How do I use subject headings?

A note: Using subject headings may seem complicated in the beginning, but they do help to save you time in the long run.  They are especially helpful when you are researching a topic over a longer period of time.  See this blog’s previous post  “What is a subject heading” for more information, or visit the Beryl Ivey Library for assistance at any time. Please note that not all databases categorize their articles with subject headings, though, so it’s important to also know how to use keywords to research.

To research using subject headings, first you need to look them up using a database’s “thesaurus”.  Here’s how you do this for journal articles:

  1. Make sure you understand your topic. Write down some keywords and the different concepts your topic covers.
  2. Log into a database that would cover your topic (i.e. if my topic is “psychology”, the database PsycINFO is a good choice). If you don’t know which database to choose, check the Program Guide pages on Western Libraries’ website.
  3. Look for a link that says “Thesaurus” or “Descriptors” or “Subject Headings.”  This will bring you to the list of standardized subject headings for that particular database.  [In PubMed, it’s called “MeSH Database” (Medical Subject Headings Database)].
  4. Start searching the thesaurus for the list of subject headings on your topic.  Make sure to explore all angles of your topic.
  5. Make a list of the appropriate subject headings you can use to search.  In some cases, there may be more than one subject heading that would work (i.e. “women” and “female” may both be subject headings.  Another example could be “teaching” and “instruction”).

Once you have your list of subject headings, you can use these to search for articles within that database.  I’ve included a screenshot of PsycINFO below: here, you can see that they allow you to select subject headings as a way to search.  To search using PsycINFO’s subject headings, I just change the drop down menu and enter the list of subject headings. You can also select the link for “Look up Subjects” to see if it an official subject heading that this database uses. This can be helpful when looking for additional synonyms for your topic.


While most databases come up with their own list of subject headings, some use standardized systems.  Our library catalogue, for example, uses the Library of Congress system.  This means that the same subject headings in our Shared Catalogue would work in other university library catalogues that use LC.  PubMed, meanwhile, uses a system called MeSH (Medical Subject Headings) which can be found in a number of other medical databases as well, such as Medline.

A warning: if you’re searching for articles using Summon, you may see the limits of “Subject Terms” along the left of your results page.  These may help to limit your search, but they are not standardized terms like the ones discussed above.  Since Summon works like Google, with computers in charge of creating the list of resources, subject heading searches won’t work.

What is a subject heading? Why should I care?

Librarians love organizing things.  A lot. One product of this love is subject headings.  In more technical terms, these are standardized words assigned to a concept.

Using subject headings is a more advanced way to research as they help to reduce the amount of “garbage,” or irrelevant results, that come up.  This is because subject headings are assigned to an article or a book by a person, rather than a computer.  Subject headings are also assigned based on the topic of the article, rather than just the words that appear in the text.

For example, let’s say I was doing a project on teaching methods.  There are many words I can type into the library catalogue or online databases that would bring up words on this topic: teaching, teaching methods, teachers, instruction, instruction methods, education , education methods, educate, educating, educators…

Who knows which word in the list above is the “best” word, that will bring up the most relevant articles to my topic? A function of subject headings is to take this guess work out of researching.  Rather than typing out ALL those variations on teaching methods, I can use a subject heading that would cover all of these concepts.

Some online databases, therefore, have a list of standardized words that you can use to search instead of using keywords. This list includes definitions, too, so you know which word is the best one. Using our example from above, even if an article never says the word “instruction” in the text but has been assigned the subject heading “instruction”, then it will appear when you conduct a search using this subject heading.

Subject headings must be looked up first, though, before you start researching.  (See “How do I look up subject headings” for more information on how to do this.)  This process takes some practice, but it’s worth the effort!

If you’d like to try using subject headings on your own, a good place to start is in Western’s Shared Library Catalogue.  Most university libraries use Library of Congress Subject Headings, and Western is no different.  Each item (i.e. each book) is assigned subject headings by Western’s cataloguers, and you can find these if you scroll to the bottom of any record in the catalogue.  Know that this will only work in the catalogue and not in Summon, which works like Google rather than traditional databases.

For more information (for our science students) you can also see the Western Libraries video tutorial on using subject headings.