(while I'm on a much-needed vacation, I'm re-posting some things from my old blog)
This appeared January 5, 2007.
Weeding, variously called "pruning", de-selection, de-accessioning, collection management, is a vital part of maintaining a healthy, vibrant, welcoming library collection. It is the careful, thoughtful removal of items from the collection. Reasons for weeding include:
- No longer within the scope of the collection
- Duplicate copies
- Low circulation (therefore low interest)
- Poor condition (replacement copies may be added)
- No circulation within x time period
- Information is out of date or superseded
How the time period is determined, or if the book can be repaired, or any of these other things are determined by the library mission and policies and by the professional judgment of the librarian responsible for managing the collection.
Research collections are rarely, if ever, weeded. Books are repaired and/or moved to off site storage. If they are weeded, the circ period may be within 10 years.
Public libraries, on the other hand, especially branch collections, usually will weed more aggressively. First, the books are handled much more roughly and so can be in much poorer shape. Second, the mission of the library is for the local citizen's person information needs like health information (should be rigorously and continuously weeded), legal information (should be rigorously and continuously weeded), self-help, hobby related, entertainment, and educational materials for both children and adult learners. Libraries that fail to weed will have out of date and possibly harmful materials. Sections like travel books where there are new copies every year should also be weeded -- who wants a restaurant guide from 1999?
Weeding is continuous in many libraries and it's part of the job description for the librarians. In other libraries, it's only done when necessary to free up space.
All libraries should have a policy that is agreed upon by the highest levels of library management. The policies should be different for different communities with different needs and should be different for different subject areas. Public libraries may have this policy approved by the library board.
One of the books I always keep near to hand and reference quite regularly here is F.W. Lancaster's If You Want to Evaluate Your Library... 2nd ed. (Champaign, IL: University of Illinois, 1993). Chapter 6 is on "Obsolescence, Weeding, and the Use of Space." I like his method because in journal selection, too, he comes up with a set of measures and then has you weigh each and score the total for each item. For weeding he has last recorded circ date, date of publication, on "recommended" list, physical condition. He has these weighted so circ date is most important. Finally a quote from him (p.116)
Weeding can improve the quality of a collection. When old and unused books are removed, the shelves appear more attractive to users and it is easier for them to find the newer or more popular items they are likely to be looking for. An effective weeding program has been known to increase circulation (Slote, 1989), although no evidence of this was detected by Roy (1990).