If your search returns very few records, or you are missing studies you expected to find, you can try:
Look for more synonyms
Did your search strategy leave out any words that are similar to the terms in your research questions? Take another look at a thesaurus or look at studies you expected to find to see if there are MeSH terms you are missing.
Get rid of quotation marks
If your terms are surrounded by quotation marks, you’re limiting your search to articles that contain those exact phrases. That means you’re leaving out literature that includes other variations of those same terms. For instance, a search with “kidney disease” will miss studies about disease of the kidney and kidney diseases.
To capture multiple spellings of a term such as run, runs, running, you can use truncation. That’s where you write the root of the word followed by an asterisk or other database-defined character.
Example: hemorrhag will capture hemorrhage, hemorrhaging, and hemorrhagic.*
Look for misspellings or different spellings
Did you know “anemia” is also spelled “anoemia”? When you’re searching international literature, you might run into cases where academics from different countries use different spellings for the same term. Use both versions to expand your search.
If you feel like you’ve included all possible synonyms and MeSH terms in your search, try removing any filters you may have added.
Once you’ve hit the sweet spot between finding too many studies and not enough, you’re ready to start looking at each individual article to determine if it truly addresses your research questions. We call this step “screening your studies.”