Yale College has an inventory of thousands of courses. Departments sometimes find they are running short on available course numbers to assign to new courses.
As a practice, it is a good idea to clean up your inventory every few years; it is a good summer project. Deactivate courses that haven't been taught in seven years and courses taught by faculty who have retired or left Yale.
Email firstname.lastname@example.org to ask for a report that lists courses that have not been taught in 7 years.