PSYC 3980: Research Design

AND, OR & NOT are Boolean search operators. You can use these words to direct a database how to search for your concept terms.

OR

• Creates a union search - all terms join to form one group.
• Creates a larger set of results - broader searches
• Works well for different spellings of the same word
• Works well for different types or examples of the same concept

You can combine AND, OR, and NOT to build very complex searches by grouping each concept in parentheses.

(surcalose OR aspartame OR saccharin) AND headaches

You can use OR with dissimilar concepts, but watch out for the relevancy and result size. This example would need refining, but could be a useful starting point.

(cats OR dogs) AND "household pets" 

AND

• Combines concepts to find an area of overlap
• Creates a smaller set of results - more narrow searches

NOT

• Is an exclusionary search that can be extremely effective when combined with a field search
• Good for eliminating false hits
• Good for eliminating terms that may broaden the search
• Good for eliminating the wrong types of articles

In the following example, I want to look at different types of therapy that cats and dogs are used for, but I'm not interested in therapy to remove phobias about dogs or cats. Also, I happen to know that authors Samuel and Elizabeth Corson do research on drug therapy used for aggressive animals. That would be the wrong direction, so I want to exclude their articles.