[1] Nielsen and similar services provide estimates by regional market and by standard daypart, but do not compile nationwide information by host.
Because there are significant gaps in Nielsen's coverage in rural areas, and because there are only a few markets where the company's proprietary data can be compared against competing ratings tabulators, 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.
In 2009, Arbitron, the American radio industry's largest audience-measurement company at the time (since subsumed into its television counterpart Nielsen), said that "the job of determining number of listeners for (any particular program or host) is too complicated, expensive and difficult for them to bother with.
In addition to Talkers' independent analyses, radio companies of all formats include estimates of the audience in news releases.
Thus, it is impossible under current survey techniques to determine the listenership of an individual event such as the Super Bowl; even in cases (such as in PPM markets) where such measurement is feasible, the radio industry's business model relies on selling advertising parceled by daypart rather than individual show or event.
In 2022 and 2023, Nielsen released a "far from complete" report suggesting that National Football League games are among the most-listened-to events on radio.
[20] For most of its existence, Talkers Magazine compiled Arbitron's data, along with other sources, to estimate the minimum weekly audiences of various commercial long-form talk radio shows; its list was updated monthly until the magazine unceremoniously dropped the feature in 2016, then resumed publication in 2017.
[21] The 2017 reintroduction also incorporates off-air distribution methods (particularly those that are Internet-based) but not satellite radio, as Talkers could not access data for that medium; as a result, the estimates for most shows increased dramatically when compared to the 2015 methodology.
[37][38] Eastlan Ratings, a service that competes with Arbitron in several markets, includes satellite radio channels in its local ratings; Howard 100 has registered above several lower-end local stations in the markets Eastlan serves, the only satellite station to do so.
[42] President Franklin D. Roosevelt's irregularly scheduled fireside chats, simulcast on all of the major networks, consistently reached over 50 percent of the listening audience during his last five years in office.
[44] During the early 1990s, Chuck Harder was Limbaugh's most prominent rival among talk shows discussing sociopolitical issues.
Paul Harvey, at his peak, drew an estimated 25 million listeners to his 15-minute daily program.
The public radio series Car Talk with Click and Clack had approximately 4 million listeners immediately prior to ending its original run, ranking it among the most-listened-to weekend radio programs in the United States; individual affiliates noted that the hour of highest listenership on their stations were during Car Talk, hence why it was kept in reruns for five years afterward.