- Whether the search terms appear anywhere in the WorldCat bibliographic record. (Note: Search terms appearing in the title, author, or subject field are ranked highest.)
- Proximity of the search terms to each other.
- The number of libraries that report owning the item.
- How recently the item was published.
Although the default is to sort the results by library and relevance, you can select Sort by: author, title, date, or relevance only (regardless of library location).
Source: WorldCat Local Help, 6/24/2011.