Constructing a Search Statement

Identifying Keywords
Subject Searches

Computers do not "think; they don't understand the context for information you need, or the subtle nuances of human language and thought.  Computers are literal -- they  process commands based on the keystrokes you make.  In the same way, databases retrieve search results based on the words that you enter.  Learning how to identify correct terms and phrases for your topic is essential for conducting successful searches.

Identifying Keywords

The first step is to identify terms that describe each of the main concepts for your topic.

For the topic The Influence of Advertising on Incidents of Anorexia, the two main concepts would be:

advertising and anorexia

Using the topic Entrepreneurial Trends in the Hispanic Community, the most important concepts are:

Hispanic and entrepreneurs

• Narrow a topic that's too general.
  For example, a paper on the entire Civil Rights Movement would cover overwhelming amounts of information, while a study of the Civil Rights Movement Effects in Alabama would be manageable.
• Broaden your specific topic (place it in its broader context) if you find too few sources dealing with it.
  While you may not find entire books about the Battle of Marathon, you would find information about that battle in many history books on Ancient Greece.
• Focus on one specific aspect or central concept of the subject that you want to address.
  For example, aromatherapy might be a focus drawn from the larger subject of alternative medicine.

Remember to limit your search statement to essential words.

Few search tools attempt to make sense out of entire sentences entered as a search. Trim database searches down to essential words.

• A search can be complex and contain multiple terms, but it shouldn't contain unnecessary words. Omit pronouns, articles, adverbs and conjunctions (common words such as of, an, the and so on).
  
• Be alert when using OR and AND as search terms in any database. These words most often serve a specific function as Boolean operators, and are used to combine search terms -- for example, you might search for information about brothers AND sisters.

An effective basic keyword search statement for our previous sample topic (The Influence of Advertising on Incidents of Anorexia) would be:

advertising AND anorexia

To search for Entrepreneurial Trends in the Hispanic Community, use:

Hispanic AND entrepreneurs

Think of synonyms for search terms.

To identify terms for the main concepts of your topic, you often need to think creatively about synonyms, plurals and related words when conducting keyword searches. Using a sample topic The Negative Effects of Bovine Growth Hormone (BGH) on Cows, the main concepts are BGH and cows.  In order to find as much information as possible about cows, it would be reasonable to: 

• Try synonyms and plurals: cows, cattle, bovine, dairy cattle
• Try broader terms if you don’t find enough information: female livestock, bovidae
• Try narrower terms if you find too much information: Holstein, Guernsey

Searching for phrases can be tricky.

Some databases automatically search multiple words together as one phrase:

Spanish cooking = searches the exact phrase "Spanish cooking"

• If your results are unexpectedly few, it may be that your words are being searched as a phrase, and this exact phrase seldom appears in the database. In this case, repeat the search using AND between search terms.
  
  Workplace AND communication = searches the words workplace AND communication in any order, found anywhere in the database entries.
  
  
• In some databases and search tools (such as Google), AND is automatically implied between words. If your search results are surprisingly few, an implied AND may be breaking your phrase into individual search terms. You may need to re-submit your terms as a bound phrase search by using quotation marks to enclose the phrase.
  
  For example, you would search for the phrases "Bovine Growth Hormone" or "acid rain"

Keyword Searching allows you to:

• Combine search terms using OR and AND (Boolean operators), as in:
  advertising AND anorexia
• Construct more complex search statements by using parentheses to group terms.  For example, to find information about cows and Bovine Growth Hormone, you can use AND and OR in a single search:
  (cows OR cattle) AND "Bovine Growth Hormone"
• Use truncation (also known as a wildcard search, usually indicated by the * symbol) to search for any ending variation of a word, including plurals.  For example:
  universit* = will find results for university as well as the plural form, universities
  comput* program* = will find results whether the database uses the terms computer, computers, or computing, and program, programs, or programming

For more about Boolean, parenthetical and truncation searching, link to our Ramsey Library Research Guide to Boolean Searching.

Almost all electronic databases have a special keywords index that makes searching easier.  It's helpful to use a keyword search when you don't know specific titles, exact subject headings, or if you need to find contents of a book, such as stories in an anthology.  Keyword searches are recommended for cutting edge or newly popular topics, and for interdisciplinary topics or abstract concepts that cannot be adequately expressed by one single subject heading.

Subject Searches

In addition to a keywords index, most databases used for research also have a subject index that you can search for items on a particular topic.  Each entry in most databases is assigned one or more descriptive terms, or subject headings.

Though it's generally a good strategy to begin with keyword searches, there are definite advantages to subject searching:

• The sample topic animal welfare might also be described with such terms as humane treatment of animals, animal neglect, or protection of animals.  But when searching in the library catalog database, you wouldn't need to search for each of these terms in order to find all the information for this topic.  A single subject search for animal welfare will retrieve all the listed information.

• When a subject heading is used, it doesn't matter if a book with the title Bulls and Bears is really about the stock exchange.  A subject search for stock exchanges will find it.

Tip: The Library of Congress subject classification system used in the library catalog makes it possible to shelve all books about a specific topic in one place, and to shelve books on similar, related subjects in the same area of the library.  So when you find an appropriate book for your topic, be sure to browse the shelves around it for further information about your subject. 

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This page created by Janet Ferguson. Last updated 18 July 2005. Comments to the Library Web Team.

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