Parentheses and Precedence

ProQuest interprets your search from left to right. However, it observes an order of precedence with respect to operators.

OR has precedence over AND

ProQuest gives the OR operator precedence over the AND operator. This means, if you enter cat AND dog OR pet, ProQuest interprets the search as cat AND (dog OR pet). All the documents your search finds will contain the word cat, and will also contain the word dog, the word pet, or the words dog and pet.

Using Parentheses

You can change the order of precedence for your search by using parentheses. Surrounding terms with parentheses forces them to be evaluated together. To change the search in the previous example to find documents that contain both cat and dog within the same paragraph or documents that contain just pet, add parentheses: (cat AND dog) OR pet.

Precedence

Precedence is not limited to operators. It extends to cover anything that you can include in a search, including fields, operators, and phrases.

The following list details the order of precedence (from highest to lowest) that ProQuest observes when interpreting your search:

1. A phrase
   "big yellow dog" OR pet becomes
   (big yellow dog) OR pet.
2. OR
   cat AND dog OR pet becomes
   cat AND (dog OR pet).
3. PRECEDE BY
   cat AND dog PRE/2 pet becomes
   cat AND (dog PRE/2 pet).
4. WITHIN
   cat AND dog W/2 pet becomes
   cat AND (dog W/2 pet).
5. AND with a specified search field
   cat AND Sub(dog) OR pet becomes
   cat AND (Sub(dog) OR pet).
6. AND NOT or AND NOT with a specified search field
   cat AND NOT dog AND pet becomes
   cat AND NOT (dog AND pet).
7. WITHIN DOC
   cat W/DOC dog AND pet becomes
   cat W/DOC (dog AND pet).