Lexis and Westlaw Order of Operation Chart

When constructing Westlaw and Lexis searches, it will help to know in what order the terms are being processed. The terms are not read simply from left to right, but according to an order of operations. The librarians at the University of Illinois put together this handy CHART showing the order in which operations are processed. On Westlaw, phrases in quotes are read first, then in the following order: OR, /n, /s, /p, AND, and lastly NOT (but not, %). Of course, you can alter the order of operation by putting parts of the search in parentheses.

For example:
negligen! and unnatural /3 accumulation /s snow or ice

Would be read: ( (unnatural /3 accumulation) /s (snow or ice)) and negligen!

The Westlaw search engine

1. puts snow or ice together
2. puts unnatural /3 accumulation together
3. puts unnatural /3 accumulation /s snow or ice together
4. then adds on “and negligen!”