When entering a search in most databases, a user can select results ranking by relevance or date. All records found by the search are ranked but only the top 1,000 records are available for use.
In WorldCat, the default ranking is by "Number of Libraries." This means that records retrieved in a search are listed in descending order by the number of libraries holding the item. Commonly held items will be displayed first on the list of results
When viewing the results of a search that found between 2 and 500 records, a user can sort the records by one or more data fields. The fields available for sorting vary by database.