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Class Stems

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  • The class stem in a classification number consists of letters and numbers including in this order:

    • Letter author symbols for the parent issuing body.
    • Numbers indicating subordinate offices, followed by a period.
    • Numbers designating category classes, series, or serial title.

    The class stem generally ends in a colon. Some class stems extend past the colon and include additional letters and numbers followed by a slash. See Continuing Resources for examples of class stems ending in a slash.

    Letter Author Symbols

    The first letter or letters in the classification number represent the department or independent agency issuing the publication. Each department or independent agency has a unique letter or combination of letters assigned to it. 

    There are slight deviations due to the limits of the 26-letter alphabet. Generally, the letter or letters chosen as the author symbols correspond to the first letter of one or more keywords in the name of the agency. Some examples:

    A Agriculture NCU National Credit Union Administration
    C Commerce P U.S. Postal Service
    D Defense PREX Executive Office of the President
    E Energy S State
    HE Health and Human Services SBA Small Business Administration
    HS Homeland Security SI Smithsonian
    ITC International Trade Commission T Treasury
    J Justice TD Transportation
    LC Library of Congress V Veterans Affairs

    The X and Y designations used for classifying publications from the United States Congress are exceptions. The boards, commissions, and committees established by an Act of Congress or under authority of an Act of Congress, not specifically designated in the Executive Branch of the Government, are grouped under Y 3. Series designations are handled differently in the X and Y classes and are discussed in Congressional and Legislative Branch Publications.

    Consult the List of Classes of United States Government Publications Available for Selection by Depository Libraries for a current, complete list of letter author symbols; classification numbers for Federal agencies, bureaus, and departments; alphabetic listing of Government authors; and list of item and class stems.

    New Agency Classes

    When a new agency or department is established, it is important to determine the enabling authority so that the agency is assigned its correct place in the classification system. Conduct research to determine the enabling authority; this may be a public law, an Executive order of the President, or a departmental directive.

    If a publication appears without an issuing office name, search the publication for a letter of transmittal, preface, or foreword which gives information or an agency contact to help identify the publication. Within GPO, jacket number is another source for determining the issuing agency. 

    In the online environment, agency may be determined by the internet address or URL:


    af.mil indicates the official military website of the United States Air Force (USAF)

    acc indicates the USAF Air Combat Command

    Ultimately, it may be necessary to contact the agency directly.

    Joint Publications from Different Agencies

    A joint publication is one issued jointly by two or more agencies. If this is the case, all of the agency names will be listed on the publication. Classify the publication under the first agency listed.

    A revised edition of a joint publication should be classified with the original if both agencies are issuing the revision, regardless of the order of the agencies listed. If only one of the agencies issued the revision, it should be classified under the revising agency regardless of where it was classified originally.

    Publications Prepared by One Agency for Another

    If a publication is prepared by one agency for another, determine which agency is the actual publisher of the publication in question, and classify under that agency. In most cases, the agency for which the publication was prepared is the issuing agency; however, on occasion the preparing agency will publish it. This can generally be determined by the title page or cover format. As with many classification questions, the Catalog of U.S. Government Publications should also be searched to discover any established patterns.

    For example, the Department of Interior’s U.S. Geological Survey may prepare a publication for the Commerce Department. If the Commerce Department issued the publication, that is where it should be classified. 

    Sometimes, publications are produced under contract from a Federal agency. These may be issued by a contractor and do not appear to be Federal publications. If this is the case, use the class number for the agency that issued the contract. This may be found in the preface, title page, technical report page, or similar location.

    Sometimes publications issued by one agency appear on the website of a different agency.  In that case, the publication should be classed under the issuing agency. For example, an older State Department document can be found on the website of the Central Intelligence Agency; classify the document under State.

    Serials with Changing Publishers

    If the publication is a serial and the printed order of the agencies changes with later issues, retain the original class if the first agency is still listed as a publisher. If not, then a new class number may need to be established for the new agency publisher.

    Joint Publications Issued in Series

    A publication may carry one or more series statements from different federal agencies. The presence of a series does not necessarily determine the class number of a joint publication. Depending on the number of publications in the series, it may or may not have its own unique class. Do not conclude immediately that the series class is where the publication belongs.

    First, determine the issuing agency to be used in the class (generally the first agency listed, with possible exceptions for revised editions). After the proper issuing agency has been determined, classify in the series appropriate to that agency. It may be the first or second series listed, but it must agree with the issuing office.

