When you have a long search, sometimes it becomes important to control the "order of operations."
Nesting refers to putting a section of a search in parenthesis so that the computer processes that part first. Typically, we'll use nesting to group our synonymous terms we've linked with OR.
(teenager OR adolescent)
AND
(ACL OR anterior cruciate ligament )
Try the following searches in a database of your choice:
1. blood pressure AND pregnancy OR maternity
2. (blood pressure AND pregnancy) OR maternity
3. blood pressure AND (pregnancy OR maternity)
Do you get the results you expect? Which search do you think is correct?
As a human being, we can see that pregancy and maternity refer to similar populations, and so the researcher likely intended to find articles that mentioned either pregnancy or maternity along side the term blood pressure.
However, a computer cannot tell which terms are meant to be grouped together and will simply read the results from left to right. In this case, we want search #3, blood pressure AND (pregnancy OR maternity).
