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Information Literacy

Boolean Operators

With the right search technique you can specify your information searches to find just the right information you need.

When searching for information in databases you need Boolean operators to combine search words with each other. In some databases you must type the operators manually and in some the operators are automatically. When using Google, the operators are automatically included, unvisible for the user. The operators may have different names in other search programs: logical operators, Boolean logic or search commands.

The most commonly used operators are;

  • AND
  • OR
  • NOT

Use parentheses ( ) in the search phrase to clarify the search when you use several different operators, for example. The search engine will look for the search phrase inside the parenthesis first, and then combine the search phrases with each other.

Watch the tutorial to see examples:

Using Boolean Operators

Use the operator AND when you want all your search words to appear in the search result. The operator AND limits the search result.

Example:

  • You need scientific articles on the topic marketing tourism services. You use the scientific database Academic Search Complete. The combination of the search words marketing AND tourism search for publications where both search words occur:

The operator OR is used when we want one of the search words to occur in the search result. OR expands the search result.

Example:

  • You need to find more information on marketing tourism services. By adding synonyms to the search word marketing you will find hits with either one or several synonyms together with the search word for tourism, (marketing OR advertising OR branding) AND tourism:

The operator NOT is used when we want to exclude a word from the search result. You have to be careful when using this operator, since it may exclude useful information by mistake. The operator NOT limits the search

Example:

  • You want to exclude information on social media for marketing tourism services and choose to add the operator NOT followed by the search word "social media" to your search:

Phrase Search

With a phrase search the search engine will look for the search words in the exact same order as you have typed them in the search field. Phrase search can be used in both databases and in search engines when your search word consist of two or more words. Phrase search can also be used in Google. Use quotation marks " " around your search words to get a result answering to the exact phrase.

For example:

  • the search phrase donald duck can turn up a reference or a web page where a person called Donald Pizzarro describes his delicious duck recipe for Canneton à l’Orange. Instead, write "donald duck" to find information on Donald Duck

More examples:

  • "academic writing" instead of academic writing
  • "human resource management" instead of human resource management
  • "information security" instead of information security

Truncation

You can leave out part of a search word, which is called truncating. If you do not truncate search words, part of the result may be omitted because the search engine looks for words in exactly the form they are entered into the search engine. This is an important point if you are looking for information in Finnish (because of different word endings). In English, words are often spelled differently in British and American English (e.g. behavior vs. behaviour).

Truncation is marked with a truncation character. The most common one is * (but also ?, # or $ are sometimes used). It is also often possible to exchange one or more characters in the middle of a word because of different spelling variations. As different databases use different signs, always check what sign a certain database is using. Truncation is done automatically in Google searches. Arcada Finna uses * as truncation character.

Examples:

  • the search word market* could give results on market, markets, marketing etc
  • the search word organi*ation could give results on organisation or organization etc
  • the search word *sonic could give results on subsonic, supersonic etc

Always consider carefully where to truncate a search word. If you cut it too short, it may turn up results that you are not interested in (emu*, for example, could turn up ’emu’, ’emulate’, ’emulsifier’, ’emulsify’, ’emulsion’ etc).

Too many or too few results?

Sometimes, an information search may give you a very large number of results, while at other times, you find no results at all. In addition, a search will often give you unexpected results that do not give you any answers to your information need.

Evaluate the success of your information retrieval by considering the following points:

  • Search words
    • is the search word misspelt?
    • are the search words too broad or too narrow? You can search for suitable search words in sources you have already discovered
    • could truncation be an option?
    • could phase search be an option?
    • should you use a thesaurus to find better search words?
    • have you used the boolean operators in the best way?
  • Information source
    • have you chosen the right database? Does it cover your field of interest? You need to gather information from several different information sources, no one single source is generally enough
    • you can specify and filter your search according to e.g. language, country or publication type

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