the topics here are generally the research methods, materials, and procedures.

“Frozen embryos  were stored  in a cryogenic tank for two weeks.” “The extract from sample A  was added  to sample B to create a mixture.” “The results  were assessed  using a Chi-square statistic.”

The sentences might be written in the active voice like so:

“We  stored  the embryos in a cryogenic tank for two weeks.” “We  added  the extract from sample A to sample B to create a mixture.” “Our team  assessed  the results using a Chi-square statistic.”

What would be the net benefit of using the active voice here? In none of these examples would the active voice improve the sentences by shortening them or by clarifying the focus of the action. The length of each active sentence is the same as its passive voice counterpart, and the sentences in the active voice actually redirect the focus to the  agent —“we” or “our team”—which does not seem to be the most important element in any of these examples. The active-voice constructions are admittedly a bit stronger and livelier, but they seem more fitting for a short story or anecdote than for an explanation of actions carried out in the course of a scientific study.

Another benefit of using the passive voice in the Methods section (in addition to some other parts of the research paper) is that it varies the structure and cadence of your sentences while maintaining an emphasis on the actual work. One can see how a paper becomes more readable when there isn’t constant emphasis on only one part of a sentence.

In the  Methods  and other sections of the manuscript, use the passive voice to redirect focus to the work being done—the object of the action or the action itself. When editing a manuscript , note this distinction in voice usage between the Methods section and other sections, as it is a common one in research writing.

3) When the recipient of the action is the topic of your sentence

It is sometimes necessary to use the passive voice to place the  most important information  at the beginning. By placing an item at the  beginning  of a sentence, you are putting it in the “topic position” (or “subject position”), indicating that it is the central element of your sentence.

Similarly, by placing a word at the  very end  of your sentence, you put it in the “stress position,” which is often used for words or phrases that modify or qualify the primary focus of your sentence. You can place words in these positions using passive or active constructions.

Active voice: “Scientists once  classified  slime molds as fungi, but they no longer  classify  them as part of that particular kingdom.” Passive voice: “Slime molds  were  once  classified  as fungi but  are  no longer  considered  to be part of that particular kingdom.”

In the first example, “scientists” occupies the topic position, and “part of that particular kingdom” is in the stress position. What might this ordering indicate to the reader? First, it shows that “scientists” is perhaps the main focus (or at least an important element) of this information. Second, by putting “part of that particular kingdom” at the end of the sentence, the author seems to be telling the reader that this qualifying information is also essential to understanding this information.

How might this information be interpreted differently in passive-voice construction? The main difference here is that “slime molds” are placed in the topic position, indicating that they are the primary focus of this information.

Privileging One Element Over Another in a Sentence

Which voice you use and how you order your sentence elements can make a big difference in establishing the importance of one element over another, especially when both of these are important to your study and neither involve the researcher.

In the following examples, there are at least two elements that the study focuses on. Reordering these by changing the voice makes the importance of these positions quite clear.

Active voice: “These amoeba coalesce into a multicellular, slug-like coordinated creature that  grows  into a fruiting body.” Passive voice: “This multicellular, slug-like coordinated creature, which eventually  grows  a fruiting body, is created by coalescing amoeba.”

In both of these sentences, the “amoeba” and the “multicellular, slug-like coordinated creature” are central; they seem to be essentially two parts of one process. This  process  is demonstrated through the active construction, which explains the life-cycle chronologically and therefore places emphasis on both elements (both agents) equally: “amoeba” and “fruiting body” (in the topic and stress position respectively) are at the beginning and end of this sentence and the particular part of the life cycle, with the information in the middle representing the transition between the two.

However, in the passive-voice construction, the “multicellular, slug-like coordinated creature” is in the topic position, the “amoeba” in the stress position, and the “fruiting body” in the middle is described (using a relative clause) as an outgrowth of this “creature.” This ordering completely shifts the focus of the sentence to the multicellular creature itself, with the other elements acting as supporting information. But because “amoeba” is still included in the sentence and is in the stress position, the author clearly wants to show its importance.

Combining the Active and Passive Constructions in a Sequence of Sentences

Whether introducing the purpose of your study in the  Introduction  section or suggesting further applications or studies in the  Discussion  and  Conclusion , you should try to combine conciseness and clarity of intention to create a logically cohesive structure. This can be done by combining passive and active constructions.

One way to achieve this is to create a structure that “connects backwards”—the final sentence in your paragraph or short sequence of sentences explains the purpose of the first sentence. Let’s see how this might work in action in the  Introduction  section.

Example of three cohesive sentences ( active—passive—passive ):

[Excerpt from “A Possible Correction of the Face Inversion Effect: A Methodological Commentary” (Rakover, Sam and Cahlon, Baruch)] “The present commentary concerns the face/object (UI) effect. This effect can be explained by appeal to either innate or learning factors. However, this effect  can  also be influenced by another factor, the ‘baseline-level,’ which is the focus of the present commentary.”

These three lines occur in sequence within the paper’s  Introduction  section. The first sentence clearly and directly explains the problem of the study (“the face/object (UI) effect”) using the active voice, setting the reader up for a further explanation to follow.

The second sentence, written in the passive voice, explores some potential directions from which this problem can be approached.

And the third sentence unites the two ideas, or “synthesizes” them, using a passive-voice construction. This third sentence has a parallel structure to the second and unites the problem and the proposed explanations using the word “influence” as a unifying action.

By focusing on the topic (“the effect”), the author can create a cohesive structure that uses sentences in both the active and passive voice. Such a passage flows naturally and is more comprehensible and enjoyable for the reader than separated sentences using the same voice construction.

Active and Passive Voice Guidelines

There are several good reasons to vary your sentences between active and passive voice:

• To place emphasis on the most important element of the sentence
• To cut down on word count (sometimes using active, sometimes using passive)
• To make your paper easier for the reader by creating variations in cadence and syntax

As a rule of thumb,  choose the active voice whenever possible.

Choose the passive voice  when there is good reason to do so. Consider passive voice when:

• The agent is unknown, unimportant, or obvious to the reader
• The agent is less important than the  action  of the sentence
• The agent is less important than the  topic  of the sentence
• One topic (among several) has greater importance

To ensure that your voice constructions follow style guidelines, as well as grammar rules, be sure to get paper proofreading services from a reputable English editing company like Wordvice.

Academic Resources:

• Springer.com.  “Stress Position”  https://www.springer.com/gp/authors-editors/authorandreviewertutorials/writinginenglish/stress-position/10252690
• Gopen GD, Swan JA. The science of scientific writing.  Am Scientist.  1990;78:550-558.
• Rakover, S., & CAHLON, B. (2014). A Possible Correction of the Face Inversion Effect: A Methodological Commentary.  The American Journal of Psychology,   127 (3), 303-311. doi:10.5406/amerjpsyc.127.3.0303 Website:  https://www.jstor.org/stable/10.5406/amerjpsyc.127.3.0303?seq=1#page_scan_tab_contents
• Wordvice  Blog: “Which Tenses to Use in Your Research Paper.”  https://blog.wordvice.com/video-which-verb-tenses-should-i-use-in-a-research-paper/
• Wordvice  Blog: “How to Choose the Best Title for Your Manuscript.”  https://blog.wordvice.com/best-title-for-journal-manuscript/
• Wordvice YouTube Channel:  “ How to Create a Title for Your Research Paper .”
• Wordvice Blog:  “Choosing the Best Keywords for Your Paper.”  https://blog.wordvice.com/choosing-research-paper-keywords/
• Wordvice YouTube Channel:  “Parts of a Research Paper.”  https://www.youtube.com/watch?v=aO6ipI-d2fw
• ScienceDocs  Inc. Blog: “5 Common Mistakes to Avoid When Writing a Discussion.”  https://www.sciencedocs.com/writing-a-research-paper-discussion/ 

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Scholarly Voice: Active and Passive Voice

Active and passive voice.

Active voice and passive voice are grammatical constructions that communicate certain information about an action. Specifically, APA explains that voice shows relationships between the verb and the subject and/or object (see APA 7, Section 4.13). Writers need to be intentional about voice in order to ensure clarity. Using active voice often improves clarity, while passive voice can help avoid unnecessary repetition.  

Active voice can help ensure clarity by making it clear to the reader who is taking action in the sentence. In addition, the active voice stresses that the actor (or grammatical subject) precedes the verb, again, putting emphasis on the subject. Passive voice construction leaves out the actor (subject) and focuses on the relationship between the verb and object.

The order of words in a sentence with active voice is subject, verb, object.

