UW–‍Madison Libraries Loan History Anonymization

Last updated on January 6, 2026

The UW–‍Madison Libraries, in coordination with all Universities of Wisconsin campuses, made a privacy-positive change to our data retention for circulation transactions in 2025: we began to “anonymize” lending history data after six months [1]. Anonymization means that we retain a record of the transaction, but it will no longer identify the individual who borrowed the item.

In the past, the Libraries retained the circulation and lending history for all people in our database, along with their identifying information. This data is stored so we can analyze the use of our materials and understand collection trends. We also use this information in annual reports, such as the Libraries’ submissions to national educational statistics, though the UW–‍Madison Libraries do not share circulation history with personally identifiable information with third parties. While the Libraries need usage information, we don’t need personally identifiable information attached to it. We made the change to anonymization to take a more proactive, privacy-first stance towards usage data, and incorporate the data privacy principles of data minimization and storage limitation. “Freedom to read” is one of tenets of librarianship and more information can be found at the American Library Association’s website: Privacy: An Interpretation of the Library Bill of Rights. The right to privacy includes the right to open inquiry without having the subject of one’s interest examined or scrutinized by others.

Feedback about the Libraries anonymization project has been positive! Dorothea Salo, Distinguished Teaching Faculty IV in the Information School is a supporter of privacy initiatives around campus: “I am so encouraged to see the Libraries successfully walk the tightrope between patron privacy and good patron service. Everything about the new circulation records retention program has been carefully thought through and sensibly built. Too many libraries have forgotten how important it is to ensure patrons cannot be harmed merely because of what they read or look up. I am proud to show my library-school students that the Libraries here take that responsibility seriously.”

While the Libraries now have a default retention model policy based on anonymization, we are aware that some people are interested in having the Libraries store this data for their own use. To support this user preference, we have also launched an opt-in loan history database which will retain individuals’ history dating back to May 2015, allowing them to view and download their own circulation records.

More information about your loan history is available on the Libraries’ Website.

[1] Archival materials and those identified as “special collections” are considered rare and typically extremely valuable holdings. As a result, loan data for these materials have a ten year retention schedule.