How does MRI determine its Readers Per Copy numbers and what accounts for variations in those numbers?
Readers Per Copy (RPC) is determined by dividing circulation numbers from the Audit Bureau of Circulation (ABC) into MRI’s audience estimates. MRI measures the total audience of a given title in the Survey of the American Consumer, and then, using the two most recent ABC statements, an average circulation figure is determined. For example, the circulation figure used for the Spring 2007 release is an average of ABC’s circulation numbers for June 2006 and December 2006. That circulation figure is divided into MRI’s total audience number to produce the RPC metric. MRI’s goal is to link, as closely as possible, the data collection periods for both audience figures and number of copies sold. There are two potential drivers for changes in RPC from one release to the next: changes in total magazine audience or changes in magazine circulation. Changes in magazine audience occur when different numbers of people claim to read a magazine. Changes in magazine circulation occur when different numb
