Represented are the detailed set of data structures relevant to the categorization of information, terminology, and definitions employed in the design of the library statistical data base. The data base, or management information system, provides administrators with a framework of information and standardized data for library management, planning, and decision making; communication and comparison between libraries, and reporting to external agencies and organizations. The organizational divisions of the document are divided according to the functional areas used in the conceptual approach of the system: environment, the overall resources, and programmatic activities of the library. Environmental data represent the first major section, which is categorized into subsections for public and academic libraries. The library resources section is divided into four subsections: collection, human, financial, and facility resources. The third section is the program data and is divided into the following sub-sections: financial, personnel, facility, activity, and user measures. The final section lists outcome and performance measures. Some sections of the document are said to be at an early stage of development and changes and refinements will be dictated through practical applications of the system. Appended are a list of the data sources of definitions and data elements and a reprint of the Higher Education General Information Service (HEGIS) taxonomy used to categorize instructional programs and disciplines; an index is included. (Author/JPF)