The rules are designed to meet the following objectives:
The catalog should be an efficient instrument for ascertaining (in this priority order):
1. Which expressions of a particular work, specified by its creator and title, or, if the work does not have a single creator, its title alone, the institution contains or can provide access to
or
2. which works by a particular creator the institution contains or can provide access to
or
3. which works on a particular subject the institution contains or can provide access to
or
4. which works in a particular genre or form the institution contains or can provide access to
or
5. whether the institution contains or can provide access to a specific expression or manifestation of a work
To be an efficient instrument, the catalog must be designed to provide the user with efficient indexes and efficient displays that achieve the above objectives. In order to create efficient indexes and efficient displays in computer-based catalogs, the data must be adequately encoded to support such indexes and displays.