• Active voice example : I conducted a study of elementary school teachers.
• This sentence structure puts the emphasis of the sentence on the subject, clarifying who conducted the study. 
• Passive voice example : A study was conducted of elementary school teachers.
• In this sentence, it is not clear who conducted this study. 

Generally, in scholarly writing, with its emphasis on precision and clarity, the active voice is preferred. However, the passive voice is acceptable in some instances, for example:

• if the reader is aware of who the actor is;
• in expository writing, where the goal of the discussion is to provide background, context, or an in-depth explanation;
• if the writer wants to focus on the object or the implications of the actor’s action; or
• to vary sentence structure.  

Also, much like for anthropomorphism , different writing styles have different preferences. So, though you may see the passive voice used heavily in articles that you read for your courses and study, it does not mean that APA style advocates the same usage.

Examples of Writing in the Active Voice

Here are some examples of scholarly writing in the active voice:

• This is active voice because the subject in the sentence precedes the verb, clearly indicating who (I) will take the action (present).

Example : Teachers conducted a pilot study addressing the validity of the TAKS exam.

• Similarly, teachers (subject) clearly took the action (conducted) in this sentence.

Recognizing the Passive Voice

According to APA, writers should select verb tenses and voice carefully. Consider these examples to help determine which form of the verb is most appropriate:

Example : A study was conducted of job satisfaction and turnover.

• Here, it is not clear who did the conducting. In this case, if the context of the paragraph does not clarify who did the action, the writer should revise this sentence to clarify who conducted the study. 

Example : I conducted a study of job satisfaction and turnover.

• This revised sentence clearly indicates the action taker. Using “I” to identify the writer’s role in the research process is often a solution to the passive voice and is encouraged by APA style (see APA 7, Section 4.16).

Using the past tense of the verb “to be” and the past participle of a verb together is often an indication of the passive voice. Here are some signs to look for in your paper:

• Example : This study was conducted.
• Example : Findings were distributed.

Another indication of passive voice is when the verb precedes the actor in the sentence. Even if the action taker is clearly identified in a passive voice construction, the sentence is usually wordier. Making the actor the grammatical subject that comes before the verb helps to streamline the sentence.

• Issue : Though the verb and the actor (action taker) are clearly identified here, to improve clarity and word economy, the writer could place that actor, Rogers, before the verb.
• More concise active voice revision : Rogers (2016) conducted a study on nursing and turnover.  
• Issue : Here, the actor follows the verb, which reduces emphasis and clarity.
• This revised sentence is in the active voice and makes the actor the subject of the sentence.

Intentional Use of the Passive Voice

Sometimes, even in scholarly writing, the passive voice may be used intentionally and strategically. A writer may intentionally include the subject later in the sentence so as to reduce the emphasis and/or importance of the subject in the sentence. See the following examples of intentional passive voice to indicate emphasis:

Example : Schools not meeting AYP for 2 consecutive years will be placed on a “needs improvement” list by the State’s Department of Education.

• Here, all actors taking actions are identified, but this is in the passive voice as the State’s Department of Education is the actor doing the placing, but this verb precedes the actor. This may be an intentional use of the passive voice, to highlight schools not meeting AYP.
• To write this in the active voice, it would be phrased: “The State’s Department of Education will place schools not meeting AYP for 2 consecutive years on a “needs improvement” list. This sentence places the focus on the State’s Department of Education, not the schools.

Example : Participants in the study were incentivized with a $5 coffee gift card, which I gave them upon completion of their interview.

• As the writer and researcher, I may want to vary my sentence structure in order to avoid beginning several sentences with “I provided…” This example is written in the passive voice, but the meaning is clear.

Using Passive Voice in Scholarly Writing

As noted before, passive voice is allowed in APA style and can be quite appropriate, especially when writing about methods and data collection. However, students often overuse the passive voice in their writing, which means their emphasis in the sentence is not on the action taker. Their writing is also at risk of being repetitive. Consider the following paragraph in which the passive voice is used in each sentence:

A survey was administered . Using a convenience sample, 68 teachers were invited to participate in the survey by emailing them an invitation. E-mail addresses of teachers who fit the requirements for participation were provided by the principal of the school . The teachers were e-mailed an information sheet and a consent form. Responses were collected from 45 teachers… As you can see, the reader has no idea who is performing these actions, which makes the research process unclear. This is at odds with the goal of the methods discussion, which is to be clear and succinct regarding the process of data collection and analysis.

However, if translated entirely to the active voice, clearly indicating the researcher’s role, “I” becomes redundant and repetitive, interrupting the flow of the paragraph:

In this study, I administered a survey. I created a convenience sample of 68 teachers. I invited them to participate in the survey by emailing them an invitation. I obtained e-mail addresses from the principal of the school… “I” is quite redundant here and repetitive for the reader.

The Walden Writing Center suggests that students use “I” in the first sentence of the paragraph . Then, as long as it is clear to the reader that the student (writer) is the actor in the remaining sentences, use the active and passive voices appropriately to achieve precision and clarity (where applicable):

In this study, I administered a survey using a convenience sample. Sixty-eight teachers were invited to participate in the survey. The principal of the school provided me with the e-mail addresses of teachers who fit the requirements for participation. I e-mailed the teachers an information sheet and a consent form. A total of 45 teachers responded …

The use of the passive voice is complicated and requires careful attention and skill. There are no hard-and-fast rules. Using these guidelines, however, should help writers be clearer and more engaging in their writing, as well as achieving the intended purposes.

Remember, use voice strategically. APA recommends the active voice for clarity. However, the passive voice may be used, with intention, to remove the emphasis on the subject and also as a method for varying sentence structure. So, generally write in the active voice, but consider some of the above examples and some uses of the passive voice that may be useful to implement in your writing. Just be sure that the reader is always aware of who is taking the action of the verb.

• For more practice, try our Clarifying the Actor module .

Related Resources

• Principles of Writing: Active and Passive Voice (blog post) APA Style Blog post.

Didn't find what you need? Email us at [email protected] .

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• v.9(7); 2013 Jul

Ten Simple Rules for Writing a Literature Review

Marco pautasso.

1 Centre for Functional and Evolutionary Ecology (CEFE), CNRS, Montpellier, France

2 Centre for Biodiversity Synthesis and Analysis (CESAB), FRB, Aix-en-Provence, France

Literature reviews are in great demand in most scientific fields. Their need stems from the ever-increasing output of scientific publications [1] . For example, compared to 1991, in 2008 three, eight, and forty times more papers were indexed in Web of Science on malaria, obesity, and biodiversity, respectively [2] . Given such mountains of papers, scientists cannot be expected to examine in detail every single new paper relevant to their interests [3] . Thus, it is both advantageous and necessary to rely on regular summaries of the recent literature. Although recognition for scientists mainly comes from primary research, timely literature reviews can lead to new synthetic insights and are often widely read [4] . For such summaries to be useful, however, they need to be compiled in a professional way [5] .

When starting from scratch, reviewing the literature can require a titanic amount of work. That is why researchers who have spent their career working on a certain research issue are in a perfect position to review that literature. Some graduate schools are now offering courses in reviewing the literature, given that most research students start their project by producing an overview of what has already been done on their research issue [6] . However, it is likely that most scientists have not thought in detail about how to approach and carry out a literature review.

Reviewing the literature requires the ability to juggle multiple tasks, from finding and evaluating relevant material to synthesising information from various sources, from critical thinking to paraphrasing, evaluating, and citation skills [7] . In this contribution, I share ten simple rules I learned working on about 25 literature reviews as a PhD and postdoctoral student. Ideas and insights also come from discussions with coauthors and colleagues, as well as feedback from reviewers and editors.

Rule 1: Define a Topic and Audience

How to choose which topic to review? There are so many issues in contemporary science that you could spend a lifetime of attending conferences and reading the literature just pondering what to review. On the one hand, if you take several years to choose, several other people may have had the same idea in the meantime. On the other hand, only a well-considered topic is likely to lead to a brilliant literature review [8] . The topic must at least be:

• interesting to you (ideally, you should have come across a series of recent papers related to your line of work that call for a critical summary),
• an important aspect of the field (so that many readers will be interested in the review and there will be enough material to write it), and
• a well-defined issue (otherwise you could potentially include thousands of publications, which would make the review unhelpful).

Ideas for potential reviews may come from papers providing lists of key research questions to be answered [9] , but also from serendipitous moments during desultory reading and discussions. In addition to choosing your topic, you should also select a target audience. In many cases, the topic (e.g., web services in computational biology) will automatically define an audience (e.g., computational biologists), but that same topic may also be of interest to neighbouring fields (e.g., computer science, biology, etc.).

