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Literature Reviews: Searching the Literature

Starting to Research Your Topic

Before you can searching for the existing literature, you need to make sure you know what is meant by "the literature," which is usually defined as a collection of all the scholarly writings on a topic. The literature can include peer reviewed articles, books/ebooks, conference proceedings, theses/dissertations, documents published by governmental agencies and non-profit organizations, and other forms of gray literature. 


  • Skim recent textbooks or books. While it's possible that you won't cite them as a source, they will help you understand the breadth of your topic and what aspects researchers have already focused on. But remember that they don't contain the most recently published information (unlike journal articles, for example).
  • Talk with knowledgeable collaborators, colleagues, professors, friends, etc. They may have suggest important authors, journals or documents on your topic. 
  • Look over popular interest sources (with caution!), like Wikipedia.
  • Look at the most highly cited documents on your topic. Many scholarly databases have the ability to sort results by "Cited Highest." See the Searching Tips tab for instructions on how implement this. 
It is helpful to read existing literature reviews on topics similar to yours to get an idea of major themes and how authors structure their arguments. See the Developing a Research Question tab for info on how to search for existing literature reviews.

Selecting Databases to Search


Using Library Search to Find Reference Materials

  • Perform a search from the library's home page and then click the the "Reference Resources" option under the Limit To heading
  • Or, using the same search tool, combine your search terms with the following: encyclopedias OR dictionaries OR handbooks OR companion


  • Use the "Review article" filter under Document Type to find articles that summarize the current state of understanding on a topic



Developing & Executing Your Search Strategy


A search strategy translates your research question into search terms. See an example below.

Research question Concepts Search terms


What are the ethical considerations when using artificial intelligence to document climate change?

1. ethics

2. artificial intelligence

3. climate change

1. ethic*

2. "artificial intelligence" OR AI OR "machine learning"

3. "climate change"

Don't forget to brainstorm as many synonyms for your search terms as possible. Why? Different researchers will use different terms to describe the same topic.


Look over the searching techniques on the Searching Tips tab to learn how to combine your search terms.


The screenshots below shows how you can enter your search terms into two different databases, Scopus (top) and ProQuest (bottom). Searches can be built using multiple search boxes (as shown below). 

An example of a Scopus database search screen with three distinct search boxes. Box one includes "artificial intelligence" OR AI OR "machine learning". Box two includes "climate change". Box three includes ethic*

You can also build your search using a single search box (as shown below). 

A screenshot of a Proquest database search screen. The search bar includes the following prompt:("artificial intelligence" OR AI OR "machine learning") AND "climate change" AND ethic*

How Much Literature is Enough?

Only you can answer this question. Why? Because you're the person who determined the scope of your literature review. For a reminder on how to determine scope, see the Choosing a Type of Review tab. 


Remember: a comprehensive literature review (like for a dissertation) will require more sources than a selective literature review (like for a course assignment). 


  1. Searching for, reading and understanding the existing literature is more of an art than a science. The more you do, the more you'll understand the current state of research and therefore know if you've found enough literature. 

  2. New literature is being published daily. You must stop searching at some point. 

  3. Consider the volume of research on your topic. A larger volume equates to more searching. For example: 

    • Type II diabetes = large amount of literature

    • Multiple Myeloma [rare cancer] = smaller amount of literature

  4. Evaluate the resources available to you

    • Time: How much time do you have to complete this review?

    • Collaborators: Do you have collaborators or colleagues helping to complete the review? 

  5. Reflect on your Research Question

    • Continually revisit your Research Question and objectives — ensure the literature you've collected directly address your research goals.


Thanks to Librarian Jamie Niehof at the University of Michigan for providing permission to reuse and remix this Literature Reviews guide.

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