How PubMed is Democratizing “Expert” Literature Searching

In May 2020, the U.S. National Library of Medicine (NLM) officially launched their updated version of PubMed, making it the default that will replace the legacy version going forward. First released in January 1996, as the Internet was just becoming available to the masses, PubMed has seen multiple redesigns over its almost 25 years of existence. New features have been added and improved upon continuously, with some of these changes more obvious to regular PubMed users than others. 

Millions of people around the World search this freely-available biomedical bibliographic database daily, with both experienced and non-experienced searchers in the mix. One noteworthy change to the updated version (which will likely go unnoticed by most searchers unless they choose to do an Advanced search and look at the Details by clicking on the carrot symbol >), is that PubMed’s search translation functionality (or automatic term mapping) has also been further enhanced.

In fact, the folks at NLM may now have come closer than ever before to elevating the PubMed search queries entered by less experienced searchers to truly “expert searcher” level search statements.

Here’s an explanation – an “expert searcher” typically approaches a comprehensive literature search by making these considerations regarding the concept(s) of interest: they will compile synonyms/subject headings, alternate/foreign spellings, singular and plural forms, and multiple term endings (suffixes), as well as, develop appropriate logic statements (using Boolean operators) to correctly combine these search terms.

Simply by inputting a term or two in the PubMed search box and clicking on the “Search” button, a non-expert can go from, say:

Search: lymphedema prevention 

…a two keyword query that then gets translated behind the scenes by the PubMed search engine into a rather sophisticated search strategy.

Legacy PubMed was already helping improve searches by mapping to relevant Medical Subject Headings (MeSH) and to foreign spellings, for example, it would have run this search translated to:

(“lymphoedema”[All Fields] OR “lymphedema”[MeSH Terms] OR “lymphedema”[All Fields]) AND (“prevention and control”[Subheading] OR (“prevention”[All Fields] AND “control”[All Fields]) OR “prevention and control”[All Fields] OR “prevention”[All Fields])

 …however, the updated version of PubMed has expanded the translation functionality to also search for singular/plural forms, as well as, incorporate a bit of truncation (ie. prevent*), allowing for relevant alternate term endings, as in the case here with “prevention”, see:

 ((((“lymphedema”[MeSH Terms] OR “lymphedema”[All Fields]) OR “lymphedemas”[All Fields]) OR “lymphoedema”[All Fields]) OR “lymphoedemas”[All Fields]) AND (((((((((((((((((“prevent”[All Fields] OR “preventability”[All Fields]) OR “preventable”[All Fields]) OR “preventative”[All Fields]) OR “preventatively”[All Fields]) OR “preventatives”[All Fields]) OR “prevented”[All Fields]) OR “preventing”[All Fields]) OR “prevention and control”[MeSH Subheading]) OR (“prevention”[All Fields] AND “control”[All Fields])) OR “prevention and control”[All Fields]) OR “prevention”[All Fields]) OR “prevention s”[All Fields]) OR “preventions”[All Fields]) OR “preventive”[All Fields]) OR “preventively”[All Fields]) OR “preventives”[All Fields]) OR “prevents”[All Fields])

Note: If for some reason a searcher wishes to turn off this query term(s) translation functionality, using quotation marks around each term will keep the automatic term mapping from occurring. For example:

Search: “lymphedema” “prevention” 

…now drops the mapping/translating, and only turns into:

“lymphedema”[All Fields] AND “prevention”[All Fields]

…versus inputting it as a phrase surrounded by quotations:

Search: “lymphedema prevention” 

…which will now stop considering the space between the two terms as an implied Boolean operator AND, and so will keep its integrity and be run only as:

“lymphedema prevention”[All Fields]

See this NLM handout for more Tips for Using PubMed or take one of the MSK Library’s New PubMed classes to learn more.