Literature Reviews
- Getting Started
- Choosing a Type of Review
- Developing a Research Question
- Searching the Literature
- Searching Tips
- AI in Lit Reviews [beta]
- Organizing the Literature
- Writing the Review
- Further Resources
Grey Literature

Grey Literature is research information that is public (not behind paywalls).
It can include government reports, web content, documents from professional organizations, and conference abstracts. It might be relevant for your literature review.
Avoiding Bias
SELECTION BIAS
This occurs when you don't do a thorough search of the existing literature. Your review doesn't need to find every document ever published, but should not be misleading. It will be misleading if you leave out whole categories of studies or only look at a haphazard section of studies.
Ways to avoid selection bias:
- search multiple scholarly databases (each contain different documents)
- search for grey literature
- search on multiple days (new research is being published daily)
- search using a variety of different search terms
Searching using AI
AI-assisted literature searching applies artificial intelligence and machine learning to the act of searching the literature, possibly finding connections that you wouldn't normally find. The tools below are a starting point.

Raxter
— https://raxter.io
Research Rabbit
— researchrabbit.
Iris
— https://iris.ai
Scite (paid app | instructions)
— https://scite.ai
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.
STRATEGIES TO START YOUR RESEARCH
- 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).
- You can learn how to find ebooks through U-M Library on this guide.
- 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.
Selecting Databases to Search
The best place to search for sources is in scholarly databases. The Library provides online access to these for free to current U-M students, faculty and staff. On the Library's homepage, there's a list of commonly used databases underneath the search box (shown below). The Library has access to hundreds of databases. Not sure which ones to use? Contact a Subject Specialist.

GET HELP FINDING SCHOLARLY DATABASES
Library Subject Specialists are available to help throughout the literature review process, including recommending which scholarly databases to search based on your topic. On the Library's homepage, click Research and Scholarship (on the top toolbar), then click Help with Research and finally click Find a Specialist.

BE CAREFUL USING GOOGLE SCHOLAR
Why? Google doesn't divulge how they determine if a document is scholarly or not (whereas scholarly databases do). Sometimes GoogleScholar includes documents that aren't scholarly, like this school lunch menu.

Before using a document that you find in Google Scholar, you'll need to determine if it is from a credible source by researching the author, publication venue, etc.
Developing & Executing Your Search Strategy
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" |
Look over the searching techniques on the Searching Tips tab to learn how to combine your search terms.
EXECUTING YOUR SEARCH STRATEGY IN A SCHOLARLY DATABASE
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).

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

How Much Literature is Enough?
Remember: a comprehensive literature review (like for a dissertation) will require more sources than a selective literature review (like for a course assignment).
THINGS TO CONSIDER
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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.
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New literature is being published daily. You must stop searching at some point.
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Consider the volume of research on your topic. A larger volume equates to more searching. For example:
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Type II diabetes = large amount of literature
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Multiple Myeloma [rare cancer] = smaller amount of literature
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Evaluate the resources available to you
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Time: How much time do you have to complete this review?
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Collaborators: Do you have collaborators or colleagues helping to complete the review?
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Reflect on your Research Question
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Continually revisit your Research Question and objectives — ensure the literature you've collected directly address your research goals.
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