Answered By: Kathleen Zamietra
Last Updated: Sep 27, 2023     Views: 60

In addition to acquiring new materials, collection development involves identifying and withdrawing selected resources that are no longer useful.  Deaccessioning, or weeding, is an essential and continuous component of collection management.  Permanently removing materials for reasons such as being out of date, unused, or damaged from Trexler Library ensures our collection’s health and viability.  Weeding maximizes the usefulness of the collection and ensures that it continues to support the instructional and research needs of DeSales University’s faculty, staff, and students.  Trexler Library’s Collection Development Policy guides all weeding decisions, in keeping with our mission to collect, organize, and provide access to information. 


Responsibility for Weeding 

Final responsibility for the identification of and weeding materials from the Trexler Library collection rests with the Instruction Services Librarians and Access Services Team.  Individuals who participate in weeding include the library director, librarians, and other library personnel.  Trexler Library encourages the teaching faculty to work with and provide feedback to the Instruction Services Librarians to identify materials to deaccession. 


Criteria for Weeding 

  • Currency – The content of library materials should be accurate and up to date.  Materials that are superseded by newer, revised, or updated editions may be weeded.  The library considers faculty and students whose scholarship and teaching require historical texts in areas such as psychology, mathematics, and physics. 

  • Usage – Low or no usage may be a factor in weeding decisions.  Librarians may consult circulation statistics or other reports to determine viable candidates for weeding. 

  • Physical Condition – Materials that are badly deteriorated or damaged and are beyond reasonable repair will be weeded. 

  • Duplicates – Due to space constraints the library may weed duplicate copies of materials.  Librarians will consider the need for more than one copy of a title on hand, especially for titles that are heavily used or part of a university-wide program. 

  • Completeness – Materials that are part of multi-volume sets of which the library does not have all volumes may be weeded. 

  • Uniqueness – The library will not weed materials that are considered unique. 

  • Format Obsolescence – Materials in obsolete formats may be weeded if the content is available elsewhere or if the material is in poor condition. 

  • Availability - Materials available from alternative sources or locations will be weeded. 


Trexler Library has identified the CREW method for our deaccession procedure.  CREW guidelines consist of three parts: year of latest copyright/years since last checkout/MUSTIE factors.  MUSTIE is an acronym which is applied to material and indicates when an item should be evaluated for deaccessioning.  MUSTIE stands for: 

Misleading and/or factually inaccurate 

Ugly (worn beyond mending or rebinding) 

Superseded by a new edition/better source 

Trivial (of no discernable literary or scientific merit) 

Irrelevant to the needs/interests of the DeSales University community 

Elsewhere (the material may be borrowed from another source expeditiously)