George Mason University

Keyword Searching vs. Subject Searching

When searching the Library catalog for information on a subject, you can search by keyword (similar to how you would conduct a search in an online search engine like Google) or by subject heading. Use this page to determine the best strategy for a particular search.

Keyword Searching Subject Searching
Natural language - may search for any term or group of terms Pre-defined “controlled” vocabulary- must search for assigned subject headings
Familiar Not always intuitive
Searches all fields in catalog record Searches subject and/or descriptor fields only
Flexible - can combine terms

Less flexible

May yield irrelevant results Subheadings can help to focus results
May not yield all relevant results Results are usually relevant to topic

Keyword searching is a type of searching you are probably already familiar with. It is how you would typically search web search engines like Google. You think of words or phrases relevant to your topic and enter them in the search box. When searching the library catalog, your keywords and phrases are searched for in all of the fields of the catalog record. It is important to remember that because we are using natural language, the word you use to describe a subject may not be the same word used by all of the authors in the field.

Keyword Search when...

  • Your term is jargon, very new, or very distinctive.
  • You do not know the exact title or author of the item.
  • A variety of terms describe the topic (e.g. Ecology of fish in Potomac River)
  • You want to retrieve information by grouping two or more synonyms or terms (e.g. dogs OR canines; adolescents OR teenagers)
  • More than one discipline or topic is involved (e.g. statistics AND agriculture)
  • You want to exclude documents which are not about your topic (e.g. depression NOT great)
  • You don't know the subject heading. (Try a keyword search first, then look at the subject headings and use the appropriate one(s) for your next search)

How to search by keyword in the Mason library catalog

  • The library’s catalog allows you to search with keywords in several different ways. Single term Phrase – phrases such as “public relations” should be search enclosed by parentheses
  • Combining terms with AND, OR, and NOT
  • Combining (terms OR words) with parentheses
  • Access the library’s catalog search page, and highlight keyword in the list under Find Results in: Enter your search term(s) in the search box.

Subject searching is a type of searching that allows you to look for categories (or subject headings) instead of keywords. Subject terms are searched for only in the subject field. When the catalog record for an item is created it is assigned at least one subject heading. These subject headings are based on a pre-defined vocabulary in which all items determined to be about the same subject are given the same subject heading regardless of the term used by the author. A drawback of many of these pre-defined vocabularies is that the words chosen are not always the most intuitive or obvious choices.

Subject Search when...

  • You are looking for information on a broad topic.
  • You are looking for information about something, someone, or someplace (books about Mark Twain, not those written by him)
  • You want to locate resources about your topic, even those in which the topic is not explicitly expressed in the catalog record, except for in the subject headings assigned to them.
  • Your topic is poorly defined. Try a keyword search first, and then search for the subject headings you found.
  • You are looking for information that may be represented by a term that has many meanings and can occur in various contexts (e.g. “management”). Browse the "subject search results" list to help narrow or define your topic.

How to search by subject in the Mason library catalog

If you know the subject heading, access the library’s catalog search page, highlight subject heading in the list under Find Results in: and enter your search term(s) in the search box. If you don’t know a subject heading for your topic, try doing a keyword search first. Take a look at the record of an item that seems to best represent what you are looking for and review what subject headings are listed. The subject headings are listed in the catalog record next to the heading Subject(s).

Each of these subjects is hyperlinked and will take you to a list of headings where you can choose to see all of the titles which have been assigned the same subject heading by clicking on the number in the column Titles.

*Some content adapted from the University of Alaska Fairbanks

For more assistance with subject searching, Ask a Librarian.