Slote Weeding System
with thanks to Jennie Kelson, Buckinghamshire Healthcare NHS Trust Library Service
Weeding Library Collections by Stanley J. Slote4th ed. Libraries Unlimited, 1997.
The book is available for loan from the British Library.
Age is often used as a primary criterion for weeding medical library collections. However, we were worried that some relevant stock would be removed if an arbitrary publication date (eg 10 years) was used as the sole means of selecting stock to be weeded. The Slote method, previously used in public and academic libraries, provided a possible objective method to quickly and easily identify older stock that was still relevant to library users.
The first step in the method is to determine the “shelf-time period” (ie how long a book remains on the shelf between loans), which is then used to calculate the cut-off circulation date.
In late 2005 over a period of about 4 months, we recorded the second most recent year due date for all books borrowed during this period. For instance, if a book had the following dates recorded on the date slip – 2 May 1999, 16 Feb 2002, 31 Aug 2003, 13 Jun 2006, 19 Jan 2008, then you would record a year date of 2006 (this was done on a form using five bar gates for counting). We had to keep collecting these dates for consecutive borrowed books until we had recorded over 400 borrowings (in order to obtain a reasonable sample size). This was done manually since we had a manual loan system in place at the time. It should be must quicker and easier to collate this data using the history details on SWIMS.
Year of previous due date / Total books / % / Cum. %2005 / 146 / 33.8 / 33.8
2004 / 149 / 34.5 / 68.3
2003 / 54 / 12.5 / 80.8
2002 / 40 / 9.3 / 90.1
2001 / 18 / 4.2 / 94.3
2000 / 13 / 3.0 / 97.3
1999 / 9 / 2.1 / 99.4
1998 / 1 / 0.2 / 99.6
1997 / -
1996 / 2 / 0.4 / 100.0
Pre 1996 / -
432
No date (ie never borrowed) / 36
We then went through the collection, inserting a weed flag (these we copied onto bright green paper) into each book that had not been borrowed in 2001 or later. The weed notice was displayed in the library, at the end of book shelves, notices were put in the staff bulletin and email messages were sent out to all staff. The notices gave staff a period of 4 months in which to comment. Some staff requested lists of books selected for weeding. These were generated from our catalogue database and sent to staff. Any books marked with a weed flag that were borrowed during the consultation period were then marked to be kept. (Ideally, all weeding candidate books should be taken off the shelves and stored somewhere else but we did not have the space to do this).
At the end of July, we then removed tagged books and withdrew them from our catalogue. Occasionally we elected to keep some items (mainly relating to the history of the hospital or some govt reports) that had been marked for weeding. We were able to throw away over 2,500 items and no-one seems to have missed them.
I found the Slote method to be an easy and objective method to rapidly identify items for weeding. We did however find a number of instances where out of date stock had been borrowed recently and therefore would have remained in the collection if we had not made further checks. Newer editions of these books were then prioritised for purchase.
There are a couple of other references about the Slote method showing how it was used in a UK academic library and a US public library. They are:
- Weeding without tears by L Roy in Collection management 1990, vol 12(1-2) p 83-93
- Weeding an academic lending library using the Slote method by R Williams in Brit J Academic Librarianship 1986, vol 1(2) p 147-159.
The method sounds quite complicated however Slote’s book is very easy to use and includes lots of worked examples.