High Quality Content by WIKIPEDIA articles! In the United States radio listenership is gauged by Arbitron and others for both commercial radio and public radio. Arbitron and similar services provide estimates by regional market and by standard daypart, but does not compile nationwide information by host. Because there are significant gaps in Arbitron`s coverage in rural areas, and because there are only a few markets where Arbitron`s proprietary data can be compared against competing ratings measurers, there is a great deal of estimation and interpolation when attempting to compile a list of the most-listened-to radio programs in the United States.