The German Audit Bureau of Circulation (IVW) has neutrally and objectively recorded and audited the distribution of advertising media since 1949. With the establishment of the IVW, media providers (publishers), advertisers and advertising agencies created an effective controlling system which is under their joint supervision. Almost all relevant advertising media categories are covered under the umbrella of the IVW: newspapers, magazines and other periodically appearing press products, broadcast media (radio and TV), cinema advertising and digital media.The underlying idea is simple and obvious. In order to function, the advertising market requires performance data regarding the advertising media that are offered on the market. However, if these data were collected by each provider of an advertising medium for its own advertising media with its own individual methods, on the one hand, no comparability with the data of other providers would be guaranteed, and on the other hand, there would also be no independent assurance of data quality. The advertising market players transferred these tasks to a common parent institution: the IVW. The results of the IVW's work provide reliable data for the market, for professional advertisers and performance-based competition between the media. As an independent, non-commercial, and neutral auditing organization, the IVW provides the media and advertising industry, and interested public, with basic data for the marketing of media as advertising.