Chapter 8: Gathering Research and Establishing Evidence
NOT Operator
The operator NOT is used when you want to search for the first term and to exclude items that contain the second term. Teaching is a very broad term that is often qualified by broad levels such as primary, elementary, intermediate, secondary, higher, or, post-secondary. While you may want to specify a level that you want to look for by trying a search such as teaching AND secondary, you could decide to qualify or narrow the search by excluding a level that you are not interested in by using the NOT operator. The following Venn diagram illustrates the concept teaching as shown by the circle in green on the left. The concept post-secondary is shown by the light grey-coloured circle on the right.. While there is some overlap with both concepts shared by some articles and books, when you use the NOT operator in the example of teaching NOT post-secondary, you exclude those hits that had both teaching AND post-secondary (not shown). That is why the desired set on teaching resembles a circle with a piece removed. [Remember that the NOT operator is sometimes called ANDNOT. The Help information in a database will give you directions if you can simply use NOT or have to use ANDNOT as your Boolean operator.]
Example of a Venn diagram using the NOT operator: teaching NOT post-secondary