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ARHS Library & Instructional Materials Center: Search Strategies

Using Keywords

Keywords are the words you decide to use in your search, or the words related to your topic or appearing in your search results.

EXAMPLE: Your research topic is the impact of the media on perceptions about immigration. The keywords are "media," "perceptions," and "immigration."

A keyword searches all of the fields in the database record, including title, abstract or summary, and subjects or descriptors. The search looks for each of the keywords wherever they appear, either by themselves or in different orders. This can result in too many or too few results, and it may retrieve irrelevant results.

Word and Subject Searching

Subject Searching:
Every item in a database is assigned at least one subject heading. (In some databases, the word "descriptor" is used instead of "subject heading.") These subject headings (or descriptors) come from a predetermined list of possible terms and reflect the content of the item. This means that someone actually reviewed an item to determine its contents, and then selected one or more subject headings/descriptors to describe it. Additionally, a subject search is a very specific kind of search, looking in only one field of each record -- the subject field.

If you know the subject heading/descriptor which matches your topic, try a subject search. You'll be guaranteed to find a list of items whose content matches your topic.  If you don't know the specific subject heading/descriptor, searching by subject becomes trickier. In these cases, trying a word search is a better strategy.

Word Searching:
Word searching, sometimes called full-text searching or keyword searching, looks for your search term or terms in many parts of an item record. A word search often looks at words in an item's title, abstract or notes, and subject field. (This is much different from a subject search which looks at only one field-- the subject/descriptor field.)

Word searching is a mixed blessing. On one hand, it is extremely helpful if the subject/descriptor is unknown. Using your own search terms, you can retrieve lists of materials on a topic without having to know that specific subject/descriptor heading. On the other hand, it often brings back many useless materials, which are sometimes called "false hits." Since the word search looks for your terms in so many fields, it can pick up the term in the title, abstract, notes, or other fields. An examination of the subject heading may reveal that an item is not useful for your research

Research Hint:
Often, a successful search strategy uses both word searching and subject searching:

    1. Do a word search to find materials on your topic.

    2. Examine the list of materials to locate one whose content seems to match your topic.

    3. Once you have this one item on the computer screen, look at the subject/descriptor field to determine which subject/descriptor heading best matches your topic.

    4. Do a new search for material on your topic. This time, try a subject search for the subject/descriptor heading that looked promising.

Boolean Operators

Now that you've created a list of search terms and keywords, you need to organize them into meaningful search statements.

When you search electronic databases (such as a library catalog or an electronic index ), you cannot just type in your research question ("What risk factors are associated with polluted drinking water?").  Unlike some big, commercial search engines like Google, the electronic databases won't understand what you are looking for. You need to speak in a way they will understand.

One concept to formulate effective search statements is to use Boolean Operators (AND, OR, NOT) to connect your keywords and concepts, like this:

AND - narrows a search; Use to combine key concepts, for example: Water AND Pollution.

OR - broadens a search; Use to add concepts, for example: Pollution OR Water.

NOT - excludes search term(s). Use to eliminate a concept, for example: Water NOT PollutionUse sparingly!

Truncation and Wild Cards

Truncation
Most research databases allow for a symbol to be used at the end of a word to retrieve variant endings of that word. This is known as truncation. For example, in Education Abstracts, the "$" is used as a truncation symbol. By placing this at the end of a root word, such as work$, you will retrieve all words beginning with that root (work, worker, workforce, workplace, etc.).

Be careful using truncation! If you want to retrieve items about cats, don't truncate the word cat. If you do, you will also retrieve cataclysm, catacomb, catalepsy, catalog, etc., etc. It's best to use the boolean operator "or" in these instances (cat or cats). In some databases, such as Lexis-Nexis Academic, the database will automatically search for simple plurals.

Wild Cards
Some databases allow for wild cards to be embedded within a word to replace a single character. For instance, in Education Abstracts, you can also use $ within a word to replace characters. For example, comp$tion finds composition, competition, computation, etc. You can also limit the number of characters that the wild card symbol represents. For example, theat$2 finds theater or theatre, but not theaters, theatrical, etc..  Truncation comes in handy when you want to pick up both American and English spellings.  For instance, behavi$or retrieves behavior and behaviour.

Research Hint
The symbols used for truncation and universal characters often vary from database to database. To determine the symbols in the database you're using, check the online help screens or ask a librarian.