When a user performs a basic search in a database, they are using keywords. While keywords are a great way to start a search, a user could also search with terms from a controlled vocabulary.
Controlled vocabularies are standardized, organized sets of terms that databases use to describe content in a consistent fashion. Many databases have their own, unique controlled vocabulary (see table below).
|Database||Controlled Vocabulary Name||Tutorial|
|CINAHL||CINAHL Subject Headings||Using CINAHL/MeSH Subject Headings|
|EMBASE||Emtree||Searching in Embase|
|PsycInfo||Thesaurus||APA Thesaurus of Psychological Index Terms|
|Pubmed||MeSH||MeSH in MEDLINE/Pubmed: A Tutorial|
Compared to keywords, controlled vocabulary terms usually generate fewer and more relevant results. However, a user must use the exact term. The tutorials in the above table cover how to find and use these terms.
- If the initial keyword search gave too many or too few results, try controlled vocabulary terms.
- If a researcher is doing a comprehensive search (e.g. a systematic review), combine both keywords and controlled vocabulary terms to increase the number of resources retrieved.
- If a user is looking for background information, a keyword search generally suffices.