How Boolean Operators Work
Credit: Furman University
Using Boolean Operators
One way to formulate effective search statements is to use Boolean Operators. Boolean Operators can be used to narrow or broaden your search results when you are searching an electronic database. The three Boolean Operators are AND, OR, and NOT.
AND - Narrows a search by connecting two or more concepts. This search finds items that contain endangered and birds.
OR - Broadens the search by adding concepts. This search finds items that contain either endangered or items that contain birds.
NOT - Excludes search terms to eliminate a concept. The search endangered NOT birds finds items that contain endangered but eliminates items that contain birds.
Too Many or Too Few Results? Refine Your Search
Too Many Search Results ?
- Find better search terms or keywords. Think of terms that are more specific and modify your search.
- Add more search terms. Start with a smaller number of keywords and then add more terms to refine your search.
- Use limiters. Limiters such as date and format will give you more targeted results.
- Do not use OR. Using OR between terms will search for all instances of each term.
- Notice the default search options. Databases often search in the title, author, abstract and subject fields. Be specific and search for the terms in just the title or subject field.
- Narrow down your topic. Your topic may be too broad so think about a more focused aspect of the topic.
For example, students --> college students --> freshmen
Too Few Search Results ?
- Try a database on your topic. Search in a database that specializes in a certain subject because it covers the subject discipline in greater depth. Use Databases by Subject or consult a Research Guide created by a UConn subject librarian for help.
- Broaden your topic. Did you start too narrow and specific? Is the topic too new? Think about broader search terms on the subject.
- Change your search terms. Consider similar or related terms.
- Use fewer search terms. Start with a smaller number of keywords and add more as needed.
- Use fewer limiters. Limiters such as date or format can cause you to have too few results. Remove one or more limits to expand your search to include more results.
- Check your spelling. Unlike Google, research databases often do not suggest a correct spelling.
- Use OR with synonyms.
- Use wildcard [usually a question mark] or truncation [an asterisk] to include additional variations of your search terms. Consult the help section of the database for more specific information.
Adapted from DIY Library Project, Portland State University Library
Narrowing a Search in a Database
A brief [~2.5 min] tutorial on limiting general database results.
Narrowing Your Search
Most databases give you the option of using limits to narrow your search results. A few of the most commonly used limits are Full Text, Scholarly [Peer-Reviewed] Journals and Date. Others may be language, document type and publication/source type. The options will vary by the database.
Controlled Vocabulary
[Credit: University of Washington Libraries]
Advanced Searching
Controlled Vocabulary
Many databases use controlled vocabulary. Controlled vocabulary is an organized arrangement of words and phrases used to index content and/or retrieve content through browsing or searching. Subject headings, subject terms, thesaurus terms, and descriptors are examples of controlled vocabulary. Different disciplines use different controlled vocabularies.
Reading the Search Results
[click on the image above to see the complete record]
Tips to consider whether or not a citation record is useful :
- times cited
- do the keywords & descriptions seem useful
- is it timely [is that important for your project?]
- consider both date and relevance sorting options
- is it a scholarly source [is that important for your project]
- you may have different keywords between scholarly & popular sources
Does it relate in any way to your original topic?
Using your research log to keep track of new keywords, subject terms, and sources will help you to keep track of your research.