Rule 2: Search and Re-search the Literature

After having chosen your topic and audience, start by checking the literature and downloading relevant papers. Five pieces of advice here:

• keep track of the search items you use (so that your search can be replicated [10] ),
• keep a list of papers whose pdfs you cannot access immediately (so as to retrieve them later with alternative strategies),
• use a paper management system (e.g., Mendeley, Papers, Qiqqa, Sente),
• define early in the process some criteria for exclusion of irrelevant papers (these criteria can then be described in the review to help define its scope), and
• do not just look for research papers in the area you wish to review, but also seek previous reviews.

The chances are high that someone will already have published a literature review ( Figure 1 ), if not exactly on the issue you are planning to tackle, at least on a related topic. If there are already a few or several reviews of the literature on your issue, my advice is not to give up, but to carry on with your own literature review,

The bottom-right situation (many literature reviews but few research papers) is not just a theoretical situation; it applies, for example, to the study of the impacts of climate change on plant diseases, where there appear to be more literature reviews than research studies [33] .

• discussing in your review the approaches, limitations, and conclusions of past reviews,
• trying to find a new angle that has not been covered adequately in the previous reviews, and
• incorporating new material that has inevitably accumulated since their appearance.

When searching the literature for pertinent papers and reviews, the usual rules apply:

• be thorough,
• use different keywords and database sources (e.g., DBLP, Google Scholar, ISI Proceedings, JSTOR Search, Medline, Scopus, Web of Science), and
• look at who has cited past relevant papers and book chapters.

Rule 3: Take Notes While Reading

If you read the papers first, and only afterwards start writing the review, you will need a very good memory to remember who wrote what, and what your impressions and associations were while reading each single paper. My advice is, while reading, to start writing down interesting pieces of information, insights about how to organize the review, and thoughts on what to write. This way, by the time you have read the literature you selected, you will already have a rough draft of the review.

Of course, this draft will still need much rewriting, restructuring, and rethinking to obtain a text with a coherent argument [11] , but you will have avoided the danger posed by staring at a blank document. Be careful when taking notes to use quotation marks if you are provisionally copying verbatim from the literature. It is advisable then to reformulate such quotes with your own words in the final draft. It is important to be careful in noting the references already at this stage, so as to avoid misattributions. Using referencing software from the very beginning of your endeavour will save you time.

Rule 4: Choose the Type of Review You Wish to Write

After having taken notes while reading the literature, you will have a rough idea of the amount of material available for the review. This is probably a good time to decide whether to go for a mini- or a full review. Some journals are now favouring the publication of rather short reviews focusing on the last few years, with a limit on the number of words and citations. A mini-review is not necessarily a minor review: it may well attract more attention from busy readers, although it will inevitably simplify some issues and leave out some relevant material due to space limitations. A full review will have the advantage of more freedom to cover in detail the complexities of a particular scientific development, but may then be left in the pile of the very important papers “to be read” by readers with little time to spare for major monographs.

There is probably a continuum between mini- and full reviews. The same point applies to the dichotomy of descriptive vs. integrative reviews. While descriptive reviews focus on the methodology, findings, and interpretation of each reviewed study, integrative reviews attempt to find common ideas and concepts from the reviewed material [12] . A similar distinction exists between narrative and systematic reviews: while narrative reviews are qualitative, systematic reviews attempt to test a hypothesis based on the published evidence, which is gathered using a predefined protocol to reduce bias [13] , [14] . When systematic reviews analyse quantitative results in a quantitative way, they become meta-analyses. The choice between different review types will have to be made on a case-by-case basis, depending not just on the nature of the material found and the preferences of the target journal(s), but also on the time available to write the review and the number of coauthors [15] .

Rule 5: Keep the Review Focused, but Make It of Broad Interest

Whether your plan is to write a mini- or a full review, it is good advice to keep it focused 16 , 17 . Including material just for the sake of it can easily lead to reviews that are trying to do too many things at once. The need to keep a review focused can be problematic for interdisciplinary reviews, where the aim is to bridge the gap between fields [18] . If you are writing a review on, for example, how epidemiological approaches are used in modelling the spread of ideas, you may be inclined to include material from both parent fields, epidemiology and the study of cultural diffusion. This may be necessary to some extent, but in this case a focused review would only deal in detail with those studies at the interface between epidemiology and the spread of ideas.

While focus is an important feature of a successful review, this requirement has to be balanced with the need to make the review relevant to a broad audience. This square may be circled by discussing the wider implications of the reviewed topic for other disciplines.

Rule 6: Be Critical and Consistent

Reviewing the literature is not stamp collecting. A good review does not just summarize the literature, but discusses it critically, identifies methodological problems, and points out research gaps [19] . After having read a review of the literature, a reader should have a rough idea of:

• the major achievements in the reviewed field,
• the main areas of debate, and
• the outstanding research questions.

It is challenging to achieve a successful review on all these fronts. A solution can be to involve a set of complementary coauthors: some people are excellent at mapping what has been achieved, some others are very good at identifying dark clouds on the horizon, and some have instead a knack at predicting where solutions are going to come from. If your journal club has exactly this sort of team, then you should definitely write a review of the literature! In addition to critical thinking, a literature review needs consistency, for example in the choice of passive vs. active voice and present vs. past tense.

Rule 7: Find a Logical Structure

Like a well-baked cake, a good review has a number of telling features: it is worth the reader's time, timely, systematic, well written, focused, and critical. It also needs a good structure. With reviews, the usual subdivision of research papers into introduction, methods, results, and discussion does not work or is rarely used. However, a general introduction of the context and, toward the end, a recapitulation of the main points covered and take-home messages make sense also in the case of reviews. For systematic reviews, there is a trend towards including information about how the literature was searched (database, keywords, time limits) [20] .

How can you organize the flow of the main body of the review so that the reader will be drawn into and guided through it? It is generally helpful to draw a conceptual scheme of the review, e.g., with mind-mapping techniques. Such diagrams can help recognize a logical way to order and link the various sections of a review [21] . This is the case not just at the writing stage, but also for readers if the diagram is included in the review as a figure. A careful selection of diagrams and figures relevant to the reviewed topic can be very helpful to structure the text too [22] .

Rule 8: Make Use of Feedback

Reviews of the literature are normally peer-reviewed in the same way as research papers, and rightly so [23] . As a rule, incorporating feedback from reviewers greatly helps improve a review draft. Having read the review with a fresh mind, reviewers may spot inaccuracies, inconsistencies, and ambiguities that had not been noticed by the writers due to rereading the typescript too many times. It is however advisable to reread the draft one more time before submission, as a last-minute correction of typos, leaps, and muddled sentences may enable the reviewers to focus on providing advice on the content rather than the form.

Feedback is vital to writing a good review, and should be sought from a variety of colleagues, so as to obtain a diversity of views on the draft. This may lead in some cases to conflicting views on the merits of the paper, and on how to improve it, but such a situation is better than the absence of feedback. A diversity of feedback perspectives on a literature review can help identify where the consensus view stands in the landscape of the current scientific understanding of an issue [24] .

Rule 9: Include Your Own Relevant Research, but Be Objective

In many cases, reviewers of the literature will have published studies relevant to the review they are writing. This could create a conflict of interest: how can reviewers report objectively on their own work [25] ? Some scientists may be overly enthusiastic about what they have published, and thus risk giving too much importance to their own findings in the review. However, bias could also occur in the other direction: some scientists may be unduly dismissive of their own achievements, so that they will tend to downplay their contribution (if any) to a field when reviewing it.

In general, a review of the literature should neither be a public relations brochure nor an exercise in competitive self-denial. If a reviewer is up to the job of producing a well-organized and methodical review, which flows well and provides a service to the readership, then it should be possible to be objective in reviewing one's own relevant findings. In reviews written by multiple authors, this may be achieved by assigning the review of the results of a coauthor to different coauthors.

Rule 10: Be Up-to-Date, but Do Not Forget Older Studies

Given the progressive acceleration in the publication of scientific papers, today's reviews of the literature need awareness not just of the overall direction and achievements of a field of inquiry, but also of the latest studies, so as not to become out-of-date before they have been published. Ideally, a literature review should not identify as a major research gap an issue that has just been addressed in a series of papers in press (the same applies, of course, to older, overlooked studies (“sleeping beauties” [26] )). This implies that literature reviewers would do well to keep an eye on electronic lists of papers in press, given that it can take months before these appear in scientific databases. Some reviews declare that they have scanned the literature up to a certain point in time, but given that peer review can be a rather lengthy process, a full search for newly appeared literature at the revision stage may be worthwhile. Assessing the contribution of papers that have just appeared is particularly challenging, because there is little perspective with which to gauge their significance and impact on further research and society.

