Our default search operator is AND. Last time I looked, about 82% of users used AND, 13% used exact phrase matching, and the remaining 5% were about evenly split between OR and proximity matching. A casual scan of the search terms people use suggests that multi-term searches are usually in the form of names (like "Louis Riel") or concepts ("Murder in the Yukon", "History of Hudson bay company"). I don't think I've ever noticed anyone searching using several synonyms, where OR searching might actually be useful. William Wueppelmann Canadiana.org (formerly Canadian Institute for Historical Microreproductions) http://www.canadiana.org Ross Singer wrote: > What do you think is more appropriate (and intuitive) for a search > engine if the user gives no boolean, "and" or "or"? > > I guess my question is, assuming it's a keyword search, and the user > types in "institute paper science", would it be more appropriate to > default to "institute AND paper AND science" or "institute OR paper OR > science". > > I'm just sort of curious what other people's take on this might be. > > Thanks, > -Ross. >