Definitions of the following collection depth indicators or levels are taken from Guidelines for a Collection Development Policy Using the Conspectus Model International Federation of Library Associations and Institutions, Section on Acquisitions and Collection Development, 2001. (By following this link you will be leaving the NRC-CISTI web site.) The levels were developed under the auspices of the Association of Research Libraries and reflect electronic forms of information and access/ownership issues in collection development.

1. Minimal Level

Collections that support minimal inquiries about this subject and include:

• A very limited collection of general materials, including monographs and reference works.
• Periodicals directly dealing with this topic and in-depth electronic information resources are not collected.

The collection should be frequently and systematically reviewed for currency of information. Superseded editions and titles containing outdated information should be withdrawn. Classic or standard retrospective material may be retained.

2. Basic Information Level

Collections that serve to introduce and define a subject, to indicate the varieties of information available elsewhere, and to support the needs of general library users through the first two years of college instruction include:

• A limited collection of monographs and reference works.
• A limited collection of representative general periodicals.
• Defined access¹ to a limited collection of owned or remotely-accessed electronic bibliographic tools, texts, data sets, journals, etc.

The collection should be frequently and systematically reviewed for currency of information. Superseded editions and titles containing outdated information should be withdrawn. Classic or standard retrospective materials may be retained.

3. Study or Instructional Level

Collections that provide information about a subject in a systematic way, but at a level of less than research intensity, and support the needs of general library users through college and beginning graduate instruction include:

• An extensive collection of general monographs and reference works and selected specialized monographs and reference works.
• An extensive collection of general periodicals and a representative collection of specialized periodicals.
• Limited collections of appropriate foreign language materials, e.g., foreign language learning materials for non-native speakers or foreign language materials about a topic such as German history in German.
• Extensive collections of the works of well-known authors and selections from the works of lesser-known authors.
• Defined access to an extensive collection of owned or remotely-accessed electronic resources, including bibliographic tools, texts, data sets, journals, etc.

The collection should be systematically reviewed for currency of information and for assurance that essential and important information is retained, including significant numbers of classic retrospective materials.

4. Research Level

A collection that contains the major published source materials required for doctoral study and independent research includes:

• A very extensive collection of general and specialized monographs and reference works.
• A very extensive collection of general and specialized periodicals.
• Extensive collections of appropriate foreign language materials
• Extensive collections of the works of well-known authors as well as lesser-known authors.
• Defined access to a very extensive collection of owned or remotely accessed electronic resources, including bibliographic tools, texts, data sets, journals, etc.

Older material that is retained and systematically preserved to serve the needs of historical research.

5. Comprehensive Level

A collection in a specifically defined field of knowledge that strives to be exhaustive, as far as is reasonably possible (i.e., a "special collection"), in all applicable languages includes:

• Exhaustive collection of published materials.
• Very extensive manuscript collections.
• Very extensive collections in all other pertinent formats.
• A comprehensive level collection may serve as a national or international resource.

¹ Defined access means more than simply providing patrons with access to the Internet and one or more Internet browsers. Defined access refers to menu options on the library or institution's home page, etc., which link the user to owned or remotely accessed electronic resources selected by the library with the needs of its patrons in mind. The level of defined access changes according to the level of the collection, e.g., from limited to extensive to very extensive access to collections of electronic information.