What is controlled vocabulary?
Most research databases will have what are essentially tags attached to each article/record, and just like tags you can search a controlled vocabulary term to find similar articles. They go by different names/jargon depending on the database but you might also know them by the name “subject headings.” The difference is that what the controlled vocabulary for a particular term is will be determined by whatever entity or company runs the database, hence the “controlled” part. You have to use pre-existing terms rather than invent your own. Usually a big part of a search will be discovering what terms are related to your topic. Sometimes they’re exact, sometimes you only get a broad term for a more narrow topic, sometimes they don’t exist (yet).
In medical librarianship, usually the most well known controlled vocab are MeSH (Medical Subject Headings), which are used in the government citation and abstract repository PubMed. If you ran a search for “asthma” [MeSH] in PubMed, you’d retrieve all the articles with that tag, essentially. The rub is, not everything is tagged with a MeSH term in PubMed, so it’s best practice to also search the text of article records as well. Something like (“asthma” [MeSH] OR “asthma” [Title/Abstract])
