You have to experiment with different search strategies when you are doing research. Sorry, there's just no way around it. Boolean Operators can help you save time because they can improve your search results, but it's important to know when and why to use each one.
For example, let's use the research question "Do soft drinks contribute to childhood obesity?" Most databases give you the option to select Boolean Operators on the search screen, so all you have to do is select the operator you want from a drop down box between search boxes.
Here's our advice:
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 "soft drinks" and "childhood obesity" so that both concepts appear in all of your search results. Searching with AND gives you fewer results.
Use OR when your key term has synonyms which different authors may use interchangeably. In this example, use it to link the synonyms "soft drinks" and "soda" so that you'll get results with either concept. Searching with OR gives you more results.
Use NOT when your research topic is often closely associated with another concept you do not want information about. In this example if you are researching soft drinks and childhood obesity, but do not want information about vending machines in schools link the key term "vending machines" to the other key terms with NOT so that you eliminate all results that include the unwated concept. Searching with NOT gives you fewer results.
Also called wildcards, this is the process of adding an '*' 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."
This is the process of keeping keywords together by surrounding with quotation marks (" "). So if you have a keyword that is more than one word, such as human resources, you will want to type "human resources" into the search box to ensure the words human and resources don't get searched separately.
Before you start searching, consider developing a list of keywords that best describe your topic.
Remember to think of synonyms or additional terms you know of -- and don't be afraid of using a thesaurus or encyclopedia to find more keywords if you are unfamiliar with a topic.
Here is an example of breaking down a topic into keywords:
Prisons (main keyword)