Subject headings are essentially agreed-upon terms that refer to concepts. The Library of Congress Subject Headings are considered a worldwide standard, so they're a good place to start.
| Photography | Daguerrotype | Museums and photography |
| Art and photography | Portrait photography | Photography museums |
| Black-and-white photography | Stereoscope | Critical theory |
| Color photography | Photography— Equipment and supplies | Postmodernism |
| Composition (Photography) | Photographic art galleries |
As you can see, there is some overlap between keywords and subject headings, and some words and phrases can be used as either. However, keywords and subject headings function very differently within a catalog or database. Subject headings are essentially tags used to organize records according to topic, while keyword searches generally look for the words to appear anywhere within the full text or the item's record.
If you would like to learn more about LCSH, check out this tutorial:
Certain fields and databases have their own controlled vocabularies, or thesauri. For example, the database, Art & Architecture Complete, has its own controlled vocabulary.
Once you've opened the Art & Architecture Complete database, scroll past the search fields until you see tabs that say "Filters, Search Options, Publications, and Subjects." Click on the "Subjects" tab to search the thesaurus.
These subject headings are arranged hierarchically, so when you open a term you will often see broader terms, narrower terms, and related terms linked. These thesauri can help you identify preferred terms, or the agreed-upon language to refer to a subject.
Broader terms are less specific, these can help if you're not retrieving many results with your initial search strategy.
Narrower terms can help filter search results if you retrieve too many, or results that are not directly related to your subject.
If you explode narrower terms, the search will include the main search term (CRAYONS) and any narrower terms (OIL pastels and PASTEL crayons)
Related terms are terms that exist in a different hierarchy, but may be applicable to your search.
Used for shows examples of plain-language or other terminology that can be used to describe the subject or topic, but is not preferred term.
It's never a bad idea to change up your search strategy to help find additional sources. Using subject headings in addition to keyword searches can help you find additional resources, but how do we use subject headings?
To search by subject, you will need to adjust the search entry field or utilize the subject field notation in your search string.
In most databases, subject field notation will be SU, but there are some variations.
In the RIC catalog, you will see "Subject (su:)" and "Subject phrase (su=)"
Subject (su:) allows you to search for words that appear in subject headings
Subject (su=) allows you to search for phrases that appear in subject headings
In general, you can default to using the "Subject (su:)" field as it behaves more predictably than the "Subject (su=)" field, even with phrases if you enclose the phrase within quotation marks. However, as always, it never hurts to switch up your search strategies - just pay attention to how different strategies affect the number and quality of your results.
One of the most useful ways to utilize subject headings is to mine the metadata of sources you have already located. In any database or search tool, if you see that subject headings are hyperlinked, you can click on the subject heading to retrieve results of other items indexed with the same heading.
Let's say that we have already located a source that we want to use in our research. If we open the item's record in the RIC catalog, we can see its metadata, including its subject headings.
If we click on the subject heading, "Photography in historiography," it will launch a new search with the string "su: Photography in historiography."
