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Literature Review Guide

Overview of the iterative steps involved in using library databases to search & review the scholarly literature

red banner - how do I f ind relevant articles.

What are Search Operators?

Unlike Google, which uses deep neural networks and machine learning to search, many of the databases we use for research do not operate with AI learning. In Google searches, we often use plain language to structure our searches, as it is able to interpret our meaning. The databases that we use for research are not capable of that analysis, so we need to tell the database how to interpret our keywords together, not as sentences, but as logic statements that computers can read.

For example:

  • Google search: what is the weather today
    • Search results will return results about the weather on today's date, in my location, even though I have not given it the date or location.
  • Database search: what is the weather today
    • Search results will return articles that contain any or all of the following words: what, is, the, weather, today

Boolean Operators

There are 3 Boolean operators used in virtually every database search: AND, OR, and NOT. We write them in all capital letters to let the database know that they are operators, not search terms.

Boolean Operator: AND

children AND adolescents

  • Will return results that contain BOTH the term children and adolescents
  • Use this to tie your main terms together

Boolean Operator: OR

therapy OR treatment

  • Will return results that contain EITHER the term therapy, treatment, or both terms.
  • Use to tie your synonyms, related terms, and alternate spellings together

Boolean Operator: NOT

Pets NOT cats

  • Will return results that contain the word pets, and DO NOT contain the word cats
  • Use this to filter out irrelevant results

explaining boolean operators using venn diagrams

Cecelia Vetter, CC BY-SA 4.0, via Wikimedia Commons

Narrow or Broaden Your Search

Too Many Results?

Before you review any results, be sure to get them to a manageable number to go through all relevant results. Try one or more of the ideas below:

  • The main way to narrow is to add more facets. If you only search for "Eating disorders", that will be too broad. Add treatments, populations, etc. to your search.
  • If you aren't sure how you want to narrow your topic, you can add filters to your search. The filters available depend on which EBSCOhost database you are using. You can add filters to your search by clicking on "Filters" under the search box once you have run your search.
    • This will bring up a sidebar menu with filter options. Filter options often include Peer Review, Publication Type (journal, magazine, book, dissertations, etc.), Language, or Methodology (literature review, qualitative, quantitative, etc.). Some subject specific databases include relavent filters like population filters in APA PsycInfo, and industry filters in Business Source Premium.
    • Choose the filters you want to use and select "Apply". The more filters you add, the less results you will get.

ebscohost search highlighting filter button

Too Few Results?

If there are not enough relevant results, try one or more of the following:

  • Find additional subject headings
    • For any resource that looks useful, click "More" to see more of the subject headings used in that article.

article in ebscohost highlighting where to view more subject headings

  • Remove a concept from the search
    • If your topic has many facets, you might need to find articles on just two facets at a time, rather than trying to find articles that match the intersection of all parts of your topic.