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Search Strategy: Keyword vs. Subject

What are keyword and subject searching?

Online search engines like Google only search with keywords, but when searching library catalogs and databases, you can search with either keywords or subjects.

Natural language Pre-defined “controlled” vocabulary
Familiar Not always intuitive
Searches everywhere in a record or page Searches specific subject terms only
Flexible Less flexible
Often yields irrelevant results Subheadings can help to focus results
May not find all relevant results Results are usually very relevant to topic


Keyword Search When:

  • Your term is jargon, very new, technical, or distinctive/unique.
  • You don’t know the exact title or author.
  • More than one discipline or topic is involved (e.g. autism AND girls)
  • You don't know the subject heading. (Keyword searches are a good way to find a subject heading – start with a keyword search on a term, then look at the subject headings of a relevant result and use the subject terms you find in a new search.)

Keyword searching is how we search most online sources like Google. While this usually results in a large set of results, a keyword search will also return anything that has your term or the string of characters anywhere in the record or page, frequently resulting in many irrelevant results.

Subject Search When:

  • You are looking for information about something, someone, or someplace (i.e. books about Mark Twain, not those written by him).
  • You want to locate all relevant resources about your topic.
  • You are looking for information that may be represented by a term that has many meanings or could occur in various contexts (e.g. “management”). Browse the "subject search results" list to find the Subheading that applies to your topic.
  • You want to exclude results which are not about your topic (e.g. Depression, Mental vs. Depressions-1929-United States).

Subject searching allows you to look for categories of information. When a library record for an item is created it is given at least one subject heading, usually several. These are based on a pre-defined (controlled) vocabulary so that all items about the same subject are organized and searchable together. While this usually gives a list of very relevant results, the words chosen as subject terms are not always intuitive or obvious.