Boolean operators form the basis of database logic. You do not need to use them on sites such as Google, but they are a requirement for academic databases full of journals.
In short, Boolean operators connect your search words together to either narrow or broaden your set of results. You can combine multiple Boolean operators to create more effective searches.
The three basic boolean operators are: AND, OR, and NOT.
Use AND in a search to:
Use OR in a search to:
Use NOT in a search to:
Keywords are words or short phrases that represent the main ideas in your research topic or question.
In search engines such as Google, you can search using full sentences. However, the Library databases are not as smart as Google and do not understand full sentences, spelling mistakes or conversational language. This means that when you are searching, you need to break your topic into keywords instead - you have to consider the words that authors are using to write about a topic.
If you are writing an assignment on the impact of diet on child obesity, your key concepts would be: diet, child, obesity, child obesity.
For each key concept, try to think of as many similar or related words as possible. This can include synonyms, antonyms, and specific concepts within a topic. When you search for sources using a range of different keywords, you will find more and more search results that are relevant to your topic.
Once you have found your keywords, you can combine them using the Boolean Operators AND, OR and NOT, as described in another box on this page.
Truncation is a technique that broadens your search to include various word endings and spellings.
nurs* finds: nurse, nurses, nursing
child* finds: child, children, childhood, childbirth
manag* finds: manage, manages, manager, management etc.
midwi* finds: midwife, midwives, midwifery
Tip! Be careful not to truncate too soon.
e.g. leg* or comp* will retrieve too many false results
Some databases assume that words typed next to each other should be searched as phrases. However, many databases do not do this. Most academic databases automatically put a Boolean AND between your search terms: meaning that all the words used will be present in your search results, but they may not necessarily be adjacent to each other. When this happens, your search results may not be relevant to your topic.
To avoid this happening, you can use "double quotation marks" to keep words together when you search.
“living standards” OR “standards of living”