With the increasing availability of digital reproductions of older U.S. Government publications, GPO has developed procedures for assigning SuDocs classification numbers and depository item numbers to these publications as they are added to the Catalog of U.S. Government Publications (CGP). Many of these digital reproductions represent publications that were never previously distributed through the Federal Depository Library Program (FDLP). Others represent legacy publications that were distributed in a tangible format, such as print or microfiche.
GPO assigns SuDocs classification numbers and depository item numbers to all publications disseminated through the FDLP. Publications within scope of the Cataloging and Indexing Program (C&I) but not the FDLP receive a SuDocs classification number and no depository item number.
As noted in The Classification System: A Brief History, the SuDocs classification system was developed between 1895 and 1903 and groups publications together based on the publishing agency. Depository item numbers, which were developed after 1923, are used by Federal depository libraries to select publications they wish to receive at their library. However, depository item numbers did not appear in the Monthly Catalog of U.S. Government Publications until the early 1940s.
GPO staff will conduct research to determine if a publication is an unreported publication (not previously identified for the FDLP or C&I) or if it has been previously distributed in a tangible format to libraries in the FDLP. If a publication has been distributed in a tangible format, additional research will be conducted to determine the exact SuDocs class and depository item number, if any, assigned to the tangible version. If required, a SuDocs class number may be assigned to an unreported publication.
Classification by Type of Digital Reproduction
| Type of Publication | Status | SuDocs Number | Item Number | MARC 500 Note |
| Digital reproduction of a previously distributed publication | SuDocs and item number are still active | Same as tangible version | Same as tangible version | |
| SuDocs and item number are inactive | Same as tangible version | Same as tangible version | ||
| SuDocs number but no item number; distributed prior to 1940 and no item number assigned at time of distribution | Same as tangible version | No item number is included in the bibliographic record | 'Distributed to Federal Depository Library Program (FDLP) libraries prior to 1940. No FDLP item number available.' | |
| Digital reproduction of an unreported publication | Falls under active SuDocs stem and item number | Active SuDocs stem used and appropriate suffix assigned | Item number of SuDocs stem included in the bibliographic record | |
| Falls under inactive SuDocs stem and item number | Inactive SuDocs stem used and appropriate suffix assigned | Item number of SuDocs stem included in the bibliographic record | ||
| Falls under inactive SuDocs stem but predates item number | Inactive SuDocs stem used and appropriate suffix assigned | No item number is included in the bibliographic record | "Publication pre-dates Federal Depository Library Program (FDLP) item numbers. No FDLP item number has been assigned." | |
| Unreported publication does not fall under existing SuDocs stem | New SuDocs stem created and appropriate suffix assigned | No item number is created if the agency is no longer active | If no item number assigned, note should read: "Agency is no longer active. No Federal Depository Library Program (FDLP) item number has been assigned." | |
| Item number created if agency is still active |