Subject Headings & Thesauri (a.k.a. let’s demystify some jargon!)

This week’s post offers us a glimpse into some of the rather confusing jargon of library research: subject headings, keywords, and database thesauri. While these terms sound rather boring and unhelpful, they actually refer to several strategies which can significantly assist you in the research process.

Let’s be honest: you probably never, or hardly ever, even think about ‘subject headings’ (or ‘subject terms’ as they are also called). Why would you? You likely wouldn’t even think to search this way unless you noticed the option when selecting a search field:

search fields

The difference between searching by subject and searching by keyword is all in the name.

  • When you use a keyword, you are searching for words in the work’s title, abstract, etc.
  • When you use a subject heading, you are searching for the subject of the work, regardless of the keywords used to describe it.

Imagine it this way. Let’s say you are doing some research related to supervisors in the workplace. There are a number of keywords which might describe someone in this position: supervisor, manager, boss, leader, and so on.  However, in a database, all of these keywords will be categorized under a single subject heading, such as ‘manager’.

Here’s a one-minute animation describing this difference for all of the visual learners (and cartoon watchers) out there:

OK librarian, why bother?  Well, subject headings are a wonderful tool to use during initial research. If you are having trouble thinking of synonyms, or you just want to be sure to catch every document within a certain category, searching for its subject term will help you do that.  Likewise, there are subject terms which can help you find certain types of documents such as case studies or reviews. And, since subject headings refer to the ‘aboutness’ of an article, they typically return highly relevant results.

OK librarian, how am I supposed to think of subject terms?  That is nearly impossible. Seriously, some subject headings use quite unnatural language or appear bizarrely complicated (depending on who created them).  This is where the database thesaurus swoops in to the rescue!


Image by Lights Camera Click. CC license here.

Dinosaur humor aside, a database thesaurus is designed to help you discover subject terms related to your topic. Many database vendors, such as ProQuest and EBSCO, offer links to a thesaurus on their advanced search page.  Once there, you can search for a term in order to figure out its preferred subject heading.

Here’s an example. I opened a thesaurus in ProQuest and searched for ‘case study’. The thesaurus returned a result for ‘case studies’ which included a note stating: “used to identify articles that focus in-depth on a single company or organization’:



When I use ‘case studies’ as a subject term, this will ensure that all of my results have been officially indexed as case studies by the database creators.  Now, I can combine this subject term with a keyword or two related to my topic:



On the results page, instead of having to sift through each document to determine whether or not it is a case study, I already know that I am only viewing documents officially indexed as such.

As mentioned, this thesaurus strategy works great both for discovering terms related to your subject and for specifying certain types of documents.

Remember, you can also discover subject terms after conducting a keyword search. Imagine you did a keyword search on employee feedback and found a great article. You can click on its ‘citation/abstract’ to view which subject terms were used to describe it.  This way, you can consider adding one or more of these terms to future searches:



Want to see a video example of how keywords and subject terms alter the results you will find? Check out our thesaurus video here, or find it by following the ‘quick tip videos’ tab at the top of the screen.

As ever, happy searching!