Please refer to the Libraries’ Preservation Policy for specific information on preservation of both physical and digital collections.

The Libraries acquires single copies of resources, except in rare cases when sufficient demand for multiple copies is known, can be reasonably projected, or where the item possesses particular artifactual value. The decision to collect multiple copies is carefully balanced against a variety of factors, including specific requests from faculty and researchers demonstrating need for multiple copies, the total cost of acquisition, storage options or constraints, number of holdings across libraries generally, and the broad ecosystem of partnerships through which users may borrow or otherwise access the same or similar collections (e.g., opportunities for inter-library loan that will reasonably and affordably meet needs of users in a timely manner; availability of electronic versions of print materials, whether through open access or library-supported subscriptions).

Accessioning an item or collection requires a formal decision to acquire it, either through a purchase or gift agreement, and these collections are recorded in the appropriate bibliographic or archival management tool. Decisions to remove items from the University's collection are made within the context of the Libraries' core mission to steward the preservation of human knowledge over time, and with careful consideration of the potential impact on research and teaching. Decisions are purposeful and made with the broadest and most inclusive input possible. Given the increasingly interdisciplinary nature of scholarship, candidates for deaccession are made known to all of the Libraries’ subject specialists and curators well in advance for their assessment and feedback. Librarians and curators are encouraged to contact faculty to provide input on these decisions.

Decisions to deaccession items from the general collections, like decisions to acquire new titles for the collection, are made within the context of the collection policy, so that the integrity of the total collection is not impaired, but in fact may be enhanced when unneeded materials are removed from the collections. 

All decisions are made with care, and placed in the context of practices in the field. Factors that influence decisions to remove items from the general collection are also factors that may, inversely, influence a decision to instead retain or replace them, and may include: 

• continued relevance to the academic profile of the University and the collecting profile of the Libraries;

• the physical copy is disintegrating or otherwise no longer serviceable in its print/tangible form (in these instances, either a preservation photocopy is made, a digital surrogate created or obtained, and/or the item is evaluated for replacement);

• the item is on an obsolete format (in these instances, the Libraries will generally take steps to digitize materials on obsolete formats in advance of deaccessioning, except when already readily available via other means; the Libraries will generally retain items on obsolete formats, even after digitization, if the item is unique or not widely held by other libraries, and/or the original format itself has artifactual or scholarly value);superseded editions/volumes evaluated as having limited scholarly value; 

• electronic duplication with perpetual ownership and/or access (e.g., direct purchases, Project MUSE, JSTOR, HathiTrust);

• multiple copies of low-use titles across multiple Columbia library locations;

• widely held by partner institutions whose collections are readily accessible to Columbia’s users (e.g., Columbia’s partners within ReCAP, Borrow Direct, and MaRLI);

• widely held by libraries across Columbia’s broader national network of resource sharing/inter-library loan partners.

U.S. federal government documents are deaccessioned in accordance with protocols established by the Federal Library Depository Program. 

Materials that are declared lost or missing, or in poor/unusable condition will be replaced at the discretion of the appropriate librarian, in accordance with the collection development policies in effect at that time. Factors described above that may influence decisions to deaccession materials from the general collection may well apply to a decision to instead replace materials due to their physical condition or lost/missing status. 

The commitment of the University to provide shelving space for physical materials is both a significant capital investment and a significant annual operating cost. As collections grow, space must be made available to house them. In 2000, Columbia University entered into a partnership with Princeton University and New York Public Library to build a high-density, preservation-quality storage facility called The Research Collections and Preservation Consortium (ReCAP) that would both preserve and share collections across partner institutions. In 2019, Harvard University Library joined the ReCAP partnership as a full member.

Location decisions are not made in an automated fashion. Librarians and curators apply a variety of criteria to strategically manage which materials are housed on campus and which are housed offsite at ReCAP. Location decisions are a careful and continually evolving balance between space management and fulfilling the needs of research and teaching, with the needs of the latter taking precedence whenever possible. 

It is not an expectation that all criteria for determining location are the same across all subject areas. The rationale for locating items at ReCAP for one subject area may well be the same reason for locating items on campus in another subject area. Please consult individual subject-specific collection development policies to see the strategies and criteria applied within any given subject area in determining locations.

Common criteria for locating an item on campus include, but are not limited to:

• high use;

• newly-acquired / newly published;

• used in current research or teaching;

• specific languages in each subject area;

• major presses;

• faculty authors;

• canonical/core titles;

• critical editions;

• major authors;

• current (or high use) reference materials.

Common criteria for locating an item at ReCAP include, but are not limited to:

• the condition or nature of the item requires it be housed in a secure, long-term preservation environment;

• low use (as defined in each subject area);

• specific languages in a given subject area;

• highly specialized subjects;

• not actively used in current research or teaching;

• older imprints where variation in edition is not of scholarly interest;

• print books and print journal runs that are available online;

• minor presses;

• minor authors.

Librarians and Curators will consult with faculty in the event of a major relocation to ReCAP. Faculty and researchers are invited to confer with liaison librarians and curators for more information on how location decisions are made within particular collections, disciplines, and subject areas, as well as to submit requests that an item’s location be changed.