    For example, a joint publication is issued by NASA (National Aeronautics and Space Administration) and the U.S. Army Research Laboratory; the publication contains a series statement by each agency. The publication is a part of the NASA Technical Memorandum series, and has the series numbering 2012-217280; the publication also belongs to the ARL-TR series, and has the series numbering 4757. In this instance, in light of NASA being the agency presented first, the publication is classed under NAS 1.15, the class number for the NASA technical memorandum series.

    If a double series is issued routinely by two agencies, and the publications are not consistent in presenting the agency and series in uniform order, classify the publications in one class consistently.

    A joint publication may carry only one series. If the agency listed first is not the agency associated with the series, then the series is not used in the class. The publication should be classified in a general class under the agency selected as the issuing agency. Search the Catalog of U.S. Government Publications to discover any established patterns. For more information on series and serial classification, see Monographic Series and Continuing Resources.

    Subordinate Offices

    First and Second Levels

    A number designating a subordinate office follows the letter designation of the parent issuing body. The numbers, prior to the period, identify subordinate offices one level below the parent agency. 

    • The parent agency, always designated by the number 1, is the first-level office.
    • The number 1 is always used for the office of the secretary of a department or the administrator of an independent agency.
    • The 1 class should be used for any publication carrying only the department or agency name with no subordinate bureau listed.

    The numbers 2 through 99 are used for subordinate bureaus, administrations, offices, and so on, immediately below the level of the head of the agency. The classification number does not generally include designations for offices below the second level:

    A 1. Agriculture Department (including Secretary’s Office)
    A 13. Forest Service
    A 62.  Risk Management Agency
    A 88. Agricultural Marketing Service

    In some classes, such as Defense, 3 digits are used before the period to designate second-level subordinate bodies. The use of 3 digits was necessary for the Defense Department because of the considerable number of subordinate issuing agencies:

    D 1. Defense Department  
    D 101. Army Department  
    D 102. Adjutant General’s Office (Army)  
    D 201. Navy Department  
    D 202. Naval Air Systems Command  
    D 301. Air Force Department  
    D 302. Judge Advocate General of Air Force  

    Assignment of Classes 

    New classes are assigned in chronological order, determined by the order in which publications are received and a new class is required.

    New subordinate or level 2 classes should be assigned as offices are established and publications are issued. The next higher number should be assigned beginning with number 2 after the author symbol.

    Third and Fourth Levels

    Some agencies of the Federal Government are complex in their organization, with various smaller bureaus, divisions, or other types of offices encompassed within the agency structure. Classes are created for third and fourth level offices to enable assignment of class numbers to the smaller offices within these large agencies, especially those with numerous publications.

    An office immediately subordinate to a second-level office is a third-level office. Fourth-level offices are immediately subordinate to third-level offices.

    Classes are broken down to the third and fourth levels by using 100 and 1000 numbers after the parent agency’s assigned number, after the period and before the colon. Distinguishing between third and fourth levels is not as clear as distinguishing between first and second levels. The decision on how far to go in the breakdown depends upon how small a breakdown is necessary for clarity:

    C 1. Commerce Department (level 1)    
        C 55. National Oceanic and Atmospheric Administration (level 2)  
        C 55.  
             .100’s National Weather Service (level 3)  
             .200’s National Environmental Satellite, Data, & Information Service (level 3) 
             .300’s National Marine Fisheries Service (level 3) 
             .400’s National Ocean Service (level 3) 
     HE 1.  Health and Human Services Department (level 1)
        HE 20.   Office of Public Health and Science (level 2)  
        HE 20    
             .3000’s National Institutes of Health (level 3)  
               .3150’s National Cancer Institute (level 4)
               .3200 to.3249 National Heart, Lung, and Blood Institute (level 4)
               .3250's National Institute of Allergy and Infectious Diseases (level 4)
             .3600’s National Library of Medicine (level 3) 

    Subordinate Offices Issuing Limited Publications: Slash Numbers Added

    Third and fourth level offices not expected to issue many publications may be treated the same as series or category classes. In these cases, a slash and a number are added after the number for the subordinate office.

    A 13. Forest Service
    A 13.66/: Pacific Northwest Research Station
    A 13.66/1: Research progress…
    A 13.66/2: General Publications
    A 13.66/12: Handbooks, Manuals, Guides
    A 13.66/16: Science Update

    A 13.66 is reserved for publications of the Pacific Northwest Research Station. As new classes are needed for publications from this office, new slashes are used.

