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  1. Home
  2. Superintendent of Documents Classification Guidelines
  3. Structure of the Classification Number

Structure of the Classification Number

  • Last Updated: November 15, 2024
  • Published: April 26, 2021

The SuDocs Classification Number consists of a class stem and a suffix. The class stem is a general designation used to bring related publications together. The suffix uniquely identifies a publication and differentiates it from all others classified under the same stem.

The suffix consists of a book number, and sometimes additions to the book number. For numbered publications, the book number is usually derived from the numeric designation appearing on the publication. For unnumbered publications, the book number is usually derived from a word in the title using a Cutter number.

A fundamental rule in SuDocs classification is that each publication is assigned a unique classification number. In cases where an identical number would apply, a word, abbreviation, or number is added to the book number to differentiate the two. If a publication consists of multiple parts or issues, each discrete piece receives its own unique extension to the book number.

A Superintendent of Documents classification number begins with a capital letter or letters representing a Government department or agency; capital letters are used for all letters in Superintendent of Documents classification numbers:

Example:
A  (Department of Agriculture)

The letters are followed by a number representing the agency as a whole, or a subordinate office. This is followed by a period:

Example:
A 13. (Forest Service)

After the period, there is a number designating the series or serial title, or category of the publication, followed by a colon:

Example:
A 13.150:  (Southern Research Station: General Publications)

In this example, A 13.150: constitutes the class stem. The class stem alone shows that the publication in this example is a general publication issued by the Department of Agriculture, Southern Research Station.

The letters and numbers after the colon represent the individual publication:

Example:
A 13.150:W 64  Wildflowers of the Savannah River Site

In this example, W 64 is the book number.

Spacing is critical for the proper construction of the class number. A space must be inserted between letters and numbers in the class number unless there is intervening punctuation.

Formatting examples:

Incorrect  Solution Correct formatting
A 93.2:AF8 Add a space between F and 8 A 93.2:AF 8
C 55.22/ 3:SE 1 Delete the space after the slash symbol C 55.22/3:SE 1
D5.317:616(717-5)A Add a space after D; before, after parentheses D 5.317:616 (717-5) A
D 101.11:9-2330-363-14 & P Remove spaces between 4&P D 101.11:9-2330-363-14&P
I 49.44/2: AS 3/4/2016 Delete the space after the colon I 49.44/2:AS 3/4/2016
  • Parentheses are the only exception to the spacing rule. One space must be inserted before and after a parenthesis, unless there is adjacent punctuation.
  • No spaces precede or follow symbols, such as the ampersand (&) or slash.
  • In classification numbers, roman numerals (I, II, III) should be converted to Arabic numerals (1, 2, 3).

Libraries can construct their own Superintendent of Documents classification numbers according to the principles outlined here. For documents falling in existing classes, find the class stem in the List of Classes. Add a Cutter number, date, or series number after the colon and an arbitrary designation such as “X” at the end to indicate that it is a locally assigned number.

Government publications are classified after they are received by LSCM; publications not received are not assigned classification numbers by LSCM.

Sorting in SuDocs Order

SuDocs classes are arranged alphabetically based on the leading letter(s). The number between the period and colon is a whole number (ex. HS 1.2: comes before HS 1.15:). After the colon, the hierarchy of sorting is as follows:

Example:

Date
Letters
Numbers
Word

In both the class stem and the suffix, an empty space will file before a space that has a letter or number (i.e. ‘nothing’ before ‘something’). The ‘nothing’ aspect includes spaces and punctuation, with the exception of the colon. This is illustrated in the following list with the example of Y 4.EC 7:S.HRG.110-646 preceding Y 4.EC 7:SA 9/2.

Example of a SuDocs Sort

A 13.2:T 73/4
A 93.2:N 95/3
A 93.73:76
A 93.73:89
A 93.73/2:62
C 13.58:7564
C 13.58:7611
HE 20.4002:AD 9/2
HE 20.4002:AD 9/5
HE 20.4002:F 94
L 36.202:F 15/2
L 36.202:F 15/2/980
L 36.202:F 15/3
Y 1.1/7:109-118
Y 1.1/7:109-131
Y 1.1/7:110-6
Y 1.1/7:110-20
Y 4.EC 7:C 73/7
Y 4.EC 7:C 73/10
Y 4.EC 7:S.HRG.110-646
Y 4.EC 7:SA 9/2
Y 4.EC 7:SCH 6
Y 4.EC 7:SE 2

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 Geographic Area
      • General Subjects and Geographic Terms
      • Cuttering Geographic Terms Using Personal Names
      • Maps
      • Cuttering Multi-Part Geographic Names
      • State Cutter Numbers
    • State Cutter Numbers
  • Additions to Book Numbers
    • Dates
      • 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?
    • 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
    • Corrections
    • Errata
    • Preliminary, Initial, Draft, and Final Reports
    • Reprints
    • 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 versus Agency Control Number
    • Letters and Phrases Appearing on Publications
    • Volumes, Parts, or Sections
    • Publications Which Are Not Series or Serials
      • Multipart Monographs versus Series
      • Other Situations
  • Continuing Resources
    • Identifying a Continuing Resource
    • Serials
    • 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
    • Date
      • Annual (and Less Frequent) Publications  
      • Semiannual Publications
      • Publications Issued Three or More Times a Year
      • Variations in Publication Cycles
      • Release Date vs. Coverage Date
    • Special Issues of Serials
      • Supplements
      • Indexes
    • 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
      • Joint Hearings
      • Publications Prepared by One Committee for the Use of Another
      • Individual Book Numbers
    • 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
      • Y 3. Boards and Commissions Outside the Executive Branch
    • Y 4.2: and Y 4.3: - Select and Special Committees (As Appointed)
    • Y 7.1: - Memorial Addresses
    • 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
      • Erratum/Errata
  • U.S. Participation in International Organizations
  • Cartographic Resources
    • Category Classes for Maps and Charts
    • General Rules
    • U.S. Geological Survey Maps
      • Coordinates
      • Map Reference Numbers
      • Northwest Quadrant 
      • Northeast Quadrant
      • Southwest Quadrant
      • Southeast 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
  • Superintendent of Documents Classification Guidelines for Specific Publications and Classes
    • A 13.28: - Forest Service OHV (Off-Highway Vehicle) Maps
    • AE 2.106/3: - Code of Federal Regulations (CFR)
    • I 53.11: - Pacific Northwest Recreation Map Series
    • S 1.1: - Foreign Relations of the United States (FRUS)
    • SI 8. - National Gallery of Art
    • Y 1.1/3: - The Constitution of the United States of America: analysis and interpretation: annotations of cases decided by the Supreme Court of the United States to ...
    • Classing Publications in ERIC (Education Resources Information Center) Database

Classification Guidelines Resources

Catalog of U.S. Government
   Publications (CGP)
govinfo
List of Classes 
Lost Docs
U.S. Government Manual
WEBTech Notes
Webinars and Webcasts

Superseded Guidance 
GPO Classification Manual (1993)
An Explanation of the
   Superintendent of Documents
   Classification System (1990)

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Please submit your questions about the Superintendent of Documents Classification Guidelines via askGPO by choosing the “Federal Depository Library Program” tile and selecting the category “Cataloging/Metadata (Policy and Records).

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