082 - Dewey Decimal Classification Number

"The Dewey Decimal Classification (DDC) system is the world’s most widely used way to organize library collections. The DDC constantly updates to enable better discovery across any topic in multiple languages. Because the DDC is easy to use, you can increase the visibility of your materials quickly and efficiently." -- OCLC website

The DDC was invented by Melvil Dewey in 1872 when he was a 21-year-old student assistant in the library of Amherst College. His classification draws from Sir Francis Bacon’s classification of knowledge as well as library classification systems designed by William Torrey Harris and Natale Battezzati. Dewey’s promotion of his classification and emphasis on centralization of cataloging efforts set in motion a new era of “library economy.”

DDC classification numbers are found in the 082 tag of the MARC record which is a repeatable tag because sometimes an item has had more than one DDC number assigned to it. The indicators tell you about the creation of the classification number in the tag.

• The first indicator tells you which edition of the DDC  was used: the full edition (0), the abridged edition (1), or some other edition which is specified in subfield 2 (value=7). 
• The second indicator tells you who created the number: Library of Congress (0) or someone else (4).
  

Subfield a (which may appear multiple times in a single 082 tag) contains the classification number (indicating what the thing is about) and subfield b (when it is there, which it often isn't) contains the item portion of the call number (the who of the creation of the thing).

For example, the Dewey classification for Franklin Pierce by Peter A. Wallner  is found in the OCLC record as 

082 0 4  ǂa 973.6/6/092 ǂa B ǂ2 22

In this example there are 2 subfields a. The first one is a Dewey number for an historical item with a biographical aspect to it. The slash marks (segmentations) are points at which it would be reasonable to truncate the number. The second subfield a is a B for biography which is a classification option some Dewey libraries use.  

The indicators tell us that this classification was assigned using the current full edition of the DDC (0) and was assigned by a library other than the Library of Congress (4). Subfield 2 is present, because it is common (and helpful) practice to indicate the edition of the current DDC when you assign a number because "current" is a moving target. This book came out in 2004 when the DDC was in the 22nd edition (published in 2003). The current edition today is the 23rd which came out in 2011. 

There are numerous variations of the format of the subfield 2, depending on the edition being used (electronic or paper, in different languages, different edition dates, etc.). In older records you commonly saw just the edition number. Current practice favors a more extensive subfield 2, like these examples: 

082  00           ‡a813/.6‡223/eng/20230630
082  04           ‡a839/.694‡qCaOONL‡223/eng/20231103

The rules you need to interpret more complex entries are explained in BF&S.

If you want to keep up with the evolution of the DDC, following the Dewey Blog is a good option.

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Since this is the last Tuesday of the month it is time for the April 2024 Tuesday Tags Review Quiz.

This is a 5-question self-check that will give you a chance to see how much you have learned about MARC tags this month (or where you may want to go back and re-read).