Keyword vs. Subject Searching
Keyword and subject searching methods are two widely used ways to effectively find items on your topic. They are usually offered to the researcher among other search options by any index, database, or online library catalog. There are important advantages to both methods; knowing how to use them and how they differ from each other will help you retrieve better, more accurate results.
What is keyword searching?
Keyword searching uses any words you can think of that best describe your topic. Keyword searches will be broad: title, source and contents of each item will be searched for your keyword(s). This is the reason your searches may retrieve too many, too few, or completely irrelevant items. That is why using this method is a good way to start your research process. A keyword search can be the first step on the way to finding subject headings appropriate to your topic and using them to get more relevant results.
What is subject searching?
Subject searching uses subject headings that come from a predetermined list of possible terms and reflect the content of the item. Most academic libraries use Library of Congress Subject Headings (LCSH) for Subject Search of their online catalogs. A subject search is more specific than a keyword search: it looks in only one field of each record - the subject field. Many databases use subject headings that are unique to that particular database. This controlled vocabulary allows for consistency of terms across the database. For example, Medline database uses MeSH - medical subject headings and CINAHL database also has its own unique headings. These subject headings can be found in the database's thesaurus. In the thesaurus subjects are often listed with broader, narrower, or related subjects. Using the database's thesaurus will help you identify most effective search terms.
Use both keyword searching AND subject searching to get better results:
- Start your search with keyword searching; use your own words that describe your topic best.
- After getting results, focus on the most relevant record(s), and among subject headings, presented in them; choose the most suitable ones for your topic. In some databases subject headings can also be called "terms" or "descriptors".
- Now is the time to turn to subject headings for your further search.