    HE 20.400: Substance Abuse and Mental Health Services Administration
    HE 20.427:   Center for Mental Health Services (General Publications)
    HE 20.427/2: Consumer Information Series
    HE 20.427/4: Mental Health United States
    HE 20.427/9: National Child Traumatic Stress Network (General Publications)

    HE 20.427 is established for general publications of the Center for Mental Health Services. As new classes are needed for other publications from this office and its subordinates, new slashes are used.

    New Classes for Third and Fourth Level Organizations

    When a new subordinate office is established: 

    • Determine the name of its parent organization and how the office fits into the agency organization.
    • Determine how many levels there are between the new organization and the departmental secretary or independent agency administrator.
    • Use the letter of the agency, the number for the first level breakdown followed by a period, then a 100, 200, or 300 class as appropriate, followed by a colon.

    If not many publications are expected, consider assigning a series class rather than a subordinate agency class. If the agency is expected to issue many publications and has many smaller offices, all of which will produce many publications, you may use 1000 numbers to differentiate between offices. There are very few cases where this will be necessary.

    Joint Publications from Different Subagencies

    When a joint publication (not in a numbered series) carries two equally subordinate bureaus under the same department, classify the publication under the bureau listed first. If three or more equally subordinate offices are named, disregard and classify the publication under the parent agency. Consult the United States Government Manual and similar resources that cover the organization of the Federal Government when making this decision.

    To determine which one is the parent agency, and if subordinate offices are equally subordinate, contact the issuing agency or investigate online.

    Name Changes and Reorganizations

    Agencies can be inconsistent in naming their subordinate offices, and frequent name changes can pose a challenge.

    A name change does not necessarily demand a class number change. If the agency’s function and position within the parent organization remain the same, the class number will remain the same. When it appears that a name has changed, the agency should be contacted to verify the nature of the change. Any updates to that effect will appear in WEBTech Notes and the List of Classes.

    Reorganizations within an agency present other problems. Sometimes offices and functions are moved from one subordinate office to another. It is important to note the issuing office on each publication in order to determine whether a reorganization has taken place that will affect the class. The class number must be changed when an agency is moved from one parent agency with one author symbol to a second parent agency with a separate author symbol.

    HS 5.100: Federal Emergency Management Administration (FEMA)
    (FEMA was previously classed under FEM)
    HS 5.200: U.S. Fire Administration (USFA)
    (USFA was previously classed under FEMA as FEM 1.100)

    Documents classed prior to agency reorganizations are not reclassed.

    Reorganization is a particular problem in serials when the name of the serial remains the same, the publication looks the same, and the numbering follows along logically, but the issuing office has been transferred to another bureau or office. In those cases, the class number must be changed when the issuing body has moved to another agency.

    It is important to change the class with the first issue carrying the name of the new department or bureau. Always check the parent agency of any publication being classified to confirm that the subordinate office class is still correct; in this way, you can avoid changing class numbers retroactively.


