Our readings this week focused on classification and categorization, ways to organize (and describe) items based on their subject. As we’ve discussed in previous weeks, one of the primary purposes for classification is to collocate items on a shelf. That is, to ensure that similar items are shelved together. As we’ve also discussed, the utility of physical or shelf classification is questioned by some in this age of search engines and OPACs, while others point out the continued utility of physical or electronic browsing, which is enabled by classification. Examples of classification schemes are Dewey Decimal Classification (DDC) or Library of Congress Classification (LCC).
A few of the readings also mentioned subject categorization by the assignment of subject headings. Subject headings are designed to indicate an item’s “aboutness,” what a document is about, its topic or subject. One of the most popular subject heading lists is the Library of Congress Subject Headings (LCSH)—not to be confused with the LCC mentioned above. (Yet another example of confusing library-world acronyms!)
Although they both describe what an item is about, subject headings differ from classification schemes in a few ways:
- Subject headings are presented in words or phrases similar to natural language. Classification schemes use some form of notation to indicate a subject. (See example below.)
- Each item is assigned only one classification code (it can have only one physical shelf location). However, an item is often assigned multiple subject headings. (See example below.)
Example subject headings (LCSH) and classification code (LCC) for a book:
- Information organization.
- Information organization > Technological innovations.
- Library science > Information technology.
- Z666.5 .N49 2013g
Finally, here are a few questions to prompt your thinking as you post to the blog. Feel free to answer any of these, or instead to post your own comment or question(s).
- What do you think of enumerative classification systems, as opposed to faceted or analytico-synthetic? What are some pros and cons of these systems?
- What do you think of Hjorland’s assessment of classification’s continued purpose in the age of search engines like Google?
- Rowley offered an in-depth look at subject heading systems. Like Hjorland, she concluded that these systems are still relevant for machine searching. Do you agree or disagree?
- Libraries still hold large collections of physical books, though many are housing increasing parts of these collections in off-site storage facilities. Is shelf classification still useful for a library’s physical collection, or are new methods of shelving by book size (retrieving by barcode, often assisted by robotics) sufficient?