Once you have developed a list of keywords, you will need to start thinking about how to use them effectively in your search. If you regularly use search engines like Google, you may be accustomed to typing a question or sentence directly in the search box. While that may work, it will also inevitably find many erroneous, irrelevant, or unacceptable results. In other search tools, like the library catalog or databases, this type of searching will not work.
Instead, using what is called a search statement will help you best approach your research. You will use your keywords, in combination with phrase searching and specialized search words called Boolean terms, to develop this statement. Boolean terms (AND, OR, NOT) are used to either narrow or broaden your pool of results when used with multiple keywords. Boolean terms usually appear in all uppercase letters to distinguish them from the keywords. Some search tools require capitalized Boolean terms as well.
Enclose phrases, proper names, and titles with quotation marks. Adding quotations keeps all the words together so your search engine, database, or library catalog does not search for them as individual words.
Example:
physical activity → "physical activity"
Affordable Care Act → "Affordable Care Act"
Ernest Hemingway → "Ernest Hemingway"
Use AND to connect keywords and narrow results. Every term connected by an AND must be found in the results of the search tool.
In creating an AND search statement, you will not want to use every term you have identified. Doing so will produce a very limited pool of results, or no results at all. A better approach is to select terms for each facet or separate concept in your thesis, and then connect them with an AND. Try two or three of your strongest keywords linked together at a time. Remember, every time you add a word you will narrow your search and receive fewer results. If you have too few results, eliminate keywords or substitute others.
Examples:
→ "weight lifting" AND obesity
→ exercise AND health AND elderly
→ "physical activity" AND diabetes AND "aging adults"
Use OR to search with synonyms and expand results. With OR, you are telling the search system that you want information about either one idea or another. This is an ideal to search strategy to use with synonyms. This can be particularly effective when combined with an AND term.
Examples:
→ "physical activity" OR exercise
→ elderly OR "aging adults" OR "older adults"
→ running OR cardio AND obesity
Use NOT to eliminate keywords. Here you are directing the search system to ignore results including a particular word or phrase. This is helpful to eliminate topics that change the results. For example, if you want to know about manatees from around the word, but not Florida manatees specifically, you can search for "manatees NOT Florida" to eliminate any results that mention Florida.
NOT can be used in conjunction with AND or OR. Just make sure NOT comes after the keyword you want to include and before the keyword you want excluded.
Examples:
→ exercise NOT "weight lifting"
→ walking NOT running AND obesity
→ exercise OR "physical activity" NOT teenagers
*Some search tools use a minus sign (-) instead of NOT to eliminate keywords.