What is Automatic Term Mapping in PubMed? Should I be using it?
Answer
Automatic Term Mapping is a process by which PubMed tries to translate your search terms and match them to terms in specific fields.
When search terms are entered without using quotation marks (Rhinosinusitis VS. "Rhinosinusitis") PubMed will trigger automatic term mapping. The database will first try to find a matching MeSH term. It will also try to map your term to a journal title, author name, or known phrases. If PubMed cannot find a journal title, author or known phrase, it will search for your search term in All Fields. Boolean Operators are also automatically applied. For example, if a term matches to multiple fields, PubMed will use OR to include both terms. If there is no match, PubMed will automatically use AND between your search terms.
While automatic term mapping could be useful if you are still exploring your topic and are unfamiliar with some of the key words used to describe it, the chances of retrieving irrelevant results are high.
Example:
If you enter Common Cold in the search box on the Advanced Search page, you can on the arrow underneath Details to see how PubMed is interpreting your search.
PubMed has correctly identified the MeSH term, but has also automatically placed an AND between common and cold and is looking for these words in All Fields, as well as looking for the phrase common cold in All Fields.
If you want to look for the phrase Common Cold on its own (without PubMed automatically looking for common and cold on their own), enter the search term between quotation marks.
In general, we don't recommend using automatic term mapping, especially when conducting any kind of knowledge synthesis, as it gives you less control over your search and may introduce too much noise.