PUBLICATION - The November 2002 issue of the Chicago Fed Letter is titled 'A regional perspective on the U.S. business cycle'. It is not difficult to come up with a definition of the business cycle that most of us would understand. A thornier issue is how to come up with an empirical measure of the business cycle. This article tackles the question and, in the process, offers a new measure of the U.S. business cycle, derived from regional data. A highlight of this approach is that it facilitates