0 - OUT OF SCOPE: The library does not collect in this subject.
1 - MINIMAL LEVEL: A subject area in which few selections are made beyond very basic works. A collection at this level is frequently and systematically reviewed for currency of information. Superseded editions and titles containing outdated information are withdrawn.
1a - MINIMAL LEVEL, UNEVEN COVERAGE: Few selections are made and there is unsystematic representation of subject.
1b - MINIMAL LEVEL, EVEN COVERAGE: Few selections are made, but basic authors, some core works, or a spectrum of ideological views are represented.
2 - BASIC INFORMATION LEVEL: A selective collection of materials that serves to introduce and define a subject and to indicate the varieties of information available elsewhere. It may include dictionaries, encyclopedias, access to appropriate bibliographic databases, selected editions of important works, historical surveys, bibliographies, handbooks, and a few major periodicals. The collection is frequently and systematically reviewed for currency of information.
2a - BASIC INFORMATION LEVEL, INTRODUCTORY: The emphasis at this level is on providing resources that introduce and define a subject. A collection at this level includes basic reference tools and explanatory works, such as textbooks; historical descriptions of the subject's development; general works devoted to major topics and figures in the field; and selective major periodicals. The introductory level of a basic information collection is only sufficient to support patrons attempting to locate general information about a subject or students enrolled in introductory level courses.
2b - BASIC INFORMATION LEVEL, ADVANCED: At the advanced level, basic information about a subject is provided on a wider range of topics and with more depth, there is a broader selection of basic explanatory works, historical descriptions, reference tools, and periodicals that serve to introduce and define a subject. An advanced basic information level is sufficient to support students in basic courses as well as supporting the basic information needs of patrons in public and special libraries.
3 - STUDY OR INSTITUTIONAL SUPPORT LEVEL: A collection that is adequate to impart and maintain knowledge about a subject in a systematic way but at a level of less than research intensity. The collection includes a wide range of basic works in appropriate formats, a significant number of classic retrospective materials, complete collections of the works of more important writers, selections from the works of secondary writers, a selection of representative journals, access to appropriate machine-readable data files, and the reference tools and fundamental bibliographical apparatus pertaining to the subject. At the study of instructional support level, a collection is adequate to support independent study and most learning needs of the clientele of public and special libraries, as well as undergraduate and some graduate instruction. The collection is systematically reviewed for currency of information and to assure that essential and significant information is retained.
3a - STUDY OR INSTRUCTIONAL SUPPORT LEVEL, INTRODUCTORY: This subdivision of a level 3 collection provides resources adequate for imparting and maintaining knowledge about the basic of primary topics of a subject area. The collection includes a broad range of basic works in appropriate formats, classic retrospective materials, all key journals on primary topics, selected journals and seminal works on secondary topics, access to appropriate machine-readable data files, and the reference tools and fundamental bibliographical apparatus pertaining to the subject. This subdivision of level 3 supports undergraduate courses, including some advanced undergraduate courses, as well as most independent study needs of the clientele of public and special libraries. It is not adequate to support master's degree programs.
4 - RESEARCH LEVEL: A collection that includes the major published source materials containing research reporting, new findings, scientific experimental results, and other information useful to researchers. It is intended to include all important reference works and a wide selection of specialized monographs, as well as a very extensive collection of journals and major indexing and abstracting services in the field. Pertinent foreign language materials are included. Older material is usually retained for historical research and actively preserved. A collection at this level supports doctoral and other original research.
5 - COMPREHENSIVE LEVEL: A collection in which a library endeavors, so far as is reasonably possible, to include all significant works of recorded knowledge (publications, manuscripts, other forms), in all applicable languages, for a necessarily defined and limited field. This level of collection intensity is one that maintains a "special collection"; the aim, if not the achievement is exhaustiveness. Older material is retained for historical research with active preservation efforts.