Inevitably, new papers on the reviewed topic (including independently written literature reviews) will appear from all quarters after the review has been published, so that there may soon be the need for an updated review. But this is the nature of science [27] – [32] . I wish everybody good luck with writing a review of the literature.

Acknowledgments

Many thanks to M. Barbosa, K. Dehnen-Schmutz, T. Döring, D. Fontaneto, M. Garbelotto, O. Holdenrieder, M. Jeger, D. Lonsdale, A. MacLeod, P. Mills, M. Moslonka-Lefebvre, G. Stancanelli, P. Weisberg, and X. Xu for insights and discussions, and to P. Bourne, T. Matoni, and D. Smith for helpful comments on a previous draft.

Funding Statement

This work was funded by the French Foundation for Research on Biodiversity (FRB) through its Centre for Synthesis and Analysis of Biodiversity data (CESAB), as part of the NETSEED research project. The funders had no role in the preparation of the manuscript.

Active and Passive Voice

Voice describes the relationship between a verb and the subject and object associated with it.

• Active voice: the subject of a sentence is followed by the verb and then the object of the verb (e.g., “the children ate the cookies”).
• Passive voic e: the object of the verb is followed by the verb (usually a form of “to be” + past participle + the word “by”) and then the subject (e.g., “the cookies were eaten by the children”). If the subject is omitted (e.g., “the cookies were eaten”), it may result in confusion about who performed the action (did the children eat the cookies, or was it the dog?).

Both the active and the passive voice are permitted in APA Style. However, writers often overuse the passive voice.

• Use the active voice as much as possible to create direct, clear, and concise sentences, especially when you are writing about the actions of people.
• Use the passive voice when it is more important to focus on the recipient of an action than on who performed the action, such as when describing an experimental setup.

Active and passive voice are covered in the seventh edition APA Style manuals in the Publication Manual Section 4.13 and the Concise Guide Section 2.13

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Read insights from a recent high school graduate about the value of learning APA Style in high school.

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Learn why you should use APA Style based on your assignment type and/or academic discipline in our latest YouTube video.

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Data about college degrees awarded by field of study and what writing style is used in each.

Check your tone: Keeping it professional

When writing an APA Style paper, present ideas in a clear and straightforward manner. In this kind of scholarly writing, keep a professional tone.

The “no second-person” myth

Many writers believe the “no second-person” myth, which is that there is an APA Style guideline against using second-person pronouns such as “you” or “your.” On the contrary, you can use second-person pronouns in APA Style writing.

APA Style JARS for high school students

In this post, we provide an overview of APA Style JARS and resources that can be shared with high school students who want to learn more about effective communication in scholarly research.

Key takeaways from the Psi Chi webinar So You Need to Write a Literature Review

This blog post describes key tasks in writing an effective literature review and provides strategies for approaching those tasks.

The “no first-person” myth

Whether expressing your own views or actions or the views or actions of yourself and fellow authors, use the pronouns “I” and “we.”

The “outdated sources” myth

The “outdated sources” myth is that sources must have been published recently, such as the last 5 to 10 years. There is no timeliness requirement in APA Style.

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The APA Style Journal Article Reporting Standards (APA Style JARS) have been added to the EQUATOR Network. The network aims to promote accuracy and quality in reporting of research.

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Navigating the not-so-hidden treasures of the APA Style website

This post links directly to APA Style topics of interest that users may not even know exist on the website.

Welcome, singular “they”

This blog post provides insight into how this change came about and provides a forum for questions and feedback.

How and When to Use Active or Passive Voice in Research Papers

Many young researchers are unsure about when and where to use active or passive voice in research papers. In fact, once you are sure about what to include in your research article, the next big question usually is how to include this information and which writing voice to use.  

Being uncertain about whether to use the active or passive voice in research papers is actually quite common. The simple answer is that usage and preference of one over the other is arbitrary and depends on the point that you, the researcher, are trying to make 1 . Balance is crucial here, though; sticking to just one voice structure can not only make the article boring but also ambiguous at times. As a result, the reader is left unsure of the authors’ intended message and which section to focus on. 

You might be wondering at this point what the difference between active and passive voice is and why it matters so much when only the research should be of concern. It matters because choosing the right writing style is key to convey your ideas in your research paper in a clear, succinct, and convincing manner.

To make it easier, we answer the most frequently asked questions in this article. 

Table of Contents

• What’s the difference between active and passive voice? 
• When should you use active or passive voice in research papers? 
• i) The introduction section 
• ii) The results section 
• ii) The methods section 

What’s the difference between active and passive voice?

When you use active voice in research papers, the agent—a person or object—doing the stated “action”—receives emphasis. 

E.g., CRISPR is a new gene editing tool that edits the DNA (Active)  

The use of CRISPR as the agent in this sentence serves to highlight the significance of CRISPR as a tool for gene editing. 

When you use passive voice in scientific writing, emphasis is given to the subject (person or object) receiving the action (of the verb). 

E.g., The DNA can be edited by a new gene editing tool, CRISPR (Passive)  

In this example, DNA is the object of the CRISPR action (editing). The author wants to draw attention to how the DNA can be edited by CRISPR. Simply put, the performer (CRISPR) is the main focus in the active voice, whereas the recipient (DNA) is the star of the show in the passive voice. 

When should you use active or passive voice in research papers ?

When you write a research paper, active or passive voice usage makes a significant difference to how your words are interpreted. The use of passive voice in research papers has traditionally been favored; however, in recent years, more journals have started to prefer the use of active voice in research papers. Journals like Science and Nature encourage researchers to use, whenever appropriate, active voice in research papers 2 . This is because scientific articles should be simple to read and comprehend, and most sentences written in the active voice are succinct, straightforward, and vigorous. It does not imply that sentences in the passive voice have no place in your research articles. Passive sentences are formal, impersonal, and occasionally even shorter, making them just as significant as active voice sentences if used in the right way. See how the passive voice can be shorter and more impersonal than the active voice in the following example. 

E.g., Researchers have created the first artificial vision system for both land and water (Active)  

In the above active sentence, the placement of the subject (researchers) at the beginning gives the impression that researchers are significant in this context. 

E.g., The first artificial vision system for both land and water has been created (Passive)  

The most important part of the passive sentence above is the construction of the first artificial vision system (action); information about the researchers (subject) is either universally true or unnecessary and can be omitted entirely. 

In contrast, using passive voice can occasionally lengthen and also complicate a sentence. See this example: 

E.g., The James Webb telescope finds a 13.5 billion-year-old galaxy in the universe (Active)  

E.g., A 13.5 billion-year-old galaxy in the universe was found by the James Webb telescope (Passive)  

In this example, the active voice sentence is clear and emphasizes the James Webb telescope as the agent that performs the action of identifying a galaxy. The sentence in passive voice emphasizes the newly discovered galaxy and is two words longer than in active voice. 

Which sections of the manuscript require which type of voice construction?

It is crucial to use both active and passive voice in research papers in order to keep your writing from sounding repetitive and unclear. The active voice is typically used in an article’s introduction, results, and discussion sections to simplify complex information 3 . See a few examples: 

i) The introduction section

E.g., Mild and moderate diseases of the upper respiratory tract in animals and humans are caused by the SARS-CoV-2, an enveloped RNA virus (Passive)  

E.g., SARS-CoV-2 is an enveloped RNA virus that causes mild and moderate diseases of the upper respiratory tract in animals and humans (Active)  

As seen in the above example, using active voice in the introduction is preferable as it is clear and concise. 

ii) The results section

E.g., No attempts were made to check the interactions of the proteins as it was beyond the scope of the present study (Passive)  

E.g., We did not check the interactions of the proteins as it was beyond the scope of the present study (Active)  

Active voice is usually preferred in the results section to emphasize the outcome (interactions of protein in this example); it is also used to highlight the role of the authors in making decisions. 

ii) The methods section

The total RNA was treated with DNAseI to remove the contaminating DNA for cDNA synthesis (Passive)  

We treated the total RNA with DNAseI to remove the contaminating DNA for cDNA synthesis (Active)  

The use of passive voice is preferred in the methods section, where the process itself is valued more highly than who is performing the process. 

The general rule is, therefore, to select the preferred voice while taking the statement’s clarity and the points you want to emphasize into consideration. Needless to say, a combination of both voices provides cadence and clarity to the writing. When in doubt, use active voice liberally when you need objectivity, and use passive voice when it is required. Use passive voice in academic writing when the performer is unimportant, obvious, or unknown; passive voice is also preferred when the process or action is more important than who did it (often the case in the method section). Hope these tips help you understand when to use active and passive voice in research papers, and you can slay your academic writing. 

