Google's Help page has information on what Google is doing with words - they call it "looking for alternates" and we know it as stemming and word variants. Google is the most advanced in automatically looking for other combinations and forms. If you find it is biasing your results put a + directly in front of the word you want to control. Eg evaluate will pick up evaluating and evaluation. If you want only evaluate enter +evaluate.
Google may also have updated its page on Advanced Search, especially related to alternate words.
Certainly the Advanced Search form has been expanded to show more options.
Posted by Gwen at March 12, 2008 03:57 PM