Policy for the Use of the ChicagoID

The University of Chicago has many needs to identify individuals for use in computer systems, access to buildings, reporting, and for other recognition purposes. To that end, the University has created an identifier which it associates with persons to help it manage this diverse set of needs.

The identifier, called the ChicagoID, is assigned to an individual upon initial association with the University. It is unique, and each person is assigned only one ChicagoID. The ChicagoID is maintained permanently, and never reassigned to anyone else.


The ChicagoID is a 9 character string which is unique to each individual that it is assigned to. It is 8 digits followed by an alphabetic character, of which the first digit is a check digit for the remaining 8 characters. Each is randomly assigned to a person from the set of unassigned ChicagoIDs. No elective replacement of an assigned ChicagoID is permitted.



The ChicagoID is used to identify faculty and other academic appointees, staff, students, alumni, affiliates, postdoctoral researchers, and any other associated individuals who need access to or make use of services, systems, properties, or facilities owned or operated by the University, or for whom records are maintained in the University’s core business systems. It must not be used as a password or proof that its bearer is the person to whom it was assigned. Other measures must be taken when authentication of a person or of a ChicagoID is needed.

As a unique identifier for a person, the ChicagoID by itself is not sensitive data. However, when the ChicagoID is linked to sensitive data, the resulting assemblage must be protected to the same extent as the sensitive data. Further, associating ChicagoIDs with other data provides a personally identifiable context for that data, and the result may be sensitive even if the linked data, in isolation, is not. For example, a list of salaries that does not show who the salaries belong to may be acceptable to be published in a public forum, but linking ChicagoIDs to salaries changes the sensitivity of the result.

The ChicagoID is the property of The University of Chicago, and should not be transferred or used outside of the University’s purposes.


Changes to the Identifier

In some cases, independent University business processes give rise to a circumstance in which a person is assigned more than one ChicagoID. When this is discovered and remedied, their ChicagoID will appear to change in some contexts. Hence, use of the ChicagoID may carry with it the need to be able to handle these changes. A history of such changes is available for this purpose.

Category: Account and Identity
Policy Owner: tbarton