The process of thoroughly reviewing the scientific literature on a subject can tell you what is already known about it. Then you can determine whether you have enough information to make well-informed, evidence-based choices or whether additional research is needed.
This section presents a step-by-step guide to systematically reviewing the literature on your topic. If you prefer to follow an example, this paper by Thomas-Walters, McNulty, and Veríssimo (2019) has a well-described Methods section.
You probably already have some pre-set ideas about your topic of interest but it helps to have it clearly defined—otherwise a literature review can quickly become overwhelming. So first, try to define your topic in a sentence or two. Then frame it into questions to be answered by the literature review.
Approx. 3.3 million dogs enter animal shelters in U.S. every year but only 1.6 million are adopted. Research suggests that at least 10% of adopted pets are not staying in their first adoptive home. You are interested in making dog adoptions as successful as possible.
Your primary question may be:
- What strategies can advocates use to increase the number of successful dog adoptions?
You can brainstorm additional questions that will help you better understand the problem, depending on how much knowledge on the topic you already have. For example:
- What should be consider a successful adoption?
- Do dogs’ individual characteristics predict adoption success?
- Does dog training influence adoption success?
- Are dog behavioral evaluations effective?
To fully answer these questions, you need to know:
- What does the research say? (Are there any studies on the topic? How many? What are the conclusions?)
- What methods have been used for the research? (Example: How was the success of adoption measured? Was their return rate measured, or rehoming tracked?)
- Is anything missing from the research?
If you intend to limit your research to an online search of animal-cause topics only, we recommend you start with these sources:
We have the world’s biggest library of research about animal issues and animal advocacy right here at Faunalytics. You can explore the library by topic or type of resource.
Google Scholar is a free search engine focused on scholarly databases. It indexes academic journals, books, abstracts, theses, dissertations, and other kinds of scholarly literature.
When using Google Scholar, try sorting the results in different ways and looking beyond the first page of results. The default sort option is by “relevance,” which is partially determined by popularity and may overlook less-cited but still relevant studies (e.g., recent ones).
When conducting a literature search, you need to be both systematic and thorough to avoid overlooking anything and drawing biased or incomplete conclusions. Having a well-prepared search strategy will help.
Write down all the key terms related to the topics. Think about synonyms and related terms, and different ways you might paraphrase the same research question. Group similar terms together. Mind mapping techniques (see step 6) may also help you to brainstorm and keep track of the keywords you can use in your query.
Once you have a complete list of keywords, figure out how you are going to combine them. For keywords meant to get at the same strategy, you might want to use “OR” in your search. For example, if you are looking for information about the effect of plant-based diets on the environment, you need articles that contain words related to plant-based diets AND related to the environment. But some might refer to “vegan” rather than “plant-based” or talk about “sustainability” rather than “environment.” So your keyword combination might look something like this:
(“plant-based” OR vegan) AND (environment OR sustainability OR “greenhouse gas”)
Writing it out that way is the same thing as conducting 6 separate searches: (1) “plant-based” environment, (2) “plant-based” sustainability, (3) “plant-based” “greenhouse gas”, (4) vegan environment, (5) vegan sustainability, and (6) vegan “greenhouse gas.”
You can expand your groups of similar keywords as much as you want (…OR vegetarian OR flexitarian). You can also add another AND followed by another keyword or set of keywords. For more details, see Step 4.
Now it’s time to start your search. If you search more than one database, many of the results you get may appear more than once, but that’s okay. The goal is to be thorough and make sure you don’t miss a result that only appears with one particular search combination.
How To Restrict Your Search And Get More Precise Results
As you saw in the previous section, you can use quotation marks to search for an exact phrase or precise match for a word. With “greenhouse gas” instead of greenhouse gas, you will only get results that have those two words together.
You can also use the minus to remove a specific term from your search. Search results will exclude pages that contain the keyword. For instance, if you use animal welfare -act instead of animal welfare, you will get narrower results because texts that mention Animal Welfare Act will be omitted.
