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Database Search Tips: Subject Searching

a guide to ways to improve your searching in library databases


Have you ever noticed when you search for information that your search results list contains a lot of stuff that isn't really relevant? Frequently, this can be rectified by searching by subjects (or descriptors) as opposed to keywords.

For assistance on searching by subject heading, please contact your subject specialist librarian.

Subject Searching

Subject headings (also called descriptors) describe the content of items in a database. Whether it is a book in the library catalog or an article in a libraary database, there will be at least one and as many as a dozen subject headings assigned. If we can identify a subject heading for our topic and tell the database we want all items with that subject heading, we should see much more relevant results than simply searching by a keyword.

Searching by subject is similar to field searching because subject headings are simply a specific field in the record.

Subject searching is not as intuitive as keyword searching because not all keywords are subject headings or descriptors. That is, you might not be able to guess at a subject heading.

Example: the Vietnam War. If you were looking for books in the library catalog and entered Vietman War as a subject heading, you would find no matches. (There would, however, be a cross-reference to the actual subject heading: Vietnamese Conclict, 1961-1974.)

Many databases include a Thesaurus, an online list of descriptors or subject heading for that database. In the Thesaurus, you can search and find a subject heading which you could use to search by subject.

Here is an example of a Thesaurus entry on Counseling from PsycINFO, a psychology database:

psycinfo thesarus image

The Scope Note is a definition of the term, how it is interpreted in the discipline. You also see Narrower Terms and Related Terms. You will also see Broader Terms. Broader Terms would list subjects that are "bigger" than the subject you are looking at. Narrower terms are "smaller" subjects, sort of like subdivisions within the subject. Related terms are subjects that are not directly a part of the subject, they are a bit tangential, but still may bear exploring.

Finally, if we compare the results of a search by keyword and a search by subject in the database PsycINFO, we see the following:

Counseling as a keyword: 140,213

Counseling as a subject or descriptor: 16,358

So clearly, we can eliminate a lot of unrelevant items on our results list of we search for subjects instead of keywords.