Periodic weeding of the library collection is necessary to maintain the overall quality of the collection by removing obsolete, inappropriate or damaged materials. Weeding has been shown to improve patron perception of library quality and lead to increased circulation.
Like selection, de-selection is a complex task that requires weighing multiple competing variables to arrive at a decision. The following criteria are meant to be guidelines and cannot be applied in a formulaic manner. Decisions made regarding de-selection are based primarily on the professional judgment of the librarian.
- Publication Date. Generally, books over 25 years old should be considered for de-selection. Certain subjects (such as computer science) may be as little as five years old while other subjects should not be weeded based on age.
- Volume does not meet current collection guidelines
- The book is poorly written
- Contains incorrect information
- Outdated information or outmoded technology
- Books that do not support any program at the University are strong candidates for de-selection.
- Physical Condition and appearance. Physical condition may be a consideration for de-selection if the volume is not being used significantly. If the volume has high usage statistics it should be repaired or replaced.
- Use. In general, books used within the last 5 years should not be considered for de-selection. Books that have not circulated for more than 10 years should be considered strong candidates for de-selection.
- Duplicate volumes. Check usage statistics to determine if maintaining duplicate volumes in the collection is warranted.
- Ephemeral or popular materials. De-select if older than 10 years.
- Newer edition available.
- Foreign language not supported. Books in a foreign language or dealing with instruction in a foreign language for which the University does not offer instruction should be considered for de-selection.
- Consultation with subject specialist. In case of uncertainty the opinion of a subject specialist may be useful to determine the suitability of a title.
- Changes to academic programs. If a program was discontinued there may be materials that are no longer needed. Likewise, addition of a program or significant changes to a program could cause changes in the use patterns of materials. This should be taken into account when evaluating usage statistics.
- Subject specific criteria. There are many subjects or collections for which special consideration must be taken. In these instances it is the responsibility of the librarian in charge of that subject area to note these additional factors before beginning a de-selection project.