Pay attention to the date of publications. Filter by date to start from the most recent research. Most studies usually include a section that sums up what has been already investigated in the past about the research problem. Older studies can be either disproven or supported by newer research – make sure you pay attention and don’t try conclusions based on the findings of a discredited study.
More about Google operators: https://moz.com/learn/seo/search-operators
How To Widen Your Search And Get More Results
As shown above, in many search engines, you can use the word OR to include several synonyms in one search. For example, by searching for pets OR “companion animals” you can broaden your results.
You can also use * to replace any word in the query, or part of a word. For example:
“animal * shelter” searches for phrases like animal shelter as well as animal rescue shelter, animal control shelter; veg* searches for words like vegan, vegetarian, veganism, and vegetarianism
If your research question is about activism, advocacy, persuasion, donation, or any other general topic that applies to non-animal domains, you can also look for studies in related fields like health, psychology, environmental advocacy, social justice, philanthropy. You can do that by searching them specifically or just by leaving the word animal out of your search and including applicable results from other areas.
From your search results, pick the most relevant articles related to your research problem. Most studies begin with an abstract – a summary of the content – that should give you enough information to decide if the article is relevant. It can also help to read the conclusions first to see if the study brings anything new and valuable into your topic of interest. Then you can scan the whole article for important points and interesting figures.
Take notes on each article to make sure you don’t need to go through it again and again. You can also separate the articles by subtopic if applicable.
Particularly in an online search, it’s very important to pay attention to the credibility of the sources. It’s always good to check:
- Who are the authors? Are they affiliated with academic institutions, or a reputable research organization?
- Is the source peer-reviewed? If you’re reading a summary in the Faunalytics library, it will tell you. Peer-reviewed articles have been subjected to expert scrutiny, so they are more trustworthy.
- When was the article published? Older studies may still be useful, but check whether there’s anything newer to support or dispute the conclusions.
- Was the described study replicated with similar conclusions? If the same thing has been shown more than once, you can have more confidence in the results.
- How big was the sample? A larger sample is more likely to produce valid findings than a small one.
Once you’ve identified a set of articles that relate to your topic of interest, you can move on to your summary. Whatever form you want to use, it’s good to sum up:
- What are the unique concepts in the articles that are crucial to the topic?
- Are the concepts and conclusions conflicting, or mutually supportive? If they conflict, are there differences in the sample or methods that can explain it?
- Is the problem fully covered, or is there a gap that needs further research?
- Have your questions been answered?
To stay organized and systematic, you may want to use some tools and applications dedicated to research management. These are all tools used by members of the Faunalytics research team.
Mind mapping tools: Visualization of your search query into diagrams can make it easier to organize your ideas and keywords and track the possible combinations of words. You can do it either using pen and paper or specialist software like, for example, iMindQ.
Zotero: A free citation manager that makes creating your reference list easier. The citation program will do the work of gathering all the relevant citation information for you. You can even incorporate a Zotero plugin into Microsoft Word and Google Docs to add your citations as you’re writing, which Zotero will format according to the style you need. All these references automatically get added to your bibliography.
Mendeley: A free program that helps to manage and share research papers, references, citations and data. It can be used as a desktop, web, or mobile application with a library of studies that you can add with one click using a browser add-on. A Word plugin also lets you add references to documents with a single click.
OneTab: Whenever the research process generates too many tabs, you can use the OneTab browser addon to convert them into a list of links that you can group, sort and open individually. It also helps to share the list of the links with others.
Evernote: This mobile app with a free basic plan is designed for note-taking, organizing, and archiving.
When presenting information you found during your literature search, it’s important to give proper credit to the authors. Be sure that, at a minimum, you include: the author(s) or organization(s) responsible for the work you’re referencing, the year of publication, and ideally, a link to the source.
If you’d like help citing your sources or using Zotero to manage your citations, feel free to stop by one of our Researchers’ office hours.
If you can’t find what you’re looking for, why not visit our Content Director’s online office hours? The Content Director can help you find specific facts and figures or give you some pointers to improve your search technique.