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 exact 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.
physical activity → "physical activity"
Affordable Care Act → "Affordable Care Act"
Ernest Hemingway → "Ernest Hemingway"
Use AND to connect keywords and narrow results.
Finds results where both keywords are present in the search fields.
You will not want to use every term you have identified. Remember, every time you add a word you will narrow your search and receive fewer results.
→ "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.
Finds results where either keyword is present in the search fields.
This is an ideal to search strategy to use with synonyms. This can be particularly effective when combined with an AND term.
→ "physical activity" OR exercise
→ elderly OR "aging adults" OR "older adults"
→ (running OR cardio) AND obesity
Use NOT to eliminate keywords from results.
Eliminates results that have a keyword present in the search fields.
This is helpful to eliminate topics that would likely appear in your search results, but that aren't relevant to your specific research topic.
→ exercise NOT "weight lifting"
→ obesity AND walking NOT running
→ exercise OR "physical activity" NOT teenagers