1. Majumdar, K. How to effectively use active and passive voice in research writing. Editage Insights (2019) https://www.editage.com/insights/how-to-effectively-use-active-and-passive-voice-in-research-writing

2. Clear Science Writing: Active Voice or Passive Voice? http://www.biomedicaleditor.com/active-voice.html

3. Cerejo, C. Using the active and passive voice in research writing. Editage Insights (2013) https://www.editage.com/insights/using-the-active-and-passive-voice-in-research-writing

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Passive Voice

What this handout is about.

This handout will help you understand what the passive voice is, why many professors and writing instructors frown upon it, and how you can revise your paper to achieve greater clarity. Some things here may surprise you. We hope this handout will help you to understand the passive voice and allow you to make more informed choices as you write.

So what is the passive voice? First, let’s be clear on what the passive voice isn’t. Below, we’ll list some common myths about the passive voice:

1. Myth: Use of the passive voice constitutes a grammatical error.

Use of the passive voice is not a grammatical error. It’s a stylistic issue that pertains to clarity—that is, there are times when using the passive voice can prevent a reader from understanding what you mean.

2. Myth: Any use of “to be” (in any form) constitutes the passive voice.

The passive voice entails more than just using a being verb. Using “to be” can weaken the impact of your writing, but it is occasionally necessary and does not by itself constitute the passive voice.

3. Myth: The passive voice always avoids the first person; if something is in first person (“I” or “we”) it’s also in the active voice.

On the contrary, you can very easily use the passive voice in the first person. Here’s an example: “I was hit by the dodgeball.”

4. Myth: You should never use the passive voice.

While the passive voice can weaken the clarity of your writing, there are times when the passive voice is OK and even preferable.

5. Myth: I can rely on my grammar checker to catch the passive voice.

See Myth #1. Since the passive voice isn’t a grammar error, it’s not always caught. Typically, grammar checkers catch only a fraction of passive voice usage.

Do any of these misunderstandings sound familiar? If so, you’re not alone. That’s why we wrote this handout. It discusses how to recognize the passive voice, when you should avoid it, and when it’s OK.

Defining the passive voice

A passive construction occurs when you make the object of an action into the subject of a sentence. That is, whoever or whatever is performing the action is not the grammatical subject of the sentence. Take a look at this passive rephrasing of a familiar joke:

Why was the road crossed by the chicken?

Who is doing the action in this sentence? The chicken is the one doing the action in this sentence, but the chicken is not in the spot where you would expect the grammatical subject to be. Instead, the road is the grammatical subject. The more familiar phrasing (why did the chicken cross the road?) puts the actor in the subject position, the position of doing something—the chicken (the actor/doer) crosses the road (the object). We use active verbs to represent that “doing,” whether it be crossing roads, proposing ideas, making arguments, or invading houses (more on that shortly).

Once you know what to look for, passive constructions are easy to spot. Look for a form of “to be” (is, are, am, was, were, has been, have been, had been, will be, will have been, being) followed by a past participle. (The past participle is a form of the verb that typically, but not always, ends in “-ed.” Some exceptions to the “-ed” rule are words like “paid” (not “payed”) and “driven.” (not “drived”).

Here’s a sure-fire formula for identifying the passive voice:

form of “to be” + past participle = passive voice

For example:

The metropolis has been scorched by the dragon’s fiery breath.

When her house was invaded, Penelope had to think of ways to delay her remarriage.

Not every sentence that contains a form of “have” or “be” is passive! Forms of the word “have” can do several different things in English. For example, in the sentence “John has to study all afternoon,” “has” is not part of a past-tense verb. It’s a modal verb, like “must,” “can,” or “may”—these verbs tell how necessary it is to do something (compare “I have to study” versus “I may study”). And forms of “be” are not always passive, either—”be” can be the main verb of a sentence that describes a state of being, rather than an action. For example, the sentence “John is a good student” is not passive; “is” is simply describing John’s state of being. The moral of the story: don’t assume that any time you see a form of “have” and a form of “to be” together, you are looking at a passive sentence.

Need more help deciding whether a sentence is passive? Ask yourself whether there is an action going on in the sentence. If so, what is at the front of the sentence? Is it the person or thing that does the action? Or is it the person or thing that has the action done to it? In a passive sentence, the object of the action will be in the subject position at the front of the sentence. As discussed above, the sentence will also contain a form of be and a past participle. If the subject appears at all, it will usually be at the end of the sentence, often in a phrase that starts with “by.” Take a look at this example:

The fish was caught by the seagull.

If we ask ourselves whether there’s an action, the answer is yes: a fish is being caught. If we ask what’s at the front of the sentence, the actor or the object of the action, it’s the object: the fish, unfortunately for it, got caught, and there it is at the front of the sentence. The thing that did the catching—the seagull—is at the end, after “by.” There’s a form of be (was) and a past participle (caught). This sentence is passive.

Let’s briefly look at how to change passive constructions into active ones. You can usually just switch the word order, making the actor and subject one by putting the actor up front:

The dragon has scorched the metropolis with his fiery breath.

After suitors invaded her house, Penelope had to think of ways to delay her remarriage.

To repeat, the key to identifying the passive voice is to look for both a form of “to be” and a past participle, which usually, but not always, ends in “-ed.”

Clarity and meaning

The primary reason why your instructors frown on the passive voice is that they often have to guess what you mean. Sometimes, the confusion is minor. Let’s look again at that sentence from a student’s paper on Homer’s The Odyssey:

Like many passive constructions, this sentence lacks explicit reference to the actor—it doesn’t tell the reader who or what invaded Penelope’s house. The active voice clarifies things:

After suitors invaded Penelope’s house, she had to think of ways to fend them off.

Thus many instructors—the readers making sense of your writing—prefer that you use the active voice. They want you to specify who or what is doing the action. Compare the following two examples from an anthropology paper on a Laotian village to see if you agree.

(passive)  A new system of drug control laws was set up. (By whom?)

(active)  The Lao People’s Revolutionary Party set up a new system of drug control laws.

Here’s another example, from the same paper, that illustrates the lack of precision that can accompany the passive voice:

Gender training was conducted in six villages, thus affecting social relationships.

And a few pages later:

Plus, marketing links were being established.

In both paragraphs, the writer never specifies the actors for those two actions (Who did the gender training? Who established marketing links?). Thus the reader has trouble appreciating the dynamics of these social interactions, which depend upon the actors conducting and establishing these things.

The following example, once again from that paper on The Odyssey, typifies another instance where an instructor might desire more precision and clarity:

Although Penelope shares heroic characteristics with her husband, Odysseus, she is not considered a hero.

Who does not consider Penelope a hero? It’s difficult to tell, but the rest of that paragraph suggests that the student does not consider Penelope a hero (the topic of the paper). The reader might also conceivably think that the student is referring to critics, scholars, or modern readers of The Odyssey. One might argue that the meaning comes through here—the problem is merely stylistic. Yet style affects how your reader understands your argument and content. Awkward or unclear style prevents your reader from appreciating the ideas that are so clear to you when you write. Thus knowing how your reader might react enables you to make more effective choices when you revise. So after you identify instances of the passive, you should consider whether your use of the passive inhibits clear understanding of what you mean.

Summarizing history or literary plots with the passive voice: don’t be a lazy thinker or writer!

With the previous section in mind, you should also know that some instructors proclaim that the passive voice signals sloppy, lazy thinking. These instructors argue that writers who overuse the passive voice have not fully thought through what they are discussing and that this makes for imprecise arguments. Consider these sentences from papers on American history:

The working class was marginalized. African Americans were discriminated against. Women were not treated as equals.

Such sentences lack the precision and connection to context and causes that mark rigorous thinking. The reader learns little about the systems, conditions, human decisions, and contradictions that produced these groups’ experiences of oppression. And so the reader—the instructor—questions the writer’s understanding of these things.

It is especially important to be sure that your thesis statement is clear and precise, so think twice before using the passive voice in your thesis.

In papers where you discuss the work of an author—e.g., a historian or writer of literature—you can also strengthen your writing by not relying on the passive as a crutch when summarizing plots or arguments. Instead of writing:

It is argued that… or  Tom and Huck are portrayed as… or  And then the link between X and Y is made, showing that…

you can heighten the level of your analysis by explicitly connecting an author with these statements:

Anderson argues that… Twain portrays Tom and Huck as… Ishiguro draws a link between X and Y to show that…

By avoiding passive constructions in these situations, you can demonstrate a more thorough understanding of the material you discuss.

