From 5214f5cc4d5862a42a2a87bb75cebf2e4020403e Mon Sep 17 00:00:00 2001 From: Ben Burwell Date: Tue, 11 Feb 2020 15:24:51 -0500 Subject: Add DDC post --- _posts/2020-02-11-how-dewey-decimal-works.md | 195 +++++++++++++++++++++++++++ 1 file changed, 195 insertions(+) create mode 100644 _posts/2020-02-11-how-dewey-decimal-works.md diff --git a/_posts/2020-02-11-how-dewey-decimal-works.md b/_posts/2020-02-11-how-dewey-decimal-works.md new file mode 100644 index 0000000..5fc73d4 --- /dev/null +++ b/_posts/2020-02-11-how-dewey-decimal-works.md @@ -0,0 +1,195 @@ +--- +title: How the Dewey Decimal Classification Works +--- + +The Dewey Decimal Classification (DDC) is widely used in libraries to organize +their collections. I think a lot of people have probably used the DDC to find a +book in a library, and a lot of people generally know how it works: number +ranges correspond to high-level topics, with more numbers in the middle to fill +in more specific subjects. You might be familiar with the table of main classes: + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
000Computers and general information
100Philosophy and Psychology
200Religion
300Social Sciences
400Language
500Math and Science
600Technology
700Art
800Literature
900History and Geography
+ +I've always been interested in how the rest of the digits were decided on, so I +decided to learn more! Surprisingly, it's a bit challenging to find references +on the DDC because it's actually sort of a proprietary system. It's managed and +published by the Online Computer Library Center (OCLC), and they're quite happy +to sell you the DDC or access to WebDewey for many hundreds of dollars. + +After some further digging, I came across an [online class on the Dewey Decimal +Classification][class] from the Nebraska Library Commission. It's three sessions +of about an hour each. And now I know a lot more about how the DDC works! + +The DDC was created in the 1870s by Melvil Dewey, who [was a problematic +person][dewey], and as a result the DDC has [its share of issues][crit]. For +these reasons and others, many libraries are moving away from the DDC to other +systems such as the [Library of Congress classification system][loc] or the +[BISAC subject codes][bisac] used by many booksellers. Though it might be in +decline, it's widely-enough used that I still wanted to learn more about it. + +The DDC organizes works into one of the ten main classes shown above. Each class +has ten divisions (the second digit), and each division has ten sections (the +third digit). There are further subdivisions that can be applied for more +specific works. Overall, this forms a tree structure in which each subsequent +digit traverses down the tree to a more specific topic. Works are classified +into the node which is as specific as possible, so in general a shorter number +or a number with fewer non-zero terminal digits will refer to a work that covers +a broader range of topics. + +In order to properly class works, there are two primary variables to consider: +the subject/topic and the discipline. For example, you might class a work on +dogs either in 599.77 (Natural sciences and mathematics > Animals > Mammals > +Carnivores > Dog Family), or in 636.7 (Technology > Argiculture and related +technologies > Animal husbandry > Dogs), depending on whether it was a book +about the physiology of dogs or on keeping dogs as pets. + +Of course, sometimes a work covers multiple topics or even multiple disciplines. +The DDC has rules which dictate how these situations should be handled. (To +continue the dog example, if you look in 599.77, there is a note which says +"class interdisciplinary works on dogs in 636.7," so if a work covered both the +biology and raising of dogs, it should be classed in 636.7). + +If you were to buy a hard copy of the DDC, you'd notice that there are a few +different parts. The main part that people think of as the DDC is called the +"schedules." This is the big list of all the top-level numbers, arranged into +chapters for each main class. There's also an introduction, which has rules for +deciding where works should be classed. For example the rule of fuller treatment +says that if a work covers two or more topics, but covers one topic more fully +than all the others, the work should be classed under that topic. There's also +the rule of two, which states that if a work covers two topics fairly equally, +it should be classed under the lower number. For example, a work on with equal +treatment of French bulldogs (636.72) and Welsh corgis (636.737) should be +classed under the lower number, 636.72. + +In addition to the introduction and the schedules, there's also the manual which +helps you resolve some specific situations (usually you'll see a note in the +schedules like "See manual 636.72-636.75" that points you to go there), the +relative index, and the tables. The relative index is generally the starting +point for classifying a work. You can look up a topic alphabetically, and you'll +be pointed to all the different possible classifications. And finally, the +tables, which help classify works more specifically. + +This introduces a topic called "number building." The DDC doesn't actually +contain a specific entry for each possible topic, but relies on adding standard +subdivisions to numbers listed in the schedules. Table 1 contains the standard +subdivisions, which you can add as a suffix to pretty much any number you find +in the schedules. The standard subdivisions include: + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
—01Philosophy and theory
—02Miscellany
—03Dictionaries, encyclopedias, concordances
—04Special topics
—05Serial publications
—06Organizations and management
—07Education, research, and related topics
—08Groups of people
—09History, geographic treatment, biography
+ +For example, an encyclopedia of programming languages could be classed under +005 +(Computer programming, programs, data), .1 (programming), +3 (programming languages), —03 +(Dictionaries, encyclopedias, concordances) to yield the number 005.1303. The +book Cracking the Coding Interview, which is about the job of +programming , could be classed under 005.1023, again using 005.1 (programming) +and adding —023, the standard subdivision for "the subject as a +profession, occupation, hobby." + +There are four tables in total; table 2 is used in conjunction with the 09 +standard subdivision from table 1, e.g. a book about the architecture of Boston +might be classed under 720.9744, with 720 being the architecture, 09 being the +standard subdivision for geographic treatment, and 744 being the suffix from +table 2 for Massachusetts. You might expect the number to be 720.09744, and it +would be, except that in the schedules under 720, we are instructed to put the +standard subdivisions in .1 through .9. + +Table 3 contains subdivisions for literatures and literary forms and is only +used with the main class 800 Literature. For example, a collection of American +plays might be classed as 81 (American literature in English) + 3 (the +subdivision from table 3 for Drama) to get 813 as the result. + +Finally, table 4 contains subdivisions for languages, and is only used with the +400 Language main class. It's used to break down specific attributes of +language, such as —3 for dictionaries. So Webster's dictionary would be +classed as 420 (English and Old English) + 3 +(dictionaries) = 423. + +There's a lot to the system, and while there is still a lot I don't know, I now +know a lot more about how it works than I did previously! If I got something +wrong here, please email me about it! I'd love to learn more. + +[class]: http://nlc.nebraska.gov/handouts/classmaterials/ddcsummer2014/dewey.html +[dewey]: https://en.wikipedia.org/wiki/Melvil_Dewey#Controversies +[crit]: https://en.wikipedia.org/wiki/Dewey_Decimal_Classification#Influence_and_criticism +[bisac]: https://bisg.org/page/BISACSubjectCodes +[loc]: https://en.wikipedia.org/wiki/Library_of_Congress_Classification -- cgit v1.2.3