Database Search Tips: Keywords vs. subjects

To find subject headings for your topic:

• Look to see if the database has an online thesaurus to browse for subjects that match your topic (check the Help screens).
• Some databases publish thesauri in print (e.g. Thesaurus of Psychological Index Terms for the PsycInfo database).

Another way to find subject headings:

• Start with a keyword search, using words/phrases that describe your topic.
• Browse the results; choose 2 or 3 that are relevant.
• Look at the Subject or Descriptor field and note the terms used (write them down).
• Redo your search using those terms.
• Your results will be more precise than your initial keyword search.

Subject headings describe the content of each item in a database. Use these headings to find relevant items on the same topic.  Searching by subject headings (sometimes called descriptors) is the most precise way to search article databases.

It is not easy to guess which subject headings are used in a given database. For example, the phone book's Yellow Pages use subject headings. If you look for "Movie Theatres" you will find nothing, as they are listed under the subject heading "Theatres - Movies."

Keyword searching is how you typically search web search engines.  Think of important words or phrases and type them in to get results.

Here are some key points about each type of search:

Keyword searches:

• use natural language words describing your topic and are good to start with.
• are more flexible to search by since you can combine words together in many ways.
• look for keywords anywhere in the record - not necessarily connected together.
• may yield too many, too few, or irrelevant results.

Subject searches:

• are pre-defined "controlled vocabulary" words used to describe the content of each item (book, journal article) in a database.
• are less flexible to search by since you need to know the exact controlled vocabulary wording.
• look for subject terms only in the subject heading or descriptor field.
• may give too many results - also uses subheadings to focus on one aspect of the broader subject.
• give results that are usually very relevant to the topic.