I had a chance recently to listen to a colleague in the public library sector talk about classification numbers and the assigning of Dewey call numbers to materials that were to be housed in a specialized collection which would be devoted entirely to business clientele.
One of the challenges she faced was the fact that so many of the resources were catalogued in the 650s, with most of those being in the 658s. She found books on how to write business plans for bakeries and wondered if she could put those books somewhere in the 640s along with other books about commercial baking. She also had a book on business writing for performing artists and wanted to put that somewhere in the 700s, etc. She reported that her request to reclassify materials for this collection created considerable controversy in the technical services department with cataloguers who agreed with the appropriateness of reclassification to make the organization of materials more relevant in the specialized collection to other cataloguers who felt that there is only really one classification number which best describes the resource. I noted that she didn't mention any complaints about the increased work reclassification would create.
It was interesting to listen to the discussion as well as the comments made by other librarians. It reinforced in my mind the common misunderstanding of the key purposes of classification numbers. First of all, books need to have a place on the shelf and, second of all, it helps those who like to browse to have books on similar topics shelved together. Because a book is seldom about a single topic or it can be difficult to find a single subject heading which can accurate describe some complex topics, the cataloguer selects a classification number that he or she thinks will most closely match the way patrons are likely to browse for that item. Those who don’t classify resources may not be aware of the amount of subjectivity involved in selecting a classification number for certain types of resources. This is particularly true when a work is multidisciplinary or contains highly detailed information about a variety of different subjects. In reality, if anyone wants to browse by subject, the best way to do that is a subject search in the OPAC.
So, you may wonder, what happened with the book classification in the business library? I generally don’t like to think of things in terms of winner and losers but if I were to say who the winner was, I’d have to say that it was the librarian who was giving the talk. In the end, the classification was redone so that if a business book addressed a special type of business, that book was reclassified somewhere within the classification range for the subject of that business. If the books were just generally on business or business skills, they were classified somewhere in the 650s. She said that less than 10% of the collection was reclassified but it did mean shifting the collection around a bit so work needed to be done.
The librarian didn’t set out to do a scientific study as to whether or not changing the classification numbers increased use of the materials. While there was an overall increase in use of materials, she said that she didn’t have a way to know that the increase wasn’t due to the fact that people were starting to learn about the library through word of mouth and the increasing number of patrons through the door meant an increase in borrowing of resources. However, she did say that she found it much easier to just walk to the shelf with patrons and go directly to the sections where they might like to browse. She said that if she wanted to show people general books about applying for grant money, those books were all in one place but if the grant money was specific to a preserving a heritage building, for example, she could take them to a different section and while the patrons were browsing around in that section they would invariably find other books of interest and without happening to see them on the shelf in the same general area, likely would not have found.
In listening to all of this it became apparent to me that subject headings are the most useful for searching for materials in discovery systems and classification numbers for searching around directly on the shelves. If you want to do a good search, it’s best to do both. While some fairly precise searching can be done, the door can also be opened to the chance of serendipitous discovery.