The goal of systematic review searches is to identify all relevant studies on a topic. Therefore, systematic review searches are typically quite extensive. It is necessary, however, to strike a balance between striving for comprehensiveness and maintaining relevance when developing a search strategy. Increasing the comprehensiveness (or sensitivity) of a search will reduce its precision and will retrieve more non-relevant articles.
The goal of a systematic review search is to maximize recall and precision while keeping results manageable. Recall (sensitivity) is defined as the number of relevant reports identified divided by the total number of relevant reports in existence. Precision (specificity) is defined as the number of relevant reports identified divided by the total number of reports identified.
Issues to consider when creating a systematic review search:
Librarians can recommend databases and other sources to search for a systematic review. The sources you choose will depend on your research question and the disciplines in which relevant research may be conducted. Below is some guidance for choosing scholarly databases in a number of research areas. Check the library's database list for a full list of available sources across all disciplines.
Librarians can also help with designing complex searches using the specialized syntax of individual databases. Consult with a librarian if you have questions.
Note that these databases largely focus on the published, peer-reviewed literature. For guidance and resources for searching other types of information (i.e., gray literature), see the next tab in this guide.
There are three Boolean operators that are used to connect terms and tell databases how and what to search for: AND, OR, NOT.
AND is to combine terms, usually unlike terms/concepts. AND narrows a search. Example: social media AND teenagers
OR is typically used with synonyms and similar terms. OR broadens a search. Example: teenagers OR adolescents
NOT is used to exclude something. Example: teenagers NOT bullying
We use parentheses to help group parts of the search query, especially when we have several parts, and to tell the database the order of the query. Think about the search query as a mathematical equation.
All put together, they look like this:
social media AND (teenager OR adolescent) NOT bullying
Truncation allows you to find different endings to a word. The symbol in many databases is: *
Example: teenage* captures teenager, teenagers, teenaged.
Be careful not to truncate too far into the word. For example: car* will capture car, cardiology, carbohydrate, caramel, carabidae, carassius, and thousands more words.
carbohydrat* would be a better way to truncate.
Wildcards are symbols used within a word to represent a letter for a variation on spelling. While not every database uses them anymore, for those that do, the symbol is often ? or $, though always best to check the database documentation.
Example: behavio$r captures both the American spelling, behavior, and the British spelling, behaviour