Research is often an iterative process. Conducting your research will give rise to new ideas. When researching library resources or a web search engine, you will need to experiment with different search strategies as you develop your searches, locate relevant resources, and identify additional keywords to use that best represent the aspects of the topics you are researching.
Boolean operators are a set of commands that can be used in almost every search engine and database, including Omni, an article index such as Medline and search engines such as Google Scholar. The most popular Boolean commands are AND, OR, and NOT. Boolean operators can help save you time because they can improve the relevancy of your search results and make your searching more efficient.
Other commands include parentheses, truncation, and phrases.
Using the Boolean command AND in your search tells the search engine to give you results that contain all of the words you have entered
E-cigarettes AND teenager*: only those results that contain both E-cigarettes and teenagers will appear in your search results list.
Using the Boolean command OR in your search tells the search engine to give you results that contain any of the words you have entered.
teenager* OR adolescent*: any results that contain either teenagers or adolescents will appear in your results list.
Most library databases provide the option to select Boolean Operators on the Advanced search screen. Select the operator you want from a drop-down box between search boxes.
Before you start your research, consider developing a list of keywords that best describe your topic.
Thesauri, specialized dictionaries and encyclopedias are all useful resources for learning more about aspects of your topic and will give you synonyms, additional keywords and subject-specific terms that can be used in your searches.
Ensure that your keywords are kept together by surrounding phrases wtih quotation marks (" "). If you have a keyword that is more than one word, such as human rights, you would type "health promotion" into the search box to ensure the words social and marketing don't get searched separately.
In most databases, AND is assumed between each word, by using quotation marks you are ensuring that your keywords are kept together in their intended meaning.
An asterisk (*) may be used to specify any number of characters. It is typically used at the end of a root word, when it is referred to as "truncation." This is great when you want to search for variant endings of a root word.
For example: searching for program* would tell the database to look for all possible endings to that root. Results will include program, programs, programme, programmes, programming. Use the truncation symbol with caution.
Whenever you have more than one Boolean operator, such as AND and OR, in a search statement, it is necessary to separate them with parentheses. This is known as a "nested searching." Here's an example:
( E-cigarettes OR vaping) AND teenagers
Nested searching tells the database the proper order in which to search for the keywords. Operations enclosed in parentheses are performed first followed by the operators outside the parentheses.