Scientific writing

All this advice works for papers in the humanities, you might note—but what about technical or scientific papers, including lab reports? Many instructors recommend or even require the passive voice in such writing. The rationale for using the passive voice in scientific writing is that it achieves “an objective tone”—for example, by avoiding the first person. To consider scientific writing, let’s break it up into two main types: lab reports and writing about a scientific topic or literature.

Lab reports

Although more and more scientific journals accept or even prefer first-person active voice (e.g., “then we sequenced the human genome”), some of your instructors may want you to remove yourself from your lab report by using the passive voice (e.g., “then the human genome was sequenced” rather than “then we sequenced the human genome”). Such advice particularly applies to the section on Materials and Methods, where a procedure “is followed.” (For a fuller discussion on writing lab reports, see our handout on writing lab reports .)

While you might employ the passive voice to retain objectivity, you can still use active constructions in some instances and retain your objective stance. Thus it’s useful to keep in mind the sort of active verbs you might use in lab reports. Examples include: support, indicate, suggest, correspond, challenge, yield, show.

Thus instead of writing:

A number of things are indicated by these results.

you could write:

These results indicate a number of things . or Further analysis showed/suggested/yielded…

Ultimately, you should find out your instructor’s preference regarding your use of the passive in lab reports.

Writing about scientific topics

In some assignments, rather than reporting the results of your own scientific work, you will be writing about the work of other scientists. Such assignments might include literature reviews and research reports on scientific topics. You have two main possible tasks in these assignments: reporting what other people have done (their research or experiments) or indicating general scientific knowledge (the body of knowledge coming out of others’ research). Often the two go together. In both instances, you can easily use active constructions even though you might be tempted by the passive—especially if you’re used to writing your own lab reports in the passive.

You decide: Which of these two examples is clearer?

(passive) Heart disease is considered the leading cause of death in the United States.

or (active)  Research points to heart disease as the leading cause of death in the United States.

Alternatively, you could write this sentence with human actors:

Researchers have concluded that heart disease is the leading cause of death in the United States.

The last two sentences illustrate a relationship that the first one lacks. The first example does not tell who or what leads us to accept this conclusion about heart disease.

Here’s one last example from a report that describes angioplasty. Which sounds better to you?

The balloon is positioned in an area of blockage and is inflated. or The surgeon positions the balloon in an area of blockage and inflates it.

You can improve your scientific writing by relying less on the passive. The advice we’ve given for papers on history or literature equally applies to papers in more “scientific” courses. No matter what field you’re writing in, when you use the passive voice, you risk conveying to your reader a sense of uncertainty and imprecision regarding your writing and thinking. The key is to know when your instructor wants you to use the passive voice. For a more general discussion of writing in the sciences , see our handout.

“Swindles and perversions”

Before we discuss a few instances when the passive might be preferable, we should mention one of the more political uses of the passive: to hide blame or obscure responsibility. You wouldn’t do this, but you can learn how to become a critic of those who exhibit what George Orwell included among the “swindles and perversions” of writing. For example:

Mistakes were made.

The Exxon Company accepts that a few gallons might have been spilled.

By becoming critically aware of how others use language to shape clarity and meaning, you can learn how better to revise your own work. Keep Orwell’s swindles and perversions in mind as you read other writers. Because it’s easy to leave the actor out of passive sentences, some people use the passive voice to avoid mentioning who is responsible for certain actions.

So when is it OK to use the passive?

Sometimes the passive voice is the best choice. Here are a few instances when the passive voice is quite useful:

1. To emphasize an object. Take a look at this example:

One hundred votes are required to pass the bill.

This passive sentence emphasizes the number of votes required. An active version of the sentence (“The bill requires 100 votes to pass”) would put the emphasis on the bill, which may be less dramatic.

2. To de-emphasize an unknown subject/actor. Consider this example:

Over 120 different contaminants have been dumped into the river.

If you don’t know who the actor is—in this case, if you don’t actually know who dumped all of those contaminants in the river—then you may need to write in the passive. But remember, if you do know the actor, and if the clarity and meaning of your writing would benefit from indicating him/her/it/them, then use an active construction. Yet consider the third case.

3. If your readers don’t need to know who’s responsible for the action.

Here’s where your choice can be difficult; some instances are less clear than others. Try to put yourself in your reader’s position to anticipate how they will react to the way you have phrased your thoughts. Here are two examples:

(passive)  Baby Sophia was delivered at 3:30 a.m. yesterday.

and (active)  Dr. Susan Jones delivered baby Sophia at 3:30 a.m. yesterday.

The first sentence might be more appropriate in a birth announcement sent to family and friends—they are not likely to know Dr. Jones and are much more interested in the “object”(the baby) than in the actor (the doctor). A hospital report of yesterday’s events might be more likely to focus on Dr. Jones’ role.

Summary of strategies

• Look for the passive voice: “to be” + a past participle (usually, but not always, ending in “-ed”)
• If you don’t see both components, move on.
• Does the sentence describe an action? If so, where is the actor? Is the he/she/they/it in the grammatical subject position (at the front of the sentence) or in the object position (at the end of the sentence, or missing entirely)?
• Does the sentence end with “by…”? Many passive sentences include the actor at the end of the sentence in a “by” phrase, like “The ball was hit by the player ” or “The shoe was chewed up by the dog .” “By” by itself isn’t a conclusive sign of the passive voice, but it can prompt you to take a closer look.
• Is the doer/actor indicated? Should you indicate him/her/them/it?
• Does it really matter who’s responsible for the action?
• Would your reader ask you to clarify a sentence because of an issue related to your use of the passive?
• Do you use a passive construction in your thesis statement?
• Do you use the passive as a crutch in summarizing a plot or history, or in describing something?
• Do you want to emphasize the object?
• If you decide that your sentence would be clearer in the active voice, switch the sentence around to make the subject and actor one. Put the actor (the one doing the action of the sentence) in front of the verb.

Towards active thinking and writing

We encourage you to keep these tips in mind as you revise. While you may be able to employ this advice as you write your first draft, that’s not necessarily always possible. In writing, clarity often comes when you revise, not on your first try. Don’t worry about the passive if that stress inhibits you in getting your ideas down on paper. But do look for it when you revise. Actively make choices about its proper place in your writing. There is nothing grammatically or otherwise “wrong” about using the passive voice. The key is to recognize when you should, when you shouldn’t, and when your instructor just doesn’t want you to. These choices are yours. We hope this handout helps you to make them.

Works consulted and suggested reading

We consulted these works while writing this handout. This is not a comprehensive list of resources on the handout’s topic, and we encourage you to do your own research to find additional publications. Please do not use this list as a model for the format of your own reference list, as it may not match the citation style you are using. For guidance on formatting citations, please see the UNC Libraries citation tutorial . We revise these tips periodically and welcome feedback.

Anson, Chris M., and Robert A. Schwegler. 2010. The Longman Handbook for Writers and Readers , 6th ed. New York: Longman.

Baron, Dennis E. 1989. “The Passive Voice Can Be Your Friend.” In Declining Grammar and Other Essays on the English Vocabulary , 17-22. Urbana, IL: National Council of Teachers.

Hjortshoj, Keith. 2001. The Transition to College Writing . New York: Bedford/St Martin’s.

Lanham, Richard A. 2006. Revising Prose , 5th ed. New York: Pearson Longman.

Orwell, George. 1968. “Politics and the English Language.” In The Collected Essays, Journalism and Letters of George Orwell , edited by Ian Angus and Sonia Orwell, 4: 127-140. New York: Harcourt, Brace, Javanovich.

Rosen, Leonard J., and Laurence Behrens. 2000. The Allyn and Bacon Handbook , 4th ed. Boston: Allyn and Bacon.

Strunk, William, and E.B. White. 2000. The Elements of Style , 4th ed. Boston: Allyn and Bacon.

Trimble, John R. 2000. Writing With Style , 2nd ed. Upper Saddle River, NJ: Prentice Hall.

Williams, Joseph, and Joseph Bizup. 2017. Style: Lessons in Clarity and Grace , 12th ed. Boston: Pearson.

You may reproduce it for non-commercial use if you use the entire handout and attribute the source: The Writing Center, University of North Carolina at Chapel Hill

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Active and passive voice.

This handout is also available for download in PDF format .

We refer to a sentence as being in the "active voice" when the subject is performing the action of the sentence (the verb). A sentence is in the " passive voice" when the subject is being acted upon by the verb. For example, the following sentence is in the active voice: "She ate the hamburger." She is the subject, and she is doing the eating . On the other hand, this sentence is in the passive voice: "The hamburger was being eaten by her." The hamburger is the subject, and it's being eaten , or being acted upon, by the verb. What was the original subject in the active-voice sentence is now relegated to being the object of the sentence.