    Superintendent of Documents Classification Guidelines

    Introduction to the Classification Guidelines
    The Classification System: A Brief History
    Structure of the Classification Number
    Sorting in SuDocs Order
    Example of a SuDocs Sort
    Class Stems
    Letter Author Symbols
    New Agency Classes
    Joint Publications from Different Agencies
    Publications Prepared by One Agency for Another
    Serials with Changing Publishers
    Joint Publications Issued in Series
    Subordinate Offices
    First and Second Levels
    Assignment of Classes
    Third and Fourth Levels
    Joint Publications from Different Subagencies
    Name Changes and Reorganizations
    Category Classes
    Most Frequently Used Category Classes
    .1 - Annual reports
    .2 - General publications
    .8 - Handbooks, manuals, and guides
    .11 - Maps and Charts
    .12 - Posters
    Less Frequent Category Classes
    .3 - Bulletins
    .4 - Circulars
    .5 - Laws
    .6 - Regulations, rules, and instructions
    .7 - Press releases
    .9 - Bibliographies and Lists of Publications
    .10 - Directories
    .13 - Forms
    .14 - Addresses
    Cutter Numbers
    Cutter Table and Its Use
    Filing Order for Cutter Numbers
    Slash Numbers
    Selecting Cutter Words
    Words to Avoid when Cuttering
    Sets With a Collective Title
    Foreign Language Editions
    Numbers in Titles
    Cuttering Acronyms and Initialisms
    Cuttering: Geographic Topics
    Cuttering Related Documents Covering the Same Subject but Different
    General Subjects and Geographic Terms
    Cuttering Geographic Terms Using Personal Names
    Cuttering Multi-Part Geographic Names
    State Cutter Numbers
    State Cutter Numbers Table
    Additions to Book Numbers
    Year Format
    Dates for Revised Editions
    Punctuation in Dates or Date Ranges
    Volume, Part, Chapter, and Section Numbers
    Volume Number and Date: Which Comes First?
    Volume Number Followed by Date
    Date Followed by Volume Number
    Words and Abbreviations
    Foreign-language Publications
    Multiple Word Phrases in a Suffix
    Multiple Versions of a Publication
    Corrected Copies of Numbered Volumes
    Standard Abbreviations and Words
    State Abbreviations
    Classes by Publication Type
    Preliminary, Draft, and Final Reports
    Preprints and Separates
    Summaries and Executive Summaries
    Electronic Products
    Sets with Multiple Publication Types
    Monographic Series
    Identifying a Monographic Series
    Assigning New Series Classes
    Series Related to Existing Classes by Subject
    Structure of the Series Class
    Departmental Series vs. Bureau Series
    Series Book Numbers
    Series Numbering
    Unusual Series Numbering
    Series Numbering and Revised Editions
    Numbering system changes
    Two series on one publication
    Series number vs. Agency control number
    Letters and Phrases Appearing on Publications
    Volumes, Parts, or Sections
    Publications Which Are Not Serials or Series
    Multipart Monographs versus Series
    Other Situations
    Continuing Resources
    Identifying a Continuing Resource
    Integrating Resources
    Assigning New Continuing Resource Classes
    Works Related to Category Classes
    Works Related to Existing Classes by Subject
    New Classes to Reflect Changes for Existing Serials
    Serials within Series: Separate Class Approach
    Serials with a Constant Series Number
    Cuttering a Serial or, When Not to Establish a New Class Stem for a Serial
    Serials within Series: Cuttering Approach
    Publications of Short Duration
    Other cases for Cuttering
    Serials Designation
    Number 1 for First Month Appears Annually
    Date incorporated in Series Number
    Volume and Number
    Annual Publications
    Semiannual Publications
    Publications Issued Three or More Times a Year
    Variations in Publication Cycles
    Release Date vs. Coverage Date
    Special Issues of Serials
    Frequently Revised Monographs Cataloged as Serials
    Presidential Publications
    Presidential Committees and Commissions
    Presidential Commissions vs Presidential Initiatives
    Permanent Agencies Reporting to the President
    Vice President of the United States
    Congressional and Legislative Branch Publications
    Y 4. - Congressional Committee Publications
    Constructing the Committee Designation
    Reorganized Committees and Name Changes
    Y 4. Committee Print or Y 1. Report?
    Joint Hearings
    Publications Prepared by One Committee for the Use of Another
    Individual Book Numbers
    House Book Numbers
    Numbered and Unnumbered Documents in One Class
    Senate Book Numbers
    Cutter Numbers
    Multipart Works
    Errors in Numbering on Publications
    Y 1.-: - Congress as a Whole, House and Senate as a Whole
    Individual Book Numbers
    House and Senate Documents and Reports
    Y 1.1/2: - U. S. Congressional Serial Set
    Y 1.2/5: - United States Code
    Boards, Commissions, and Independent or Temporary Committees Established by Congress
    Boards, Commissions, and Committees Established within the Executive Branch
    Executive Branch Independent Agencies with Limited Duration or Publishing Output
    Y 3. - Boards, Commissions, and Independent or Temporary Committees
    Agency Designations
    Category and Series Designations
    Related Series or Subjects
    Individual Book Numbers
    Y 3.2: - Limited Boards, Commissions, and Independent Committees
    Y 4.2: and Y 4.3: - Select and Special Committees (As Appointed)
    Y 9. - Speeches
    Y 10: and Y 11: - Subordinate Offices
    X 1.1: - Congressional Record
    XJH: and XJS: - House and Senate Journals
    Y and X General Issues
    Serial Publications
    Star Prints
    U.S. Participation in International Organizations
    Cartographic Resources
    Category Classes for Maps and Charts
    General Rules
    U.S. Geological Survey Maps
    Map Reference Numbers
    Northwest (NW) Quadrant
    Northeast (NE) Quadrant
    Southwest (SW) Quadrant
    Southeast (SE) Quadrant
    Edition Date
    Bureau of Land Management Maps
    U.S. Forest Service Maps
    Revision Dates
    National Ocean Service Nautical Charts
    Map Types
    Classification Guidelines for Digital Reproductions
    Classification by Type of Digital Reproduction

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    Questions on the GPO-specific practices outlined in the guidelines should be submitted via askGPO. Please indicate "Classification Guidelines" in the subject area.