When you are doing research you will need to experiment with different search strategies. Boolean Operators can help save you time because they can improve your search results and make your searching more efficient. It's important to know that Boolean Operators are the underlying logic in library databases including Omni, article indexes and even search engines such as Google Scholar.
In Google Scholar, the Boolean Operators are available from the Advanced Search. Most library databases provide the option to select Boolean Operators on the Advanced search screen, so all you have to do is select the operator you want from a drop down box between search boxes, as with the example below from the ProQuest database International Bibliography of the Social Sciences.
Boolean Operator: AND
Use AND when your research topic has more than one key term that must be present in all of your search results. In this example, use it to link the key terms art and activism so that both concepts appear in all of your search results. Searching with AND gives you fewer results.
Boolean Operator: OR
Use OR when there are other terms that could also be used to describe the topic, including synonyms, related terms or words and phrases that have similar meaning. In this example, use OR to link art and aesthetic, and to link activism and protest, so that you'll get results with either concepts. Searching with OR gives you more results.
Boolean Operator: NOT
Use NOT when you want to exclude results that contain a particular word, phrase, or topic, or when your research topic is often closely associated with another concept you do not want information about. Using NOT will eliminate all search results that include the unwanted concept. Use NOT sparingly, if at all, as it could exclude results that are ultimately relevant. Searching with NOT gives you fewer results.
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.
Here is an example of breaking down a topic into keywords:
Prisons (main keyword)
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 "human rights" into the search box to ensure the words human and rights 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.
Truncation, also known as using a wildcard, is the process of adding an asterisk '*' to the end of a root word to get different variations on the word.
For example, doing a search on child* in a database would search for: child, children, childhood, childlike, or any other word that begins with "child."