Many of us have been taught to avoid using the passive voice at all costs, but following this rule doesn't always make an essay better! Instead, you need to remember these two basic principles:

• Using the active voice emphasizes the person or agent who performs an action.
• Using the passive voice emphasizes the recipient of the action, or sometimes the action itself.

Take a look at the examples below to see how active voice is not always superior to passive voice.

• Passive: Atlas.ti software was used for qualitative data analysis.
• Active: The researchers used Atlas.ti software for qualitative data analysis.

The active option, which uses the third person ("the researchers"), is grammatically correct but sounds a bit awkward. Again, the authors of this article are emphasizing aspects of their methodology, one of which is their software choice. Thus, their use of the passive voice is acceptable and appropriate.

• Passive: The methods and principles by which each process in product synthesis could be analyzed were proposed by Choudhary.
• Active: Choudhary proposed the methods and principles by which each process in product synthesis could be analyzed.

In this case, the active voice is the better choice. The literature review section of a paper often seeks to delineate the most important contributions in the field, which makes actors/agents/authors important. In the example above, the active sentence reads much more clearly and concisely.

Five Times to Use Passive Voice

• Example: After long debate, the proposal was endorsed by the planning committee.
• Example: The data processing department presented what proved to be a controversial proposal to expand its staff. After long debate, the proposal was endorsed by…
• Example: Mistakes were made.
• Example: Every year, thousands of people are diagnosed as having cancer.
• Example: Visitors are not allowed after 9:00 p.m.

Credit: Adapted from "Grammar Crash Course Packet," Kalee Hall, The Writing Center

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Active Vs Passive Voice in Research Article Writing

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Active Vs Passive Voice in Research Article

Introduction to active and passive voices in research articles.

Active and passive voices refer to the sentence construction used. In active voice, the subject performs an action and is the grammatical agent of a sentence. In passive voice, the subject is not present in a sentence or does not do anything; instead, it is acted on by another verb or word.

It is important to use active voice in research articles because it makes sentences more concise. Passive voice should only be used when it is necessary to emphasize an actor or hide its identity for some reason.

Active voice is when the subject is doing something to an object. Passive voice is when there is no action in the sentence.

Both active and passive voices are grammatically correct. However, when writing in passive voice, readers are more likely to get lost or have a difficult time understanding what actually happened.

The best way to avoid confusion with passive voice is to make sure that the verb agrees with who or what you want as your subject and that you include any important information that was omitted by using an introductory phrase or clause.

Active vs Passive Voice: The Difference Between the Two

Passive voice is a less direct way of expressing an idea. It is not as engaging and does not give the reader much information about what happened.

Passive voice is a less direct way of expressing an idea. It gives the reader few details or specific information on what happened in the sentence. A passive sentence is more like a generalization than a statement that specifically describes an event in detail.

The difference between the two types of sentences can be seen when writing sentences about events — one type (the passive voice) often leaves out verbs and makes sentences sound less direct and engaging, while the other type (active voice) uses verbs to make statements more direct and engaging for readers.

Passive voice is used when the subject of a sentence receives the action

Passive voice is an important topic for college students writing papers.

Passive voice is used when the subject of a sentence receives the action instead of initiating it. It can be useful in certain situations, but it should not be used too often as it can make your writing seem weak or unclear.

Passive voice is an important topic for college students writing papers, because it can make your work seem weak or unclear in certain situations.

Active voice is more engaging than passive voice and has a stronger effect on readers because it engages them in what’s happening

Active voice is more engaging because it engages the reader in what is happening. They are an active participant in the scene, rather than a passive observer. Passive voice can sound unprofessional and have a weaker effect on readers because they are not engaged.

Passive voice might sound formal and academic but it can have a less powerful effect on readers when compared to active voice. This is because they are not actively involved in the scene as an actor, but instead as an observer who is being told about what’s happening.

4 Reasons Why You Should Write With Active Voice

Active voice will make your writing more powerful and persuasive.

When you write in active voice, it is easier to connect with the reader and make a connection.

The common misconception about active voice is that it makes things sound aggressive or rude.

It doesn’t matter which form of writing you choose, it’s important to be consistent.

Active voice will help a writer to reduce passive voice use, which can confuse readers or the point of your message.

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Literature Reviews

Writing the literature review.

Generally, the purpose of a literature review is to identify, synthesize, and analyze a published body of knowledge on a topic. A review may be an end in itself (a survey of what is known about a topic) or a preface to and rationale for engaging in primary research. A systematic review of literature makes transparent the criteria for including and excluding literature, primarily in the methods section. 

Basic Guidelines

• Be selective. Include only studies that are relevant to your topic. 
• Organize the literature review around major topics of concepts. Use headings or topic sentences to communicate your organizational principle. 
• Synthesize and evaluate – don’t just summarize. 
• Use summary to help the reader relate each section to the larger topic and to make clear the movement of your argument. Where have we just been and where are we now going? 
• Tell a story about the research. Use this to guide your organization. 

Organizing Tips

Place background information (e.g., descriptions of a clinical situation or a theoretical model) at points where it will be most useful for readers. For example, if several researchers have used the same theoretical approach, describe that framework prior to reviewing those studies. 

Divide your review into sections with appropriate descriptors, following the guidelines of the documentation system you are using. Your outline provides the basis for this division because it has already grouped studies together under headings and subheadings. Note that you may want to cite a particular study in more than one section. 

End each section in your review with a summary sentence or paragraph. The length of summary should reflect the length of the section. End the entire review with a comprehensive summary that reiterates the most significant aspects and findings. This final summary (the “Discussion” section listed in your overview) is also the place to make major comparisons, offer your opinion or critique the adequacy of research approaches and methods, and point out critical inconsistencies. Your critique paves the way for you to close your review by posing unanswered questions, recommending approaches and variables for future research, and suggesting implications. If your review is a preface to your study, your critique should reinforce the rationale for conducting your research. You will then state your research question(s) and/or hypotheses. 

Suppose you’re planning to write a literature review regarding the effectiveness of short-term group therapy in reducing depression among nursing home residents. You have now collected research and made a list of the areas covered by your research: 

Elderly people in nursing homes  Pharmacological treatment of depression  Use of psychotherapy among elderly people  Depression – causes, behavioral manifestations, effects  Measurement tools for depression  Societal attitudes toward aging  Psychological problems in elderly people  Depression in elderly people  Effects of group therapy  Side effects of drugs used to treat depression. 

Possible outline for the literature review: 

 Depression in general (problem)  Theories of causation   Behavioral manifestation   Effects   Depression in elderly people, particularly in nursing homes (problem and its scope)   Approaches other than therapy (previous work done)   Effects of therapy on depression  Long-term – disadvantages   Short-term   Group 

Notice that the outline proceeds from general to specific. As you move down the outline, you will deal with material in increasing depth, just as the relevance of the information to your own project increases. 

Sentence-Level Concerns

In the excerpts below, consider how the following affect readability: focus, sentence strength, citation placement, transition, and active vs. passive voice. 

The relationship between motivation and the decision to acquire literacy has been studied by Smith (1975), Jones (1983), and Brown (1988). Motivation involves a number of expectations (Snappe, 1986; Krakel, 1988). A large study conducted by Amundson (1981) explored the beliefs of people entering literacy programs, specifically outcome expectations and self-efficacy despite obstacles. Paape (1979), and in a follow-up project Johnson (1985), studied resistance to motivational efforts or the tendency to ignore information about an issue that is difficult to acknowledge. A literacy promotion program needs to overcome the tendency to minimize the problem and to help people believe.

Research suggests that several factors influence an adult’s decision to acquire literacy. People need to be motivated to make such a decision (Smith, 1975; Jones, 1983; Brown, 1988). Motivation encompasses at least two categories of expectations (Snappe, 1986; Krakel, 1988). One must believe that literacy will affect one’s life positively (outcome expectations) and also that one can succeed in the effort to learn new skills (self-efficacy) despite obstacles (Amundson, 1981). Other research shows that when the problem is difficult to acknowledge, people tend to ignore information about it, i.e. to resist motivational efforts (Paape, 1979; Johnson, 1985). All these findings imply that a literacy promotion program needs to overcome the tendency to minimize the problem and to help people believe. 

Comparing these paragraphs should illustrate how certain rhetorical choices affect readability and clarity. Some guidelines: (1) Use headings and topic sentences to tell readers what the topic is and what point the material is contributing to the discussion. (2) Test sentences for relevance to the central point. (3) Don’t just point to the existence of literature on the topic; write about methods or results in the studies you discuss. (4) Place citations where they don’t interrupt or distract from the line of thought you’re presenting. (5) Use transitions. (6) Use strong, content laden, active verbs.

