This page includes information on search techniques for searching databases. View the Search Development page of this guide for guidance on how to use these techniques to develop a SR search strategy.
Search Techniques
Searches are typically organized using the Boolean operators OR or AND. OR is used to combine synonyms and related terms for the same concept AND is used to combine different concepts.
Example: Living Donor AND Deceased Donor
Example: Living Donor OR Deceased Donor
The blue in both images represents the article retrieved. Using AND to combine the two search terms will only retrieve results where both terms are used. Using OR to combine the two search terms will retrieve results that use either term separately or both together.
More Search Techniques
- Database limits are database-provided limit features that allow users to narrow results based on criteria, such as language, publication type, publication date, etc.
- Database limits are generally NOT recommended for use in systematic reviews, due to their fallibility, unless there is justification provided.
- For example, for example if you want to limit your search results by date, you need a good reason to do so and must explain your reasoning in your protocol and manuscript.
For a more detailed explanation, see ITEM 3: LIMITS AND RESTRICTIONS of the PRISMA-S Explanation and Elaboration document.
- PRISMA-S (Searching)Extension to the PRISMA Statement for Reporting Literature Searches in Systematic Reviews.
Hedges or filters are published search strategies developed by experts and are typically validated. Hedges are often used to narrow results by specific study designs, publication types, population, or topic.
For a more detailed explanation, see ITEM 4: SEARCH FILTERS of the PRISMA-S Explanation and Elaboration document.
- PRISMA-S (Searching)Extension to the PRISMA Statement for Reporting Literature Searches in Systematic Reviews.
Truncation or wildcards are techniques that broadens your search to include various word endings or word variations or spellings. Typical search symbols include the asterisk (*), used to replace one or more characters, usually at the end of the word, and the question mark (?), used to replace a single character, either inside or at the end of the word.
For example:
- toxic* retrieves toxic, toxicity, toxicology, etc.
- behavio?r retrieves behaviour and behavior
- p?diatric retrieves pediatric and paediatric
Tips
- Each database has unique rules. View the help section of each database for instructions on how to search with truncation and wildcards.
- In some instances, it may be better to use the various versions of the word instead of truncation. It depends on the word, word variations, and specific database.
- Test your search in each database with and without truncation before making a decision on which strategy is best for your search.
A phrase search will search for two or more words as an exact phrase. To do so, enclose the words in quotation marks.
For example: "cultural humility."
If you are considering using phrase searching for an SR search, compare your strategy with and without phrase searching in order to determine if you would miss relevant literature using phrase searching.