The nominations are based on results from the iHeartRadio Chart. It includes listener feedback and performance data, according to airplay; digital streaming data from the iHeartRadio platform, including sales, social, online video data and tags from BigChampagne and Shazam. The iHeartRadio Countdown, the two-hour weekly program, highlights the top 20 contemporary hit radio songs in the iHeartRadio Chart. The latter is supplied and compiled by Mediabase. In addition, every public-voting category (nine in 2018), includes social hashtags as the primary voting mechanism.