• Keep your tone objective as you summarize the research but don’t allow your objectivity to turn your review into an annotated bibliography (a laundry list). Rather, point out as you go along how studies relate to one another (e.g., “Smith (1988) and Jones (1990) used different samples to examine the same phenomenon”). 
• Be analytical; writing a review is an exercise in comparative thinking. Save your critique (opinions and judgments) for your final discussion, where they will be more effective and meaningful to the reader. 
• These connections may need to be made within a paragraph as well as among a group of paragraphs  (e.g., “Jones (1989) and Smith (1991) were among the first to examine the effects of childhood  abuse....Like Jones, Smith also used the State-Trait Inventory but included males in his sample” or “Lee’s  studies of learned helplessness support this study’s perspective of behavior modification as situation-specific”). 
• Use speculative language. Hypotheses are not proved; they are supported. Theories are not verified, but they may be tentatively accepted. Don’t make blanket generalizations. Use “may” rather than “will,” and modify your commentary with words such as “a majority of,” “to date,” and “appears to occur” because tomorrow’s findings may nullify today’s.
• Choose verbs that accurately describe what the research did; hypothesized, questioned, developed, implemented, measured, tested, and modified have quite different meanings. Avoid using “should” and “must”; they tend to sound preachy.
• Use direct quotations sparingly. They often take up more space than sentences constructed to summarize the original. Quotations may include concepts and vocabulary unfamiliar to the reader. 
• wordy phrases : “the area of education” = “in education”, “at this period of time” = “at this time”, “in an accurate manner” = “accurately”; and 
• unnecessary modification : “exact replica,” “ultimate outcome,” “personal opinion”. 
• Use verb tenses appropriately. Use the past tense to summarize studies and procedures (e.g., “Danz measured four dimensions of self-efficacy...He modified two questionnaires”). Use the present perfect tense to suggest that something has occurred more than once in the past and may be continuing (e.g., “During the last two decades, researchers have often focused on the effects of posttraumatic stress disorder”). Use the present tense to describe theory and instruments (e.g., “Developmental tasks are central to Piaget’s theory”; “The STA uses a Likert scale to measure stress”), to discuss and critique (e.g., “The use of self-report has two major limitations”) and to generalize (e.g., “These findings suggest that adult learners prefer self-evaluation”). 
• Use the active and the passive voice appropriately. The active voice (“Cole replicated this test with four samples”) is less wordy and more dynamic than the passive voice (“This test was replicated with four samples by Cole”). However, it is effective to use the passive voice when the object is more important than the subject (e.g., “The children in group one were shown the videotape”); when the subject is unknown (“This phenomenon was first described according to eighteenth century standards”); when it would not be a good idea to identify the subject (“The first set of data was not accurately coded”); and when placing the object before the subject more clearly links into a previous sentence or paragraph (“...screen methods that enhance job satisfaction. These screening methods were also evaluated...”). Overuse of the passive voice suggests that research is occurring by itself and confuses the reader about who is doing what.

[Adapted by Lisha Storey from Elizabeth Tornquist's, From Proposal to Publication (1986)]

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Active vs. Passive Constructions | When to Use the Passive Voice

Published on June 29, 2023 by Shona McCombes . Revised on August 23, 2023.

The passive voice occurs when the person or thing that performs an action is not the grammatical subject of the sentence. Instead, the person or thing that receives the action is placed before the verb . Passive sentences are formed using the verb  to be combined with a past participle.

Active voice

The dog bites the bone.

Passive voice

The bone is bitten by the dog.

In a passive construction, the actor does not have to be named at all.

Passive construction

The bone is bitten .

Writers are often advised to avoid the passive voice, but it is not a grammatical error. In academic writing , this type of sentence structure is sometimes useful or necessary. However, overusing it can make your writing unclear or convoluted.

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Table of contents

Avoiding the passive voice, using the passive voice, other interesting articles.

In most cases, it’s best to use active sentence constructions where possible. Sometimes the passive voice makes a sentence less clear by obscuring the actor.

Who made the decision? To properly understand what occurred, we need to know who was behind the action. This is possible in the passive voice, but the sentence becomes convoluted.

An active construction is preferable for clarity and concision .

If you write a passive sentence, consider carefully whether leading with the actor would strengthen your point.

This is also relevant when discussing previous research: active constructions that specify who is responsible for findings can make your writing more credible and convincing.

• Evidence   has been found of nonhuman primates engaging in ritualistic behaviour.
• Smith (2015)  found  evidence of nonhuman primates engaging in ritualistic behaviour.
• Several recent studies have found evidence of nonhuman primates engaging in ritualistic behaviour.

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Some types of academic writing do not permit the use of first-person pronouns . In these cases, the passive voice can be used for referring to your own actions.

If you use the passive voice in more complex sentences, make sure to avoid dangling modifiers .

The passive voice is often also appropriate when the subject of an action is unknown or unimportant to the meaning of the sentence.

In this case, the object of the action – the votes – is more important than who did the counting. Specifying the actor wouldn’t add any useful information to the sentence.

With verbs like require , there is often no particular actor who does the requiring , so the passive voice is used to state a general sense of necessity or obligation.

If you want to know more about AI for academic writing, AI tools, or writing rules make sure to check out some of our other articles with explanations and examples or go directly to our tools!

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What is Passive Voice? Definition, Examples of Passive Sentences in Writing

Home » The Writer’s Dictionary » What is Passive Voice? Definition, Examples of Passive Sentences in Writing

Passive voice definition: The passive voice is a style of writing where what would be the object of a sentence becomes the subject of the sentence.

What is Passive Voice?

What does passive voice mean? The passive writing voice occurs when something that is ordinarily “done by” the subject of a sentence is “done by” the object of a sentence .

In the passive writing voice, whatever is doing the action of the sentence is not the grammatical subject of the sentence.

Passive Voice Examples:

• The work was completed by Jaime.

Even though “Jaime” completed the work, “Jaime” is not the grammatical subject of this sentence. The subject of this sentence is “work.”

• The ball was hit by Johnny.

Again, in this sentence, rather than say, “Johnny hit the ball.” the ball becomes the subject of the sentence.

How is the Passive Voice Formed?

Passive construction: The passive writing voice is formed when what should be the object of a sentence becomes the subject of a sentence.

Examples of Passive Voice:

• Austin bought clothes.
• “Austin” is subject; “clothes” is object
• The clothes
• The clothes were bought.
• The clothes were bought by Austin.

Passive vs. Active Voice: What’s the Difference?

What is a passive sentence? The passive writing voice occurs when the action is done by what seems like it should be the subject.

Active Voice Example:

• Shakespeare wrote the play.

In this sentence, Shakespeare is “doing” the action of the sentence.

Active vs. Passive Voice Examples:

• Shakespeare wrote the play. (active)
• The play was written by Shakespeare. (passive)

The subject is typically clearer in active voice whereas in passive voice it may seem like the object is the subject.

More Examples:

• President Barack Obama signed a rescue package on Thursday for financially strapped Puerto Rico, which is facing more than $70 billion in debt and a major payment due Friday. – ABC News (active)
• A bill designed to reclaim businesses that have left the state and better Missouri’s port infrastructure was signed into law by Gov. Jay Nixon Tuesday. – The Missouri Times (passive)

Should You Avoid Passive Voice in Writing?

The passive voice is used less frequently in writing. However, it should not be avoided altogether.

Some phrases in English are always stated in the passive voice (i.e. The book was written by Herman Melville).

Stylistically, passive voice can be used as well. The passive voice can add style when:

• the writer wants the “punch” to be at the end of a sentence;
• the agent is unknown or unimportant (i.e. The person doing the action is unknown.);
• the writer wants to hide the agent’s identity

Many will say that the passive voice is not permitted in good writing. This is untrue. Good writers know how to delicately blend the passive writing voice with active sentences. Like all writing techniques, passive voice should be used with intention and purpose.

Passive Voice vs. Active Voice Exercises

• This episode was brought to you by Coca-Cola.
• Children danced in the halls to celebrate the last day of school.
• The china was made in Japan.
• We bought a new entertainment unit.
• The fossil has been discovered.

See Answers Below.

Summary: What is a Passive Voice?

Define passive voice: The definition of passive voice is when the recipient of the verb’s action becomes the subject of a sentence .

The passive voice is not common in writing. However, it is a stylistic choice that writers will occasionally use for effect.

The passive writing voice occurs when what would be the object of a sentence becomes the subject.

For more information on English voice, see our full article on the active voice.